Monday,

August 18, 2003

Part II

Environmental 

Protection Agency

40 CFR Parts 141, 142, and 143

National Primary Drinking Water 

Regulations: Stage 2 Disinfectants and 

Disinfection Byproducts Rule; National 

Primary and Secondary Drinking Water 

Regulations: Approval of Analytical 

Methods for Chemical Contaminants; 

Proposed Rule

49548 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 141, 142 and 143 

[FRL–7530–3] 

RIN 2040–AD38 

National Primary Drinking Water 

Regulations: Stage 2 Disinfectants and 

Disinfection Byproducts Rule; National 

Primary and Secondary Drinking Water 

Regulations: Approval of Analytical 

Methods for Chemical Contaminants

AGENCY: Environmental Protection 

Agency.

ACTION: Proposed rule.

SUMMARY: In this document, the 

Environmental Protection Agency (EPA) 

is proposing maximum contaminant 

level goals (MCLGs) for chloroform, 

monochloroacetic acid (MCAA) and 

trichloroacetic acid (TCAA); National 

Primary Drinking Water Regulations 

(NPDWRs) which consist of maximum 

contaminant levels (MCLs) and 

monitoring, reporting, and public 

notification requirements for total 

trihalomethanes (TTHM—a sum of 

chloroform, bromodichloromethane, 

dibromochloromethane, and 

bromoform) and haloacetic acids 

(HAA5—a sum of mono-, di-, and 

trichloroacetic acids and mono- and 

dibromoacetic acids); and revisions to 

the reduced monitoring requirements 

for bromate. This document also 

specifies the best available technologies 

(BATs) for the proposed MCLs. EPA is 

also proposing additional analytical 

methods for the determination of 

disinfectants and disinfection 

byproducts (DBPs) in drinking water 

and proposing to extend approval of 

DBP methods for the determination of 

additional chemical contaminants. This 

set of regulations proposed today is 

known as the Stage 2 Disinfectants and 

Disinfection Byproducts Rule (Stage 2 

DBPR). EPA’s objective for the Stage 2 

DBPR is to reduce the potential risks of 

reproductive and developmental health 

effects and cancer associated with 

disinfection byproducts (DBPs) by 

reducing peak and average levels of 

DBPs in drinking water supplies. 

The Stage 2 DBPR applies to public 

water systems (PWS) that are 

community water systems (CWSs) or 

nontransient noncommunity water 

systems (NTNCWs) that add a primary 

or residual disinfectant other than 

ultraviolet light or deliver water that has 

been treated with a primary or residual 

disinfectant other than ultraviolet light.

DATES: The Agency requests comments 

on today’s proposal. Comments must be 

received or post-marked by midnight 

November 17, 2003.

ADDRESSES: Comments may be 

submitted by mail to: Water Docket, 

Environmental Protection Agency, Mail 

Code 4101T, 1200 Pennsylvania Ave., 

NW., Washington, DC 20460, Attention 

Docket ID No. OW–2002–0043. 

Comments may also be submitted 

electronically or through hand delivery/

courier by following the detailed 

instructions as provided in section I.C. 

of the SUPPLEMENTARY INFORMATION

section.

FOR FURTHER INFORMATION CONTACT: For 

technical inquiries, contact Tom 

Grubbs, Office of Ground Water and 

Drinking Water (MC 4607M), U.S. 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460; telephone (202) 564–5262. 

For regulatory inquiries, contact Jennifer 

McLain at the same address; telephone 

(202) 564–5248. For general information 

contact the Safe Drinking Water Hotline, 

Telephone (800) 426–4791. The Safe 

Drinking Water Hotline is open Monday 

through Friday, excluding legal 

holidays, from 9 a.m. to 5:30 p.m. 

Eastern Time.

SUPPLEMENTARY INFORMATION: 

I. General Information 

A. Who Is Regulated by This Action? 

Entities potentially regulated by the 

Stage 2 DBPR are community and 

nontransient noncommunity water 

systems that add a primary or residual 

disinfectant other than ultraviolet light 

or deliver water that has been treated 

with a primary or residual disinfectant 

other than ultraviolet light. Regulated 

categories and entities are identified in 

the following chart.

Category Examples of regulated entities 

Industry ............................................................... Community and nontransient noncommunity water systems that add a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or 

residual disinfectant other than ultraviolet light. 

State, Local, Tribal, or Federal Governments .... Community and nontransient noncommunity water systems that add a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or 

residual disinfectant other than ultraviolet light. 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

regulated by this action. This table lists 

the types of entities of which EPA is 

now aware that could potentially be 

regulated by this action. Other types of 

entities not listed in this table could 

also be regulated. To determine whether 

your facility is regulated by this action, 

you should carefully examine the 

definition of ‘‘public water system’’ in 

§ 141.2 and the section entitled 

‘‘coverage’’ (§ 141.3) in Title 40 of the 

Code of Federal Regulations and 

applicability criteria in § 141.600 and 

141.620 of today’s proposal. If you have 

questions regarding the applicability of 

the Stage 2 DBPR to a particular entity, 

contact one of the persons listed in the 

preceding section entitled FOR FURTHER

INFORMATION CONTACT. 

B. How Can I Get Copies of This 

Document and Other Related 

Information? 

1. Docket. EPA has established an 

official public docket for this action 

under Docket ID No. OW–2002–0043. 

The official public docket consists of the 

documents specifically referenced in 

this action, any public comments 

received, and other information related 

to this action. Although a part of the 

official docket, the public docket does 

not include Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

The official public docket is the 

collection of materials that is available 

for public viewing at the Water Docket 

in the EPA Docket Center, (EPA/DC) 

EPA West, Room B102, 1301 

Constitution Ave., NW., Washington, 

DC. The EPA Docket Center Public 

Reading Room is open from 8:30 a.m. to 

4:30 p.m., Monday through Friday, 

excluding legal holidays. The telephone 

number for the Public Reading Room is 

(202) 566–1744, and the telephone 

number for the Water Docket is (202) 

566–2426. For access to docket material, 

please call (202) 566–2426 to schedule 

an appointment.

2. Electronic Access. You may access 

this Federal Register document 

electronically through the EPA Internet 

under the ‘‘Federal Register’’ listings at 

http://www.epa.gov/fedrgstr/.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49549

An electronic version of the public 

docket is available through EPA’s 

electronic public docket and comment 

system, EPA Dockets. You may use EPA 

Dockets at http://www.epa.gov/edocket/

to submit or view public comments, 

access the index listing of the contents 

of the official public docket, and to 

access those documents in the public 

docket that are available electronically. 

Once in the system, select ‘‘search,’’

then key in the appropriate docket 

identification number. 

Certain types of information will not 

be placed in the EPA Dockets. 

Information claimed as CBI and other 

information whose disclosure is 

restricted by statute, which is not 

included in the official public docket, 

will not be available for public viewing 

in EPA’s electronic public docket. EPA’s 

policy is that copyrighted material will 

not be placed in EPA’s electronic public 

docket but will be available only in 

printed, paper form in the official public 

docket. Although not all docket 

materials may be available 

electronically, you may still access any 

of the publicly available docket 

materials through the docket facility 

identified in section I.B.1. 

For public commenters, it is 

important to note that EPA’s policy is 

that public comments, whether 

submitted electronically or in paper, 

will be made available for public 

viewing in EPA’s electronic public 

docket as EPA receives them and 

without change, unless the comment 

contains copyrighted material, CBI, or 

other information whose disclosure is 

restricted by statute. When EPA 

identifies a comment containing 

copyrighted material, EPA will provide 

a reference to that material in the 

version of the comment that is placed in 

EPA’s electronic public docket. The 

entire printed comment, including the 

copyrighted material, will be available 

in the public docket. 

Public comments submitted on 

computer disks that are mailed or 

delivered to the docket will be 

transferred to EPA’s electronic public 

docket. Public comments that are 

mailed or delivered to the Docket will 

be scanned and placed in EPA’s 

electronic public docket. Where 

practical, physical objects will be 

photographed, and the photograph will 

be placed in EPA’s electronic public 

docket along with a brief description 

written by the docket staff. 

C. How and to Whom Do I Submit 

Comments? 

You may submit comments 

electronically, by mail, or through hand 

delivery/courier. To ensure proper 

receipt by EPA, identify the appropriate 

docket identification number in the 

subject line on the first page of your 

comment. Please ensure that your 

comments are submitted within the 

specified comment period. Comments 

received after the close of the comment 

period will be marked ‘‘late.’’ EPA is not 

required to consider these late 

comments. 

1. Electronically. If you submit an 

electronic comment as prescribed 

below, EPA recommends that you 

include your name, mailing address, 

and an e-mail address or other contact 

information in the body of your 

comment. Also include this contact 

information on the outside of any disk 

or CD ROM you submit, and in any 

cover letter accompanying the disk or 

CD ROM. This ensures that you can be 

identified as the submitter of the 

comment and allows EPA to contact you 

in case EPA cannot read your comment 

due to technical difficulties or needs 

further information on the substance of 

your comment. EPA’s policy is that EPA 

will not edit your comment, and any 

identifying or contact information 

provided in the body of a comment will 

be included as part of the comment that 

is placed in the official public docket, 

and made available in EPA’s electronic 

public docket. If EPA cannot read your 

comment due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. 

a. EPA Dockets. Your use of EPA’s 

electronic public docket to submit 

comments to EPA electronically is 

EPA’s preferred method for receiving 

comments. Go directly to EPA Dockets 

at http://www.epa.gov/edocket, and 

follow the online instructions for 

submitting comments. Once in the 

system, select ‘‘search,’’ and then key in 

Docket ID No. OW–2002–0043. The 

system is an ‘‘anonymous access’’

system, which means EPA will not 

know your identity, e-mail address, or 

other contact information unless you 

provide it in the body of your comment. 

b. E-mail. Comments may be sent by 

electronic mail (e-mail) to OWDocket@epa.gov, Attention Docket ID 

No. OW–2002–0043. In contrast to 

EPA’s electronic public docket, EPA’s email system is not an ‘‘anonymous 

access’’ system. If you send an e-mail 

comment directly to the Docket without 

going through EPA’s electronic public 

docket, EPA’s e-mail system 

automatically captures your e-mail 

address. E-mail addresses that are 

automatically captured by EPA’s e-mail 

system are included as part of the 

comment that is placed in the official 

public docket, and made available in 

EPA’s electronic public docket. 

c. Disk or CD ROM. You may submit 

comments on a disk or CD ROM that 

you mail to the mailing address 

identified in section I.C.2. These 

electronic submissions will be accepted 

in WordPerfect or ASCII file format. 

Avoid the use of special characters and 

any form of encryption.

2. By Mail. Send three copies of your 

comments and any enclosures to: Water 

Docket, Environmental Protection 

Agency, Mail Code 4101T, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460, Attention Docket ID No. OW–

2002–0043. 

3. By Hand Delivery or Courier.

Deliver your comments to: Water 

Docket, EPA Docket Center, 

Environmental Protection Agency, 

Room B102, 1301 Constitution Ave., 

NW., Washington, DC, Attention Docket 

ID No. OW–2002–0043. Such deliveries 

are only accepted during the Docket’s 

normal hours of operation as identified 

in section I.B.1. 

D. What Should I Consider as I Prepare 

My Comments for EPA? 

You may find the following 

suggestions helpful for preparing your 

comments: 

1. Explain your views as clearly as 

possible. 

2. Describe any assumptions that you 

used. 

3. Provide any technical information 

and/or data you used that support your 

views. 

4. If you estimate potential burden or 

costs, explain how you arrived at your 

estimate. 

5. Provide specific examples to 

illustrate your concerns. 

6. Offer alternatives. 

7. Make sure to submit your 

comments by the comment period 

identified. 

8. To ensure proper receipt by EPA, 

identify the appropriate docket 

identification number in the subject line 

on the first page of your response. It 

would also be helpful if you provided 

the name, date, and Federal Register

citation related to your comments. 

Abbreviations Used in This Document 

AIPC All Indian Pueblo Council 

ALT Alanine aminotransferase 

AST Aspartate aminotransferase 

ASTM American Society for Testing 

and Materials 

AWWA American Water Works 

Association 

AwwaRF American Water Works 

Association Research Foundation 

BAT Best available technology 

BCAA Bromochloroacetic acid

49550 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

BDCM Bromodichloromethane 

CWS Community water system 

DBAA Dibromoacetic acid 

DBCM Dibromochloromethane 

DBP Disinfection byproduct 

DBPR Disinfectants and Disinfection 

Byproducts Rule 

DCAA Dichloroacetic acid 

DOC Dissolved organic carbon 

EA Economic analysis 

EC Enhanced coagulation 

EDA Ethylenediamine 

ED10 Maximum likelihood estimate of 

a dose producing effects in 10 

percent of animals 

EPA United States Environmental 

Protection Agency 

FACA Federal Advisory Committee 

Act 

FBRR Filter Backwash Recycling Rule 

GAC Granular activated carbon 

GC/ECD Gas chromatography using 

electron capture detection 

GWUDI Ground water under the direct 

influence of surface water 

HAA5 Haloacetic acids (five) (sum of 

monochloroacetic acid, 

dichloroacetic acid, trichloroacetic 

acid, monobromoacetic acid, and 

dibromoacetic acid) 

IC Ion chromatography 

ICR Information Collection Request 

IC/ICP–MS Ion chromatograph—

coupled to an inductively coupled 

plasma mass spectrometer 

IDSE Initial distribution system 

evaluation 

ILSI International Life Sciences 

Institute 

IESWTR Interim Enhanced Surface 

Water Treatment Rule 

IPCS International Programme on 

Chemical Safety 

IRIS Integrated Risk Information 

System (EPA) 

kWh/yr Kilowatt hours per year 

LED10 Lower 95 percent confidence 

bound of the maximum likelihood 

estimate of the dose producing 

effects in 10 percent of animals 

LH Luteinizing hormone 

LOAEL Lowest observed adverse effect 

level 

LRAA Locational running annual 

average 

LT1ESWTR Long Term 1 Enhanced 

Surface Water Treatment Rule 

LT2ESWTR Long Term 2 Enhanced 

Surface Water Treatment Rule 

MBAA Monobromoacetic acid 

MCAA Monochloroacetic acid 

MCL Maximum contaminant level 

MCLG Maximum contaminant level 

goal 

M-DBP Microbial and disinfection 

byproducts 

mg/L Milligram per liter 

MRL Minimum reporting level 

MRDL Maximum residual disinfectant 

level 

MRDLG Maximum residual 

disinfectant level goal 

MTBE Methyl tertiary butyl ether 

mWh Megawatt-hours 

NATICH National Air Toxics 

Information Clearinghouse 

NDIR Nondispersive infrared detection 

NDMA N-nitrosodimethylamine 

NDWAC National Drinking Water 

Advisory Council 

NF Nanofiltration 

NOAEL No Observed Adverse Effect 

Level 

NODA Notice of data availability 

NPDWR National primary drinking 

water regulation 

NRWA National Rural Water 

Association 

NTNCWS Nontransient 

noncommunity water system 

NTP National Toxicology Program 

NTTAA National Technology Transfer 

and Advancement Act 

ODA o-dianisidine dihydrochloride 

OMB Office of Management and 

Budget 

OSTP Office of Science and 

Technology Policy 

PAR Population attributable risk 

PE Performance evaluation 

PWS Public water system 

QC Quality control 

RAA Running annual average 

RFA Regulatory Flexibility Act 

RfD Reference dose 

RSC Relative source contribution 

RSD Relative standard deviation 

SAB Science Advisory Board 

SAC Selective anion concentration 

SBAR Small Business Advisory 

Review 

SBREFA Small Business Regulatory 

Enforcement Fairness Act 

SDWA Safe Drinking Water Act, or the 

‘‘Act,’’ as amended in 1996

SER Small Entity Representative 

SGA Small for gestational age 

SUVA Specific ultraviolet absorbance 

SWAT Surface Water Analytical Tool 

SWTR Surface Water Treatment Rule 

TAME Tertiary amyl methyl ether 

TCAA Trichloroacetic acid 

TCR Total Coliform Rule 

THM Trihalomethane 

TOC Total organic carbon 

TTHM Total trihalomethanes (sum of 

four THMs: chloroform, 

bromodichloromethane, 

dibromochloromethane, and 

bromoform) 

TWG Technical work group 

UMRA Unfunded Mandates Reform 

Act 

USDOE EIA U.S. Department of 

Energy, Energy Information 

Administration 

UV 254 Ultraviolet absorption at 254 

nm 

WTP Willingness To Pay

Table of Contents 

I. Summary 

A. Why is EPA Proposing the Stage 2 

DBPR? 

B. What Does the Stage 2 DBPR Require? 

C. What are the Economic Impacts of the 

Stage 2 DBPR? 

II. Background 

A. What is the Statutory Authority for the 

Stage 2 DBPR? 

B. What is the Regulatory History of the 

Stage 2 DBPR? 

C. How were Stakeholders Involved in 

Developing the Stage 2 DBPR? 

1. Federal Advisory Committee process 

2. Other outreach processes 

III. Public Health Risk 

A. Reproductive and Developmental 

Epidemiology 

1. Reif et al. 2000

a. Fetal growth 

b. Fetal viability 

c. Fetal malformations and other 

developmental anomalies 

2. Bove et al. 2002 

a. Fetal growth 

b. Fetal viability 

c. Fetal malformations 

3. Nieuwenhuijsen et al. 2000 

4. Additional epidemiology studies 

B. Reproductive and Developmental 

Toxicology 

1. EPA analysis and research 

2. Tyl, 2000 

a. Developmental defects 

b. Whole litter resorption 

c. Fetal toxicity 

d. Male reproductive effects 

3. World Health Organization review of the 

reproductive and developmental 

toxicology literature (2000) 

4. New Studies 

C. Conclusions Drawn from the 

Reproductive and Developmental Health 

Effects Data 

D. Cancer Epidemiology 

1. Population Attributable Risk analysis 

2. New epidemiological cancer studies 

a. New bladder cancer studies 

b. New colon cancer studies 

c. New rectal cancer studies 

d. Other cancers 

3. Review of the cancer epidemiology 

literature (WHO 2000) 

E. Cancer and Other Toxicology 

1. EPA criteria documents 

2. Other byproducts with carcinogenic 

potential 

a. 3-chloro-4-(dichloromethyl)-5-hydroxy2(5H)-furanone) (MX)—multisite cancer 

b. N-nitrosodimethylamine (NDMA)—

multisite cancer 

3. Other toxicological effects 

4. WHO review of the cancer toxicology 

literature (2000) 

F. Conclusions Drawn from the Cancer 

Epidemiology and Toxicology 

G. Request for Comment 

IV. DBP Occurrence within Distribution 

Systems 

A. Data Sources 

1. Information Collection Rule Data 

2. Other Data Sources Used to Support the 

Proposal 

B. DBPs in Distribution Systems

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49551

1. DBPs above the MCL occur at some 

locations in a substantial number of 

plants 

2. Specific locations in distribution 

systems are not protected to MCL levels 

3. Stage 1 DBPR maximum residence time 

location may not reflect the highest DBP 

occurrence levels 

C. Request for Comment 

V. Discussion of Proposed Stage 2 DBPR 

Requirements 

A. MCLG for Chloroform 

1. What is EPA proposing today? 

2. How was this proposal developed? 

a. Background 

b. Basis of the new chloroform MCLG 

i. Mode of action 

ii. Metabolism 

c. How the MCLG is derived 

i. Reference dose 

ii. Relative source contribution 

iii. Water ingestion and body weight 

assumptions 

iv. MCLG calculation 

v. Other considerations 

d. Feasibility of other options 

3. Request for comment 

B. MCLGs for THMs and HAAs 

1. What is EPA proposing today?

2. How was this proposal developed? 

a. Trichloroacetic acid 

b. Monochloroacetic acid 

3. Request for comment 

C. Consecutive Systems 

1. What is EPA proposing today? 

a. Definitions 

b. Monitoring 

c. Compliance schedules 

d. Treatment 

e. Violations 

f. Public notice and consumer confidence 

reports 

g. Recordkeeping and reporting 

h. State special primacy conditions 

2. How was this proposal developed? 

3. Request for comment 

D. MCLs for TTHM and HAA5 

1. What is EPA proposing today? 

2. How was this proposal developed? 

a. Definition of an LRAA 

b. Consideration of regulatory alternatives 

c. Basis for the LRAA 

d. Basis for phasing LRAA compliance 

e. TTHM and HAA5 as Indicators 

3. Request for comment 

E. Requirements for Peak TTHM and HAA5 

Levels 

1. What is EPA proposing today? 

2. How was this proposal developed? 

3. Request for comment 

F. BAT for TTHM and HAA5 

1. What is EPA proposing today? 

2. How was this proposal developed? 

a. Basis for the BAT 

i. BAT analysis using the Information 

Collection Rule treatment studies 

ii. BAT analysis using the SWAT 

b. Basis for the Consecutive System BAT 

3. Request for comment 

G. MCL, BAT, and Monitoring for Bromate 

1. What is EPA proposing today? 

2. How was this proposal developed? 

a. Bromate MCL 

b. Bromate in hypochlorite solutions 

c. Criterion for reduced bromate 

monitoring 

3. Request for comment 

H. Initial Distribution System Evaluation 

(IDSE) 

1. What is EPA proposing today? 

a. Applicability 

b. Data collection 

i. Standard monitoring program 

ii. System specific study 

iii. 40/30 certification 

c. Implementation 

2. How was this proposal developed? 

a. Applicability 

b. Data collection 

c. Implementation 

3. Request for comment 

a. Applicability 

b. Data collection 

c. Implementation 

I. Monitoring Requirements and 

Compliance Determination for Stage 2A 

and Stage 2B TTHM and HAA5 MCLs 

1. What is EPA proposing today? 

a. Stage 2A 

b. IDSE 

c. Stage 2B 

i. Subpart H systems serving 10,000 or 

more people 

ii. Subpart H systems serving 500 to 9,999 

people 

iii. Subpart H systems serving fewer than 

500 people 

iv. Ground water systems serving 10,000 or 

more people 

v. Ground water systems serving fewer 

than 10,000 people 

vi. Consecutive systems 

2. How was this proposal developed? 

a. Sampling intervals for quarterly 

monitoring 

b. Reduced monitoring frequency 

c. Different IDSE sampling locations by 

disinfectant type 

d. Population-based monitoring 

requirements for certain consecutive 

systems 

3. Request for comment 

a. Proposed IDSE and Stage 2B monitoring 

requirements 

b. Plant-based vs. population-based 

monitoring requirements 

i. Issues with plant-based monitoring 

requirements 

ii. Approaches to addressing issues with 

plant-based monitoring 

J. Compliance Schedules 

1. What is EPA proposing? 

2. How did EPA develop this proposal? 

3. Request for comments 

K. Public Notice Requirements 

1. What is EPA proposing? 

2. Request for comments 

L. Variances and Exemptions 

1. Variances 

2. What are the affordable treatment 

technologies for small systems? 

M. Requirements for Systems to Use 

Qualified Operators 

N. System Reporting and Recordkeeping 

Requirements 

1. Confirmation of applicable existing 

requirements 

2. Summary of additional reporting 

requirements 

3. Request for comment 

O. Analytical Method Requirements 

1. What is EPA proposing today? 

2. How was this proposal developed? 

3. Which new methods are proposed for 

approval? 

a. EPA Method 327.0 for chlorine dioxide 

and chlorite. 

b. EPA Method 552.3 for HAA5 and 

dalapon 

c. ASTM D 6581–00 for bromate, chlorite, 

and bromide 

d. EPA Method 317.0 revision 2 for 

bromate, chlorite, and bromide 

e. EPA Method 326.0 for bromate, chlorite, 

and bromide 

f. EPA Method 321.8 for bromate 

g. EPA 415.3 for TOC and SUVA (DOC and 

UV254) 

4. What additional regulated contaminants 

can be monitored by extending approval 

of EPA Method 300.1? 

5. Which methods in the 20th edition and 

2003 On-Line Version of Standard 

Methods are proposed for approval? 

6. What is the updated citation for EPA 

Method 300.1? 

7. How is the HAA5 sample holding time 

being standardized? 

8. How is EPA clarifying which methods 

are approved for magnesium 

determinations? 

9. Which methods can be used to 

demonstrate eligibility for reduced 

bromate monitoring? 

10. Request for comments 

P. Laboratory Certification and Approval 

1. What is EPA proposing today? 

2. What changes are proposed for the PE 

acceptance criteria? 

3. What minimum reporting limits are 

being proposed? 

4. What are the requirements for analyzing 

IDSE samples? 

5. Request for comments 

VI. State Implementation 

A. State Primacy Requirements for 

Implementation Flexibility 

B. State Recordkeeping Requirements 

C. State Reporting Requirements 

D. Interim Primacy 

E. IDSE Implementation 

F. State Burden 

VII. Economic Analysis 

A. Regulatory Alternatives Considered by 

the Agency 

B. Rationale for the Proposed Rule Option 

1. Reducing peak exposure 

2. Reducing average exposure 

C. Benefits of the Proposed Stage 2 DBPR 

1. Non-quantifiable health and non-health 

related benefits 

2. Quantifiable health benefits 

3. Benefit sensitivity analyses 

D. Costs of the Proposed Stage 2 DBPR 

1. National cost estimates 

2. Water system costs 

3. State costs 

4. Non-quantifiable 

E. Expected System Treatment Changes 

1. Pre-Stage 2 DBPR baseline conditions 

2. Predicted technology distributions postStage 2 DBPR 

F. Estimated Household Costs of the 

Proposed Rule 

G. Incremental Costs and Benefits of the 

Proposed Stage 2 DBPR 

H. Benefits From the Reduction of CoOccurring Contaminants

49552 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

I. Are there Increased Risks From Other 

Contaminants? 

J. Effects on General Population and 

Subpopulation Groups 

K. Uncertainties in Baseline, Risk, Benefit, 

and Cost Estimates 

L. Benefit/Cost Determination for the 

Proposed Stage 2 DBPR 

M. Request for Comment 

VIII. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

E. Executive Order 13132: Federalism 

F. Executive Order 13175: Consultation 

and Coordination with Indian Tribal 

Governments 

G. Executive Order 13045: Protection of 

Children from Environmental Health and 

Safety Risks 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and 

Advancement Act 

J. Executive Order 12898: Federal Actions 

to Address Environmental Justice in 

Minority Populations or Low Income 

Populations 

K. Consultations with the Science 

Advisory Board, National Drinking 

Water Advisory Council, and the 

Secretary of Health and Human Services 

L. Plain Language 

IX. References

I. Summary 

A. Why Is EPA Proposing the Stage 2 

DBPR? 

The Environmental Protection Agency 

is committed to ensuring that all public 

water systems provide clean and safe 

drinking water. Disinfectants are often 

an essential element of drinking water 

treatment because of the barrier they 

provide against harmful waterborne 

microbial pathogens. However, 

disinfectants react with naturally 

occurring organic and inorganic matter 

in source water and distribution systems 

to form disinfection byproducts (DBPs) 

that may pose health risks. The Agency 

is proposing the Stage 2 Disinfectants 

and Disinfection Byproduct Rule 

(DBPR) to reduce potential cancer, 

reproductive, and developmental risks 

from DBPs. 

The Stage 2 DBPR augments the Stage 

1 DBPR that was finalized in 1998. The 

proposed Stage 2 DBPR focuses on 

monitoring and reducing concentrations 

of two classes of DBPs: total 

trihalomethanes (TTHM) and haloacetic 

acids (HAA5). In part, these two groups 

of DBPs are used as indicators of the 

various byproducts that are present in 

disinfected water. This means that 

concentrations of TTHM and HAA5 are 

monitored for compliance, but their 

presence in drinking water is 

representative of many other DBPs that 

may also be present in the water; 

likewise, a reduction in TTHM and 

HAA5 indicates a reduction of total 

DBPs. 

The Stage 2 DBPR is designed to 

reduce the level of exposure from 

disinfectants and DBPs without 

undermining the control of microbial 

pathogens. The Long Term 2 Enhanced 

Surface Water Treatment Rule 

(LT2ESWTR) will be finalized and 

implemented simultaneously with the 

Stage 2 DBPR to ensure that drinking 

water is microbiologically safe at the 

limits set for disinfectants and DBPs. 

New information on health effects, 

occurrence, and treatment has become 

available since the Stage 1 DBPR, which 

supports the need for the Stage 2 DBPR. 

Several reproductive and developmental 

studies have recently become available, 

and EPA has completed a more 

extensive analysis of reproductive and 

developmental effects associated with 

DBPs since the Stage 1 DBPR. Both 

human epidemiology studies and 

animal toxicology studies have shown 

associations between chlorinated 

drinking water and reproductive and 

developmental endpoints such as 

spontaneous abortion, stillbirth, neural 

tube defects, pre-term delivery, 

intrauterine growth retardation, and low 

birth weight. New epidemiology and 

toxicology studies evaluating bladder 

and rectal cancers have also increased 

the weight of evidence linking these 

health effects to DBP exposure. The 

large number of people (254 million 

Americans) exposed to DBPs and the 

identified potential cancer, 

reproductive, and developmental risks 

played a significant role in EPA’s 

decision to move forward with 

regulatory changes that target lowering 

DBP exposures beyond the requirements 

of the Stage 1 DBPR. 

While the Stage 1 DBPR provided a 

major reduction in DBP exposure, new 

national survey data suggest that some 

customers are receiving drinking water 

with elevated, or peak DBP 

concentrations even when their 

distribution systems are in compliance 

with the Stage 1 DBPR. Some of these 

peak concentrations can be substantially 

greater than the Stage 1 DBPR maximum 

contaminant levels (MCLs). The new 

survey results also showed that Stage 1 

DBPR monitoring sites may not be 

representative of peak DBP 

concentrations that occur in distribution 

systems. In addition, the new 

information indicates that cost-effective 

technologies including ultraviolet light 

(UV) and granular activated carbon 

(GAC) may be very effective at lowering 

DBP levels. EPA’s analysis of this new 

information concludes that significant 

public health benefits may be achieved 

through further cost-effective reduction 

of DBPs in distribution systems. 

Congress required EPA to promulgate 

the Stage 2 DBPR as part of the 1996 

Safe Drinking Water Act (SDWA) 

Amendments (section 1412(b)(2)(C)). 

Today’s proposal reflects consensus 

recommendations from the Stage 2 

Microbial/Disinfection Byproducts (MDBP) Federal Advisory Committee (the 

Advisory Committee). These 

recommendations are set forth in the MDBP Agreement in Principle (USEPA 

2000g), which can be accessed on the 

edocket Web site (www.epa.gov/

edocket). 

After considering the new occurrence 

and health effects data and analyses, 

EPA has determined that there is an 

opportunity to further reduce potential 

risks from DBPs. The Stage 2 DBPR 

being proposed today presents a costeffective, risk targeting approach to 

reduce risks from DBPs. The new 

requirements provide for more 

consistent protection from DBPs across 

the entire distribution system and the 

reduction of DBP peaks. New risk 

targeting provisions require only those 

systems with the greatest risk to make 

capital improvements. The Stage 2 

DBPR, in conjunction with the 

LT2ESWTR, will help public water 

systems deliver safer water to 

Americans with the benefits of 

disinfection to control pathogens but 

with fewer risks from DBPs. 

B. What Does the Stage 2 DBPR Require? 

The Stage 2 DBPR applies to 

community or nontransient 

noncommunity water systems that add 

a primary or residual disinfectant other 

than ultraviolet light or deliver water 

that has been treated with a primary or 

residual disinfectant other than 

ultraviolet light. The TTHM and HAA5 

MCL values will remain the same as in 

the Stage 1 DBPR, although compliance 

calculations will be different. The 

proposed Stage 2 DBPR includes new 

MCLGs for chloroform, 

monochloroacetic acid, and 

trichloroacetic acid, but these new 

MCLGs do not affect the MCLs for 

TTHM or HAA5. 

The risk targeting components of the 

Stage 2 DBPR will focus the greatest 

amount of change where the greatest 

amount of risk may exist. The 

provisions of the Stage 2 DBPR focus on 

identifying and reducing exposure by 

reducing DBP peaks in distribution 

systems. The first provision, designed to 

address significant variations in 

exposure, is the Initial Distribution 

System Evaluation (IDSE). The purpose

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49553

of the IDSE is to identify Stage 2 DBPR 

compliance monitoring sites for 

capturing peaks. Because Stage 2 DBPR 

compliance will be determined at these 

new monitoring sites, distribution 

systems that identify elevated 

concentrations of TTHM and HAA5 will 

need to make treatment or process 

changes to bring the system into 

compliance with the Stage 2 DBPR. By 

identifying compliance monitoring sites 

with elevated concentrations of TTHM 

and HAA5, the IDSE will offer increased 

assurance that MCLs are being met 

across the distribution system. Both 

treatment changes and awareness of 

TTHM and HAA5 levels resulting from 

the IDSE will allow systems to better 

control for distribution system peaks. 

The IDSE is designed to offer 

flexibility to public water systems. The 

IDSE requires TTHM and HAA5 

monitoring for one year on a regular 

schedule that is determined by source 

water type and system size. Systems 

have the option of performing a sitespecific study based on historical data, 

water distribution system models, or 

other data; and waivers are available 

under certain circumstances. The 

proposed IDSE requirements are 

discussed in sections V.H., V.I., and V.J. 

of this preamble and in subpart U of the 

proposed rule. 

The second provision of the Stage 2 

DBPR, which is designed to address 

variations in temporal and spatial 

exposure, is the new compliance 

calculation of the MCLs. The Stage 1 

DBPR running annual average (RAA) 

calculation allows some locations 

within a distribution system to have 

higher DBP annual averages than others 

as long as the system-wide average is 

below the MCL. The Stage 2 DBPR will 

base compliance on a locational running 

annual average (LRAA) calculation 

where the annual average at each 

sampling location in the distribution 

system will be used to determine 

compliance with the MCLs. The LRAA 

will reduce exposures to peak DBP 

concentrations by ensuring that each 

monitoring site is in compliance with 

the MCLs as an annual average, and it 

will provide all customers drinking 

water that more consistently meets the 

MCLs. 

EPA is proposing that systems comply 

with the Stage 2 DBPR MCLs in two 

phases, designated as Stage 2A and 

Stage 2B. In Stage 2A, beginning three 

years after the rule is final, all systems 

must comply with MCLs of 0.120 mg/L 

for TTHM and 0.100 mg/L for HAA5 as 

LRAAs at Stage 1 DBPR sampling sites, 

in addition to continuing to comply 

with the Stage 1 DBPR MCLs of 0.080 

mg/L and 0.060 mg/L as RAAs for 

TTHM and HAA5, respectively. In Stage 

2B, systems must comply with MCLs of 

0.080 mg/L and 0.060 mg/L as LRAAs 

for TTHM and HAA5, respectively, 

based on sampling sites identified 

through the IDSE. A more detailed 

discussion of the proposed Stage 2 

DBPR MCL requirements can be found 

in sections V.D., V.I., and V.J. of this 

preamble and in § 141.64(b)(2) and (3), 

and § 141.136, and subpart V of the rule 

language.

The IDSE and LRAA calculation will 

lead to overall reductions in DBP 

concentrations and reduce short term 

exposures to high DBP concentrations, 

but even with this strengthened 

approach to regulating DBPs it will be 

possible for individual DBP samples to 

exceed the MCLs when systems are in 

compliance with the Stage 2 DBPR. The 

Stage 2 DBPR requires systems that 

experience significant excursions to 

evaluate distribution system operational 

practices and identify opportunities to 

reduce DBP concentrations in the 

distribution system. This provision will 

curtail peaks and reduce exposure to 

high DBP levels. Significant excursions 

are discussed in greater detail in section 

V.E. 

The Stage 2 DBPR also contains 

provisions for regulating consecutive 

systems, defined in the Stage 2 DBPR as 

public water systems that buy or 

otherwise receive some or all of their 

finished water from another public 

water system on a regular basis. 

Uniform regulation of consecutive 

systems provided by the Stage 2 DBPR 

will ensure that consecutive systems 

deliver drinking water that meets 

applicable DBP standards. More 

information on regulation of 

consecutive systems can be found in 

sections V.C., V.H., V.I. and V.J. 

Today’s document proposes plantbased monitoring requirements for nonconsecutive systems and certain 

consecutive systems. Plant-based 

monitoring means that the number of 

compliance monitoring locations within 

a distribution system is based on the 

number of plants, population served, 

and type of source water used by the 

distribution system. EPA is proposing 

population-based monitoring for 

consecutive systems that buy all their 

finished water from other public water 

systems. EPA is also requesting 

comment on whether this approach 

should be extended to all systems 

covered by today’s rule. Under a 

population-based monitoring structure, 

the number of compliance monitoring 

locations is based only on the 

population served and source water 

type. Section V.I. describes populationbased monitoring and how it might 

affect systems complying with this rule. 

C. What Are the Economic Impacts of 

the Stage 2 DBPR? 

EPA quantified the potential benefits 

of the Stage 2 DBPR by estimating the 

reduction in bladder cancer cases that 

may result from the decrease in average 

DBP concentrations in disinfected 

water. Estimated reductions in DBPrelated bladder cancers (including both 

fatal and non-fatal cases) result in 

annualized benefits ranging from $0 to 

$986 million (using a three percent 

discount rate), depending on the risk 

level assumed. 

There may also be a number of 

important nonquantifiable benefits 

associated with reducing DBPs in 

drinking water, the primary ones being 

reduced potential risk of adverse 

reproductive and developmental effects 

including miscarriage, stillbirth, neural 

tube defects, heart defects, and cleft 

palate. Although a number of studies 

have found an association between 

reproductive and developmental 

endpoints and short-term exposure to 

elevated DBP levels, a causal link has 

not yet been established and 

information is not yet available to 

quantify potential effects. As a result, 

the Agency has not included an estimate 

of the potential benefits from reducing 

reproductive and developmental risks in 

its primary economic impact analysis of 

the Stage 2 DBPR. However, an 

illustrative calculation of potential fetal 

loss risk is discussed in Section VII and 

presented in more detail in the 

Economic Analysis (USEPA 2003i) to 

illustrate the benefits that could be 

associated with this rule. Reduction in 

other cancers potentially associated 

with DBP exposure represent additional 

unquantified health benefits.

EPA estimates the total annualized 

costs of the Stage 2 DBPR to be $54 to 

$64 million. This estimate includes 

costs associated with treatment changes, 

the Initial Distribution System 

Evaluation, changes in compliance 

monitoring, and rule implementation 

activities for both public water systems 

and States. EPA estimates that 

approximately 2.8 percent of all plants 

will need to convert to chloramines or 

add advanced treatment to comply with 

the Stage 2 DBPR. 

Table I–1 presents the estimated 

quantified and unquantified benefits of 

the Stage 2 DBPR and the estimated 

costs. Analyses of unquantified benefits 

suggest that the total benefits associated 

with the Stage 2 DBPR might be much 

greater than these estimates. By 

targeting risks and building on the solid 

foundation of the Stage 1 DBPR, the

49554 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

Stage 2 DBPR will deliver cost-effective reductions in DBP levels and associated 

potential public health risks.

TABLE I–1.—COSTS AND BENEFITS OF THE STAGE 2 DBPR BASED ON ANNUALIZATION DISCOUNT RATE OF 3% 

Costs Benefits Unquantified benefits 

$54–64 M ....................... $0–986 M Reduction in potential reproductive and developmental health effects, potential reduction in colon 

and rectal cancer, improved taste and odor of drinking water, control of contaminants that may be 

regulated in the future. 

II. Background 

A combination of factors have 

influenced the development of the 

proposed Stage 2 DBPR. These include 

the initial 1992–1994 Microbial and 

Disinfection Byproduct (M–DBP) 

stakeholder deliberations and EPA’s 

Stage 1 DBPR proposal; the 1996 Safe 

Drinking Water Act (SDWA) 

Amendments; the 1996 Information 

Collection Rule; the 1998 Stage 1 DBPR; 

other new data, research, and analysis 

on disinfection byproduct (DBP) 

occurrence, treatment, and health effects 

since the Stage 1 DBPR; and the Stage 

2 DBPR Microbial and Disinfection 

Byproducts Federal Advisory 

Committee. The following shows how 

EPA arrived at this proposal for 

regulating disinfection byproducts. 

A. What Is the Statutory Authority for 

the Stage 2 DBPR? 

The SDWA, as amended in 1996, 

authorizes EPA to promulgate a national 

primary drinking water regulation 

(NPDWR) and publish a maximum 

contaminant level goal (MCLG) for 

contaminants the Administrator 

determines ‘‘may have an adverse effect 

on the health of persons,’’ is ‘‘known to 

occur or there is a substantial likelihood 

that the contaminant will occur in 

public water systems with a frequency 

and at levels of public health concern,’’

and for which ‘‘in the sole judgement of 

the Administrator, regulation of such 

contaminant presents a meaningful 

opportunity for health risk reduction for 

persons served by public water 

systems’’ (SDWA section 1412(b)(1)(A)). 

MCLGs are non-enforceable health goals 

set at a level at which ‘‘no known or 

anticipated adverse effects on the health 

of persons occur and which allows an 

adequate margin of safety’’. These 

health goals are published at the same 

time as the NPDWR (sections 1412(b)(4) 

and 1412(a)(3)). 

The Agency may also consider 

additional health risks from other 

contaminants and establish an MCL ‘‘at 

a level other than the feasible level, if 

the technology, treatment techniques, 

and other means used to determine the 

feasible level would result in an 

increase in the health risk from drinking 

water by—(i) increasing the 

concentration of other contaminants in 

drinking water; or (ii) interfering with 

the efficacy of drinking water treatment 

techniques or processes that are used to 

comply with other national primary 

drinking water regulations’’ (section 

1412(b)(5)(A)). When establishing an 

MCL or treatment technique under this 

authority, ‘‘the level or levels of 

treatment techniques shall minimize the 

overall risk of adverse health effects by 

balancing the risk from the contaminant 

and the risk from other contaminants 

the concentrations of which may be 

affected by the use of a treatment 

technique or process that would be 

employed to attain the MCL or levels’’

(section 1412(b)(5)(B)). 

Finally, section 1412(b)(2)(C) of the 

Act requires EPA to promulgate a Stage 

2 DBPR 18 months after promulgation of 

the Long Term 1 Enhanced Surface 

Water Treatment Rule (LT1ESWTR). 

Consistent with statutory requirements 

for risk balancing (section 

1412(b)(5)(B)), EPA will finalize the 

LT2ESWTR concurrently with the Stage 

2 DBPR to ensure simultaneous 

protection from microbial and DBP 

risks. 

B. What Is the Regulatory History of the 

Stage 2 DBPR? 

The first rule to regulate DBPs was 

promulgated on November 29, 1979. 

The Total Trihalomethanes Rule (44 FR 

68624) (USEPA 1979) set an MCL of 

0.10 mg/L for total trihalomethanes 

(TTHMs). Compliance was based on the 

running annual average (RAA) of 

quarterly averages of all samples 

collected throughout the distribution 

system. This TTHM standard applied 

only to community water systems using 

surface water and/or ground water that 

served at least 10,000 people and added 

a disinfectant to the drinking water 

during any part of the treatment process. 

Under the Surface Water Treatment 

Rule (SWTR) (54 FR 27486, June 29, 

1989) (USEPA 1989a), EPA set MCLGs 

of zero for Giardia lamblia, viruses, and 

Legionella; and promulgated NPDWRs 

for all public water systems using 

surface water sources or ground water 

sources under the direct influence of 

surface water. The SWTR includes 

treatment technique requirements for 

filtered and unfiltered systems that are 

intended to protect against the adverse 

health effects of exposure to Giardia 

lamblia, viruses, and Legionella, as well 

as other pathogenic organisms. 

EPA also promulgated the Total 

Coliform Rule (TCR) on June 29, 1989 

(54 FR 27544)(USEPA 1989b) to provide 

protection from microbial 

contamination in distribution systems of 

all types of public water supplies. The 

TCR established an MCLG of zero for 

total and fecal coliform bacteria, and an 

MCL based on the percentage of positive 

samples collected during a compliance 

period. Under the TCR, no more than 5 

percent of distribution system samples 

collected in any month may contain 

coliform bacteria. 

Together, the SWTR and the TCR 

were intended to address risks 

associated with microbial pathogens 

that might be found in source waters or 

associated with distribution systems. 

However, while reducing exposure to 

pathogenic organisms, the SWTR also 

increased the use of disinfectants in 

some public water systems and, as a 

result, exposure to DBPs in those 

systems. 

In 1992, prompted by concerns about 

health risk tradeoffs between 

disinfection byproducts and microbial 

pathogens, EPA initiated a negotiated 

rulemaking with a wide range of 

stakeholders. The negotiators included 

representatives of State and local health 

and regulatory agencies, public water 

systems, elected officials, consumer 

groups, and environmental groups. The 

Regulatory Negotiating Committee met 

from November 1992 through June 1993. 

Following months of intensive 

discussions and technical analyses, the 

Regulatory Negotiating Committee 

recommended the development of three 

sets of rules: an Information Collection 

Rule, a two-staged approach for 

regulating DBPs, and an ‘‘interim’’

Enhanced Surface Water Treatment Rule 

(IESWTR) to be followed by a ‘‘final’’

Enhanced Surface Water Treatment Rule 

(USEPA 1996a, USEPA 1998c, USEPA 

1998d). EPA took the first step towards 

implementing this strategy by proposing

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49555

the Stage 1 DBPR and IESWTR in 1994. 

Congress affirmed the phased microbial 

and disinfection byproduct rulemaking 

strategy in the 1996 SDWA 

Amendments by requiring that EPA 

develop these three sets of rules on a 

specific schedule that stipulates 

simultaneous promulgation of 

requirements governing microbial 

protection and DBPs.

In March 1997, the Agency 

established the Microbial and 

Disinfection Byproduct (M–DBP) 

Advisory Committee under the Federal 

Advisory Committee Act (FACA) to 

collect, share, and analyze new 

information and data available since the 

1994 proposals of the Stage 1 DBPR and 

the IESWTR, as well as to build 

consensus on the regulatory 

implications of the new information. 

The Advisory Committee consisted of 

17 members representing EPA, State and 

local public health and regulatory 

agencies, local elected officials, drinking 

water suppliers, chemical and 

equipment manufacturers, and public 

interest groups. The Advisory 

Committee met five times in March 

through July 1997 to discuss issues 

related to the IESWTR and the Stage 1 

DBPR. The Advisory Committee reached 

consensus on a number of major issues 

that were incorporated into the Stage 1 

DBPR and the IESWTR. 

The Stage 1 DBPR and IESWTR, 

finalized in December 1998, were the 

first rules to be promulgated under the 

1996 SDWA Amendments (USEPA 

1998c and 1998d). The Stage 1 DBPR 

applies to all community and 

nontransient noncommunity water 

systems that add a chemical disinfectant 

to water. The rule established maximum 

residual disinfectant level goals 

(MRDLGs) and enforceable maximum 

residual disinfectant level (MRDL) 

standards for three chemical 

disinfectants—chlorine, chloramine, 

and chlorine dioxide; maximum 

contaminant level goals (MCLGs) for 

three THMs, two haloacetic acids 

(HAAs), bromate, and chlorite; and 

enforceable maximum contaminant 

level (MCL) standards for TTHM, five 

haloacetic acids (HAA5), chlorite, and 

bromate calculated as running annual 

averages (RAAs). The Stage 1 DBPR uses 

TTHMs and HAA5 as indicators of the 

various DBPs that are present in 

disinfected water. Under the Stage 1 

DBPR, water systems that use surface 

water or ground water under the direct 

influence of surface water and use 

conventional filtration treatment are 

required to remove specified 

percentages of organic materials, 

measured as total organic carbon (TOC), 

that may react with disinfectants to form 

DBPs. Removal is achieved through 

enhanced coagulation or enhanced 

softening, unless a system meets 

alternative compliance criteria. 

EPA finalized the IESWTR at the same 

time as the Stage 1 DBPR to ensure 

simultaneous compliance and address 

risk tradeoff issues. The IESWTR 

applies to all water systems that use 

surface water or ground water under the 

direct influence of surface water that 

serve at least 10,000 people. The 

purpose of the IESWTR is to improve 

control of microbial pathogens in 

drinking water, specifically the 

protozoan Cryptosporidium.

The Filter Backwash Recycle Rule 

(FBRR) and the Long Term 1 Enhanced 

Surface Water Treatment Rule 

(LT1ESWTR) round out the first group 

of regulations balancing microbial and 

DBP risks. EPA promulgated the FBRR 

in 2001 (USEPA 2001c) and the 

LT1ESWTR in 2002 (USEPA 2002b) to 

increase protection of finished drinking 

water supplies from contamination by 

Cryptosporidium and other microbial 

pathogens. The LT1ESWTR extends 

protection against Cryptosporidium and 

other disease-causing microbes to water 

systems that use surface water or ground 

water under the direct influence of 

surface water that serve fewer than 

10,000 people. While the Ground Water 

Rule, proposed in May 2000, (USEPA 

2000h) will add significant protection 

from pathogens in vulnerable ground 

water systems, it does not pose as many 

risk-risk tradeoff considerations as the 

surface water rules because only a small 

percentage of ground water systems 

subject to the Stage 2 DBPR have high 

DBP levels. 

EPA reconvened the Advisory 

Committee in March 1999 to develop 

recommendations on issues pertaining 

to the Stage 2 DBPR and LT2ESWTR. 

The Advisory Committee collected, 

developed, and evaluated new 

information that became available after 

the Stage 1 DBPR was published. The 

Information Collection Rule provided 

new data on DBP exposure, and control; 

it also included new data on occurrence 

and treatment of pathogens. The 

unprecedented amount of information 

collected under the Information 

Collection Rule was supplemented by a 

survey conducted by the National Rural 

Water Association, data provided by 

various States, the Water Utility 

Database (which contains data collected 

by the American Water Works 

Association), and Information 

Collection Rule Supplemental Surveys. 

This large body of data allowed the 

Advisory Committee to reach new 

conclusions regarding DBP exposure 

and new treatment options. 

After analyzing the data, the Advisory 

Committee reached three significant 

conclusions that led the Advisory 

Committee to recommending further 

control of DBPs in public water systems. 

The data from the Information 

Collection Rule show that the RAA 

compliance calculation allows elevated 

DBP levels to regularly occur at some 

locations in the system when the overall 

average at all locations is below the 

MCL. Customers served at those 

sampling locations that regularly exceed 

the MCLs are experiencing higher 

exposure compared to customers served 

at locations that consistently meet the 

MCLs. 

Second, the new data demonstrated 

how single samples can be substantially 

above the MCLs. The new information 

showed that it is possible for customers 

to receive drinking water with 

concentrations of DBPs up to 75% above 

the MCLs even when their water system 

is in compliance with the Stage 1 DBPR. 

Studies have shown that DBP exposure 

during short, critical time windows may 

adversely impact reproductive and 

developmental health. 

Third, data from the Information 

Collection Rule revealed that the highest 

TTHM and HAA5 levels are not always 

located at the maximum residence time 

monitoring sites specified by the Stage 

1 DBPR. These sites were required for 

monitoring by the Stage 1 DBPR because 

previous data suggested that water in 

the distribution system for the 

maximum residence time would have 

the highest TTHM levels. The fact that 

the locations with the highest DBP 

levels varied in different public water 

systems indicates that the Stage 1 DBPR 

monitoring sites may not be 

representative of the high DBP 

concentrations that actually exist in 

distribution systems, and additional 

monitoring is needed to identify 

distribution system locations with 

elevated DBP levels. This information 

encouraged the Advisory Committee to 

recommend additional measures to 

identify locations with high LRAAs. 

Section IV provides a complete 

discussion of the new occurrence data. 

The analysis of the new data also 

indicates that certain technologies are 

effective at reducing DBP 

concentrations. Bench- and pilot-scale 

studies for granular activated carbon 

(GAC) and membrane technologies 

required by the Information Collection 

Rule provided information on the 

effectiveness of the two technologies. 

Other studies found UV light to be 

highly effective for inactivating 

Cryptosporidium and Giardia at low 

doses without promoting the formation 

of DBPs (Malley et al. 1996; Zheng et al.

49556 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

1999). This new treatment information 

added to the treatment options available 

to utilities for controlling DBPs beyond 

the requirements of the Stage 1 DBPR. 

New data on the health effects of 

DBPs also influenced the Advisory 

Committee’s recommendation to further 

regulate DBPs. Although bladder cancer 

risks were the focus of the Stage 1 M–

DBP negotiations, potential 

reproductive and developmental health 

effects were central to the Stage 2 M–

DBP Advisory Committee discussions. 

Recent human epidemiology studies 

and animal toxicology studies have both 

shown associations between chlorinated 

drinking water and reproductive and 

developmental health effects such as 

spontaneous abortion, stillbirth, neural 

tube defects, pre-term delivery, 

intrauterine growth retardation, and low 

birth weight. A critical review of the 

epidemiology literature pertaining to 

reproductive and developmental effects 

of exposure to DBPs completed in 2000 

(Reif et al. 2000) concluded that ‘‘the 

weight of evidence from the 

epidemiological studies also suggests 

that they [DBPs] are likely to be 

reproductive toxicants in humans under 

appropriate exposure conditions * * * 

and that measures aimed at reducing the 

concentrations of byproducts could 

have a positive impact on public 

health.’’

While there has been substantial 

research to date, the Advisory 

Committee recognized that significant 

uncertainty remains regarding the risk 

associated with DBPs in drinking water. 

The Advisory Committee carefully 

considered the analyses described 

previously, as well as costs and 

potential impacts on public water 

systems, and concluded that a targeted 

protective public health approach 

should be taken to address exposure to 

DBPs beyond the requirements of the 

Stage 1 DBPR. After reaching this 

conclusion, the Advisory Committee 

developed an Agreement in Principle 

(USEPA 2000g) that laid out their 

recommendations on how to further 

control DBPs in public water systems.

In the Agreement in Principle, the 

Advisory Committee recommended 

maintaining the MCLs for TTHM and 

HAA5 at 0.080 mg/L and 0.060 mg/L 

respectively, but changing the 

compliance calculation in two phases to 

facilitate systems moving from the 

running annual average (RAA) 

calculation to a locational running 

annual average (LRAA) calculation. In 

the first phase, systems would continue 

to comply with the Stage 1 DBPR MCLs 

as RAAs and, at the same time, comply 

with MCLs of 0.120 mg/L for TTHM and 

0.100 mg/L for HAA5 calculated as 

LRAAs. RAA calculations average all 

samples collected within a distribution 

system over a one-year period, but 

LRAA calculations average all samples 

taken at each individual sampling 

location in a distribution system during 

a one-year period. Systems would also 

carry out an Initial Distribution System 

Evaluation (IDSE) to select new 

compliance monitoring sites that more 

accurately reflect higher TTHM and 

HAA5 levels occurring in the 

distribution system. The second phase 

of compliance would require MCLs of 

0.080 mg/L for TTHM and 0.060 mg/L 

for HAA5 calculated as LRAAs at 

individual monitoring sites identified 

through the IDSE. 

The Agreement in Principle also 

provided recommendations for 

simultaneous compliance with the 

LT2ESWTR so that the reduction of 

potential health hazards of DBPs does 

not compromise microbial protection. 

The recommendations for the 

LT2ESWTR included treatment 

requirements for Cryptosporidium based 

on the results of source water 

monitoring, a toolbox of options for 

providing additional treatment at high 

risk facilities, use of microbial 

indicators to reduce Cryptosporidium

monitoring burden on small systems, 

and future monitoring to determine if 

source water quality remains constant 

after completion of initial monitoring. 

The Agreement also encouraged EPA to 

develop guidance and criteria to 

facilitate the use of UV light for 

compliance with drinking water 

disinfection requirements. The complete 

text of the Agreement in Principle 

(USEPA 2000g) can be found at the 

edocket Web site (http://www.epa.gov/

edocket).

After extensive analysis and 

investigation of available data and rule 

options considered by the Advisory 

Committee, EPA is proposing a Stage 2 

DBPR control strategy that is consistent 

with the key elements of the Agreement 

in Principle signed in September 2000 

by the participants in the Stage 2 M–

DBP Advisory Committee. EPA 

determined that the risk-targeting 

measures recommended in the 

Agreement in Principle will require 

only those systems with the greatest risk 

to make treatment and operational 

changes and will maintain simultaneous 

protection from the potential health 

hazards of DBPs and microbial 

contaminants. EPA has carefully 

evaluated and expanded upon the 

recommendations of the Advisory 

Committee to more fully develop 

today’s proposal. EPA also made 

simplifications where possible to 

minimize complications for public 

water systems as they transition to 

compliance with the Stage 2 DBPR 

while expanding public health 

protection. The proposed requirements 

of the Stage 2 DBPR are described in 

detail in section V of this preamble. 

C. How Were Stakeholders Involved in 

Developing the Stage 2 DBPR? 

1. Federal Advisory Committee Process 

The Stage 2 M–DBP Advisory 

Committee consisted of 21 

organizational members representing 

EPA, State and local public health and 

regulatory agencies, local elected 

officials, Native American Tribes, large 

and small drinking water suppliers, 

chemical and equipment manufacturers, 

environmental groups, and other 

stakeholders. Technical support for the 

Advisory Committee’s discussions was 

provided by a technical working group 

established by the Advisory Committee. 

The Advisory Committee held ten 

meetings to discuss issues pertaining to 

the Stage 2 DBPR and LT2ESWTR from 

September 1999 to July 2000 which 

were open to the public. There was also 

an opportunity for public comment at 

each meeting. 

In September 2000, the Advisory 

Committee signed the Agreement in 

Principle, a full statement of the 

consensus recommendations of the 

group. The agreement was published by 

EPA in a December 29, 2000 Federal 

Register notice (65 FR 83015), together 

with the list of committee members and 

their organizations. The Agreement is 

divided into Parts A and B. The 

recommendations in each part stand 

alone and are independent of one 

another. The entire Advisory Committee 

reached consensus on Part A, which 

contains provisions that directly apply 

to the proposed Stage 2 DBPR and 

LT2ESWTR. The full Advisory 

Committee, with the exception of the 

National Rural Water Association 

(NRWA), also agreed to Part B, which 

has recommendations for future 

activities by EPA in the areas of 

distribution systems and microbial 

water quality criteria. 

2. Other Outreach Processes 

EPA received valuable input from 

small system operators as part of an 

Agency outreach initiative under the 

Regulatory Flexibility Act (RFA). EPA 

also conducted outreach conference 

calls to solicit feedback and information 

from Small Entity Representatives 

(SERs) on issues related to Stage 2 DBPR 

impacts on small systems. The Agency 

consulted with State, local, and Tribal 

governments on the proposed Stage 2 

DBPR. Section VIII includes a complete

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49557

description of the many stakeholder 

activities which contributed to the 

development of the Stage 2 DBPR.

The Agency held two meetings to 

discuss consecutive system issues 

relevant to the proposal (February 22–

23, 2001 in Denver, CO and March 28, 

2001 in Washington, DC). 

Representatives from States, EPA 

Regions, and public water systems 

participated in the discussions. EPA 

also briefed the National Drinking Water 

Advisory Committee at their November 

2001 meeting on consecutive system 

issues associated with the rule to 

receive input on the implementation 

strategy selected. This Advisory 

Committee generally supported EPA’s 

approach. Section V describes EPA’s 

analysis of consecutive system issues, 

comments and input received during 

these sessions, and how the proposed 

requirements will apply to consecutive 

systems. EPA also consulted with the 

Science Advisory Board in December 

2001 on the requirements of the Stage 2 

DBPR. 

Finally, EPA posted a pre-proposal 

draft of the Stage 2 DBPR preamble and 

regulatory language on an EPA Internet 

site (http://www.epa.gov/safewater/

mdbp/st2dis.html) on October 17, 2001. 

This public review period allowed 

readers to comment on the Stage 2 

DBPR’s consistency with the Agreement 

in Principle of the Stage 2 M–DBP 

Advisory Committee. EPA received 

important suggestions on this preproposal draft from 14 commenters 

which included public water systems, 

State governments, laboratories, and 

other stakeholders. While EPA will not 

formally respond to these comments, 

EPA has carefully considered them in 

developing today’s proposal. 

III. Public Health Risk 

Chlorine has been widely used as a 

chemical disinfectant, serving as a 

principal barrier to microbial 

contaminants in drinking water. 

However, the microbial risk reduction 

attributes of chlorination have been 

increasingly scrutinized due to concerns 

about potential increased health risks 

from exposure to disinfection 

byproducts, which are formed when 

certain disinfectants interact with 

organic and inorganic material in source 

waters. Since the discovery of 

chlorination byproducts in drinking 

water in 1974, numerous toxicological 

studies have shown several DBPs (e.g., 

bromodichloromethane, bromoform, 

chloroform, dichloroacetic acid, 

trichloroacetic acid and bromate) to be 

carcinogenic in laboratory animals. 

These findings of carcinogenicity 

influenced EPA to promulgate the 

TTHM Rule in 1979 and the Stage 1 

DBPR in 1998. The Stage 1 DBPR 

primarily addressed possible 

carcinogenic effects (e.g., bladder, colon 

and rectal cancers) reported in both 

human epidemiology and laboratory 

animal studies. Since the Stage 1 DBPR, 

new health studies continue to support 

an association between bladder, colon 

and rectal cancers from long-term 

exposure to chlorinated surface water. 

In addition to cancer effects, recent 

studies have reported associations 

between use of chlorinated drinking 

water and a number of reproductive and 

developmental endpoints including 

spontaneous abortion, still birth, neural 

tube defect, pre-term delivery, low birth 

weight and intrauterine growth 

retardation (small for gestational age). 

Short-term, high-dose animal screening 

studies on individual byproducts (e.g., 

bromodichloromethane (BDCM), and 

certain haloacetic acids) have also 

reported adverse reproductive and 

developmental effects (e.g., whole litter 

resorption, reduced fetal body weight) 

that are similar to those reported in the 

human epidemiology studies. This 

section discusses the new studies that 

have become available since 

promulgation of the Stage 1 DBPR and 

how they contribute to the weight of 

evidence for an association between 

health effects and exposure to 

chlorinated surface water. 

While the Stage 1 DBPR was targeted 

primarily at reducing long-term 

exposures to elevated levels of DBPs to 

address chronic health risks from 

cancer, the Stage 2 DBPR targets 

reducing short-term exposures to 

address potential reproductive and 

developmental health risks and cancer 

risks. 

Based on the weight of evidence from 

both the human epidemiology and 

animal toxicology data on cancer and 

reproductive and developmental health 

effects and consideration of the large 

number of people exposed to 

chlorinated byproducts in drinking 

water (approximately 254 million), EPA 

concludes that: (1) Current reproductive 

and developmental health effects data 

support a hazard concern, (2) new 

cancer data strengthens the evidence of 

an association of chlorinated water with 

bladder cancer and suggests an 

association for colon and rectal cancers, 

and (3) the combined health data 

warrant regulatory action beyond the 

Stage 1 DBPR. 

A. Reproductive and Developmental 

Epidemiology 

The following section briefly 

discusses reproductive and 

developmental epidemiology 

information EPA analyzed, some 

conclusions of these studies and reports, 

and implications for the Stage 2 DBPR. 

Further discussion of the implications 

and EPA’s conclusions can be found in 

the Stage 2 Economic Analysis (USEPA 

2003i). 

EPA has evaluated recently published 

epidemiological studies examining the 

relationship between exposure to 

contaminants in chlorinated surface 

water and adverse reproductive and 

developmental outcomes. EPA also 

considered critical reviews of the 

epidemiological literature by Reif et al.

(2000), Bove et al. (2002), and 

Nieuwenhuijsen et al. (2000). Based on 

these evaluations, EPA believes that the 

reproductive and developmental 

epidemiology data contribute to the 

weight of evidence on the potential 

health risks from exposure to 

chlorinated drinking water. Although 

the data are not suitable for a 

quantitative risk assessment at this time, 

due in part to inconsistencies in the 

findings, they do suggest that exposure 

to DBPs is a potential reproductive and 

developmental health hazard. 

1. Reif et al. 2000 

Reif et al. (2000) completed a critical 

review of the epidemiology literature 

pertaining to reproductive and 

developmental effects of exposure to 

disinfection byproducts in drinking 

water as a report to Health Canada. The 

review focused on 16 peer-reviewed 

scientific manuscripts and published 

reports and evaluated associations 

between DBP exposure and outcomes 

grouped as effects on: (1) Fetal growth—

low birth weight (<2500g); very low 

birth weight (<1500g); preterm delivery 

(<37 weeks of gestation) and 

intrauterine growth retardation (or small 

for gestational age); (2) fetal viability 

(spontaneous abortion and stillbirth) 

and (3) fetal malformations (all 

malformations, oral cleft defects, major 

cardiac defects, neural tube defects, and 

chromosomal abnormalities). 

a. Fetal growth. Reif et al. (2000) 

found inconsistent epidemiological 

evidence for an association between 

DBPs and fetal growth. Some studies 

found weak but statistically significant 

associations (Gallagher et al. 1998; Bove 

et al. 1992 and 1995), while two studies 

found no association (Dodds et al. 1999; 

and Savitz et al. 1995) with fetal growth. 

b. Fetal viability. Reif et al. 2000’s 

review of the literature found 

inconsistencies in the epidemiological 

evidence for the association between 

DBP exposure and fetal viability. For 

instance, the study by Waller et al. 1998 

found an apparent dose-dependent 

increase in rates of spontaneous

49558 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

abortions associated with TTHMs in 

California. On the other hand, Savitz et 

al. (1995) found little evidence of an 

association using either the 

concentration of TTHM ≥81 μg/L or a 

dose estimate based on the amount of 

tap water consumed. An increased risk 

of stillbirth was reported for women in 

Nova Scotia by Dodds et al. 1999, but 

in New Jersey, Bove et al. (1992, 1995) 

found little evidence of an association 

with TTHM at 80 μg/L, but did report 

a weak association between stillbirth 

and use of surface water systems. 

Aschengrau et al. (1993) found an 

association between stillbirth and the 

use of a chlorinated vs. chloraminated 

surface water supply, but not for 

exposure to surface water. 

c. Fetal malformations and other 

developmental anomalies. Reif et al.

(2000) considered the data for 

congenital anomalies to be inconsistent 

across the six studies that have explored 

these outcomes. For example, two of the 

four studies on neural tube defects 

(Bove et al. 1995; Magnus et al. 1999) 

reported significant excess risks, but the 

remaining two studies (Dodds et al.

1999; Klotz and Pyrch et al. 1999) did 

not. These studies found lower risks or 

no evidence of an association with 

TTHM. However, those studies were 

conducted in locations with either very 

low or high concentrations of DBPs 

which may have limited the contrast in 

exposures, thereby reducing the ability 

to detect increased risks. An assessment 

of congenital anomalies is also difficult 

due to the relatively small number of 

cases available for evaluation. 

Overall, Reif et al. (2000) conclude 

that the weight of evidence from the 

epidemiological studies suggest that 

‘‘DBPs are likely to be reproductive 

toxicants in humans under appropriate 

exposure conditions.’’ Reif et al.

comment that data from animal studies 

of individual DBPs provide biological 

plausibility for the effects observed in 

epidemiological studies. Although the 

authors recognize that the ‘‘data are 

primarily at the stage of hazard 

identification,’’ they conclude that 

‘‘measures aimed at reducing the 

concentrations of byproducts could 

have a positive impact on public 

health.’’

2. Bove et al. 2002

Bove et al. (2002) conducted a 

qualitative review of 14 epidemiological 

studies that evaluated possible 

developmental and reproductive 

endpoints associated with exposure to 

chlorination byproducts in drinking 

water. Similar to Reif et al., Bove et al.

evaluated associations between DBP 

exposure and outcomes grouped as 

effects on (1) fetal growth—small for 

gestational age (SGA) as defined in each 

study (usually defined as the fifth or 

tenth percentile weight by gestational 

week of birth); (2) fetal viability—

spontaneous abortion and stillbirth; and 

(3) fetal malformations (neural tube 

defects, oral clefts, and cardiac defects). 

a. Fetal growth. Bove et al. found that, 

although the studies that evaluated SGA 

had several limitations, three studies 

out of eight (Kramer et al. 1992, Bove et 

al. 1995, and Gallagher et al. 1998) 

‘‘provided moderate evidence for a 

causal relationship between a narrow 

definition of SGA * * * and TTHM 

levels that could be found currently in 

some U.S. public water systems.’’ They 

also concluded that the study with the 

best exposure assessment found the 

strongest association between SGA and 

TTHM exposure (Gallagher et al. 1998). 

One study found a very weak 

association (Dodds et al. 1999) and the 

other four did not observe an 

association (Yang et al. 2000, Kanitz et 

al. 1996, Kallen et al. 2000, and Jaakkola 

et al. 2001). 

b. Fetal viability. Bove et al. evaluated 

three studies on spontaneous abortion 

and three studies on stillbirth. Again, 

Bove et al. found that the study 

employing the best methods found the 

strongest association between TTHM 

exposure and spontaneous abortions 

(Waller et al. 1998). The other two 

studies (Savitz et al. 1995 and 

Aschengrau et al. 1989) found weak 

associations. Two of the studies 

investigating stillbirths found an 

association between stillbirths and 

chlorinated surface water (Dodds et al.

2001 and Aschengrau et al. 1993). The 

third study (Bove et al. 1995) found no 

association, however this study did not 

evaluate individual THM levels or cause 

of death information. 

c. Fetal malformations. Bove et al.

evaluated seven studies that 

investigated the relationship between 

birth defects and DBP exposure. This 

evaluation found ‘‘consistency among 

these studies in the findings for neural 

tube defects and oral cleft defects, but 

not for cardiac defects. Associations 

were found for neural tube defects in all 

three studies that examined neural tube 

defects. These studies also evaluated 

levels of THM exposure (Bove et al.

1995; Dodds et al. 1999; Klotz et al.

1999).’’ Two studies evaluated oral cleft 

defects and levels of THMs; one found 

an association with TTHM (Bove et al.

1995) and the other found an 

association with chloroform (Dodds et 

al. 2001). A third study that did not 

evaluate THM levels did not identify an 

association with oral cleft defects 

(Jaakkola et al. 2001). Bove et al. 1995 

found an association between cardiac 

defects and TTHM, but Dodds et al.

1999, 2001 and Shaw et al. 1991 did 

not. An association between 

chlorination and urinary tract defects 

was found in the three studies that 

evaluated that endpoint (Ka ̈lle ́n et al.

2000; Magnus et al. 1999; Aschengrau et 

al. 1993). 

Bove et al. (2002) concluded that the 

current reproductive and developmental 

epidemiological database for exposure 

to chlorinated byproducts in drinking 

water presents moderate evidence for 

associations between DBP exposure and 

SGA, neural tube defects and 

spontaneous abortion. The authors 

acknowledged the difficulties in 

assessing exposure with any precision 

in the studies reviewed, but held the 

opinion that misclassification of 

exposure would tend to underestimate 

rather than overestimate the risk. 

3. Nieuwenhuijsen et al. 2000 

Nieuwenhuijsen et al. (2000) 

reviewed the toxicological and 

epidemiological literature and evaluated 

the potential risk of chlorination DBPs 

on human reproductive health. The 

authors state that ‘‘some studies have 

shown associations for DBPs and other 

outcomes such as spontaneous 

abortions, stillbirths and birth defects, 

and although the evidence for these 

associations is weaker it is gaining 

weight.’’ Nieuwenhuijsen et al. also 

concluded that, ‘‘although studies report 

small risks that are difficult to interpret, 

the large number of people exposed to 

chlorinated water supplies constitutes a 

public health concern.’’

4. Additional Epidemiology Studies 

Three new reproductive and 

developmental epidemiological studies 

were completed that were not included 

in the Reif et al. 2000, Bove et al. 2002, 

or Nieuwenhuijsen et al. 2000 literature 

reviews. 

Waller et al. 2001, recalculated the 

total trihalomethane exposures from 

their original publication (Waller et al.

1998) to evaluate two exposure 

assessment methods (closest site and 

utility-wide average). The new 

calculations were intended to reduce 

exposure misclassification by 

employing weighting factors and subset 

analyses. As in the 1998 publication, the 

new methods found a relationship 

between spontaneous abortion and THM 

exposure, although the unweighted 

utility-wide point estimate was lower 

than reported in the original 

manuscript. 

Hwang et al. 2002, assessed the effect 

of water chlorination byproducts on 

specific birth defects in Norway by

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49559

classifying exposure on the basis of 

chlorination (yes/no) and amount of 

natural organic matter in the water. 

Statistically significant associations 

with exposure were found for risks of 

any birth defect, cardiac, respiratory, 

and urinary tract defects. For specific 

birth defects, a statistically significant 

association was found for a defect of the 

septum in the heart. 

Windham et al., 2003, assessed the 

relationship between exposure to THMs 

in drinking water and characteristics of 

the menstrual cycle among 403 women 

who provided daily urine samples for 

an average of 5.6 cycles. Women whose 

tap water had TTHM levels more than 

0.060 mg/l had statistically significantly 

shorter menstrual cycles than women 

whose tap water had lower TTHMs. On 

average, the menstrual cycles of women 

with the higher levels of TTHMs were 

one day shorter than cycles of women 

with the lower levels (adjusted 

difference: ¥1.1 days, 95% confidence 

interval: ¥1.8 days to ¥0.4 days). This 

shortening occurred during the first half 

of the cycle, before ovulation (adjusted 

difference: ¥0.9 days; 95% confidence 

interval: ¥1.6 days to ¥0.2 days). There 

were no changes in bleed length or in 

the regularity of the cycles. Based on 

their study, Windham et al., 2003, 

suggested that THM exposure may affect 

ovarian function, but since this is the 

first study to examine human menstrual 

cycle variation in relation to THM 

exposure, more research is needed to 

confirm the relationship. The public 

health implication of a small reduction 

in menstrual cycle length is not clear, 

but if THMs are related to disturbances 

in ovarian function, that might provide 

insight into the observed associations 

between THMs and a variety of adverse 

reproductive outcomes. 

EPA’s epidemiology research program 

continues to examine the relationship 

between exposure to DBPs and adverse 

developmental and reproductive effects. 

The Agency is supporting several 

studies using improved study designs to 

provide better information for 

characterizing potential risks. Details on 

EPA’s epidemiology research program 

can be found at http://

cfint.rtpnc.epa.gov/dwportal/cfm/

dwMDBP.cfm.

B. Reproductive and Developmental 

Toxicology 

Several new reproductive and 

developmental toxicology studies have 

become available since the December 

1998 Stage 1 DBPR. This discussion 

presents some conclusions derived from 

these studies and reports, including 

hazard identification, as well as 

implications for the Stage 2 DBPR. 

EPA conducted a literature search of 

animal toxicology studies on chronic 

and subchronic DBP exposures 

associated with reproductive and 

developmental health effects, evaluated 

the current reproductive and 

developmental toxicological database 

for several individual DBPs, and 

assessed two independent reviews (Tyl 

2000 and WHO 2000). As a result of 

these analyses, EPA has concluded that 

although the database is not strong 

enough to quantify risk, it is sufficient 

to support a hazard concern. This 

hazard concern supports the need to 

address potential reproductive and 

developmental health effects in the 

Stage 2 DBPR. The following section 

describes how this conclusion was 

reached. 

1. EPA Analysis and Research 

Since the Stage 1 DBPR, EPA has 

continued to support reproductive and 

developmental toxicological research on 

various disinfection byproducts through 

extramural and intramural research 

programs. Information on EPA’s 

toxicology programs can be found at 

http://www.epa.gov/nheerl/. These 

studies, along with data on several DBPs 

published after the 1998 Stage 1 DBPR, 

are summarized in the updated 

children’s health document, ‘‘Health 

Risks to Fetuses, Infants, and Children: 

A Review’’ (USEPA 2003a). 

In addition to this compilation of 

data, EPA has also prepared individual 

health criteria documents that provide 

detailed summaries of the relevant new 

information, as well as an overall 

characterization of the human health 

risks from exposure to certain DBPs 

(USEPA 2003b-USEPA 2003h, USEPA 

2003l). From these new evaluations, 

EPA has concluded that several new 

studies on individual byproducts 

contribute to the weight of evidence for 

an association between DBP exposure 

and adverse effects on the developing 

fetus and reproduction. These effects 

include fetal loss, cardiovascular effects, 

and male reproductive effects and are 

associated with bromodichloromethane 

(BDCM), dichloroacetic acid (DCAA), 

trichloroacetic acid (TCAA), 

bromochloroacetic acid (BCAA), and 

dibromoacetic acid (DBAA). The data 

from these new studies do not change 

the MCLGs that were established as a 

part of the Stage 1 DBPR. 

2. Tyl 2000 

Tyl (2000) conducted a 

comprehensive review of the 

reproductive and developmental 

toxicology literature on DBPs 

representing over thirty-five studies. 

Adverse effects reported by these 

studies include developmental effects, 

whole litter resorption, reduced fetal 

body weights, and male reproductive 

effects (e.g., inhibited spermiation, 

increased abnormal sperm). Many of 

these studies are categorized as highdose, short-term screening studies that 

can be used to assess potential hazard 

(Table III–1), while the long term, twogeneration reproduction studies could 

be an appropriate basis for quantitative 

risk assessment.

Disinfectant/DBP Screening 1 Developmental 2 Two-generation 3

reproductive 

Chlorine ............................................................................................................................. ........................ ✔

Chlorine Dioxide ................................................................................................................ ✔ ✔

Chloramine ........................................................................................................................ ........................ ✔

Chloroform ......................................................................................................................... ✔ ✔✔

Bromoform ......................................................................................................................... ✔ ✔✔

Bromodichloromethane ..................................................................................................... ✔ ✔ in progress 

Dibromochloromethane ..................................................................................................... ✔ ✔

Monochloroacetic acid ....................................................................................................... ✔ ✔

Dichloroacetic acid ............................................................................................................ ✔ ✔

Trichloroacetic acid ........................................................................................................... ✔ ✔

Monobromoacetic acid ...................................................................................................... ✔ ✔

Dibromoacetic acid ............................................................................................................ ✔ ✔ in progress 

Tribromoacetic acid ........................................................................................................... ✔ ..........................

Bromochloroacetic acid ..................................................................................................... ✔ .......................... in planning stage 

Bromodichloroacetic acid .................................................................................................. ✔ ..........................

Dibromochloroacetic acid .................................................................................................. ✔ ..........................

49560 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

Disinfectant/DBP Screening 1 Developmental 2 Two-generation 3

reproductive 

Chloroacetonitrile ............................................................................................................... ✔ ..........................

Dichloroacetonitrile ............................................................................................................ ✔ ✔

Trichloroacetonitrile ........................................................................................................... ✔ ✔

Bromoacetonitrile ............................................................................................................... ✔ ✔

Dibromoacetonitrile ............................................................................................................ ✔ ..........................

Tribromoacetonitrile ........................................................................................................... ........................ ..........................

Bromochloroacetonitrile ..................................................................................................... ✔ ✔

Propanal ............................................................................................................................ ✔ ✔

1,1 Dichloropropanone ...................................................................................................... ✔ ..........................

Hexachloropropanone ....................................................................................................... ✔ ..........................

Dichloromethane ............................................................................................................... ✔ ..........................

MX ..................................................................................................................................... ✔ ✔

Bromate ............................................................................................................................. ✔ ..........................

Chlorite .............................................................................................................................. ✔ ✔✔

✔ denotes the availability of at least one study in the following categories. 1Screening studies are for hazard identification. These types of studies include the following: whole embryo culture, NTP 35-day screening 

studies, Chernoff-Kavlock and its modified version, and short-term male reproductive toxicity screen. 2 Developmental studies are used for dose-response determinations. 

3Two-generation reproductive studies are multi-generation reproductive toxicity studies used for dose-response determinations. 

Tyl concluded that, ‘‘The screening 

studies, performed for a number of 

DBPs, are ‘adequate’ and ‘sufficient’

only to detect potent reproductive/

developmental toxicants for hazard 

identification.’’ Tyl further confirms 

that the database identifies certain DBPs 

with potential reproductive or 

developmental effects (Table III–2) and 

these are discussed further in the next 

section.

TABLE III–2.—POTENTIAL HAZARDS OF DBPS FOR REPRODUCTIVE AND DEVELOPMENTAL EFFECTS (ADAPTED FROM TYL, 

2000) 

Type of hazard Disinfection byproducts 

Developmental defects ............................................................................. TCAA, DCAA, MCAA and chlorite. 

Whole litter resorption .............................................................................. Chloroform, bromoform, BDCM, DBCM, DCAA, TCAA, DCAN, and 

TCAN. 

Fetotoxicity (reduced fetal body weights, increased variations) .............. Chloroform, BDCM, DBCM, DCAA, TCAA, DCAN, TCAN, DBAN, 

BCAN, MCAN. 

Male reproductive effects (spermatotoxic) ............................................... DCAA, DBAA, BDCM. 

a. Developmental defects. Tyl noted 

that adverse developmental effects that 

were reported from whole embryo 

culture tests on the developing heart, 

neural tube, eye, pharyngeal arch, and 

somites tended to be associated with 

haloacetic acids tested at high doses 

(Hunter et al. 1996; Saillenfait et al.

1995, Smith et al. 1989). Cardiovascular 

effects were also observed in vivo for 

TCAA and DCAA from developmental 

segment II toxicity studies at high doses 

(Smith et al. 1988, 1990). 

b. Whole litter resorption. Whole litter 

resorption, likened to miscarriage or 

spontaneous abortion by Tyl 2000, was 

also observed at high doses in vivo for 

a range of DBPs as indicated in Table 

III–2 (Murray et al. 1979, Balster and 

Borzellca, 1982, Narotsky et al. 1992; 

1997 a, b; Bielmeier et al. 2001; Smith 

et al. 1990; Smith et al. 1988). Tyl noted 

that similar effects were observed in 

several epidemiology studies. 

c. Fetal toxicity. Fetal toxic effects 

such as reduced fetal body weights and 

increased variation were observed at 

high doses in vivo for a range of DBPs 

(e.g., chloroform, BDCM, DBCM, DCAA, 

TCAA, DCAN, TCAN, DBAN, BCAN) 

(Thompson et al. 1974; Schwetz et al.

1974; Murray et al. 1979; Ruddick et al.

1983; Narotsky et al. 1992, Balster and 

Borzelleca, 1982; Smith et al. 1990). 

Again, Tyl noted a similarity in effects 

observed in epidemiology studies. 

d. Male reproductive effects. Animal 

toxicology studies report increased risks 

of adverse effects on the male 

reproductive system from high doses of 

haloacetic acids and other DBPs that 

have not been studied in human 

epidemiology studies. Male 

reproductive effects (e.g., inhibited 

spermiation, reduced epididymus, 

sperm number and motility, increased 

abnormal sperm, testicular damage and 

inhibited in vitro fertilization) were 

reported for DCAA, DBAA, TCAA and 

BDCM (Toth et al. 1992, Linder et al.

1997a, b; Linder et al. 1994a, b; Cosby 

and Dukelow 1992). Dr. Tyl noted that 

the adverse effects observed in the male 

reproductive toxicity screening studies 

(Toth et al. 1992; Linder et al. 1994a, b; 

1997a, b) are confounded by a short 

dosing regimen and administration of 

test doses to only adult males. 

From her review of the 

comprehensive animal toxicology 

database on reproductive and 

developmental health effects from DBP 

exposure, Dr. Tyl concludes that ‘‘some 

DBPs have an intrinsic capacity to do 

harm, specifically to the developing 

conceptus and the male (and possibly 

the female) reproductive system’’. She 

concludes that ‘‘there is hazard to 

development from the haloacetic acids 

(TCAA, DCAA, MCAA) and acetate; to 

development from chloroform, 

bromoform, BDCM, DBCM, DCAA, 

TCAA, DCAN, and TCAN expressed as 

full litter resorption (which most likely 

indicates maternal endocrine/uterine 

effects); and fetotoxicity for chloroform, 

BDCM, DBCM, DCAA, TCAA, DCAN, 

TCAN, DBAN, BCAN, CAN, 

acetaldehyde, and possibly 

formaldehyde. Reproductive hazard 

exists for DCAA, DBAA, and possibly 

formaldehyde in males and for TCE and 

possibly formaldehyde in females.’’

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49561

3. World Health Organization Review of 

the Reproductive and Developmental 

Toxicology Literature (2000) 

The International Programme on 

Chemical Safety (IPCS) published an 

evaluation of Disinfectants and DBPs in 

its Environmental Health Criteria

monograph series (WHO 2000). In this 

review of the toxicology data on 

reproductive and developmental effects 

from DBP exposure, the World Health 

Organization (WHO) concludes that 

although the data on these effects are 

not as robust as the cancer database, 

these effects are of potential health 

concern. The WHO concludes that 

reproductive effects in females have 

been principally embryolethality and 

fetal resorptions associated with the 

haloacetonitriles (trichloroacetonitrile, 

dichloroacetonitrile, 

bromochloroacetonitrile, and 

dibromoacetonitrile) and the 

dihaloacetates, while DCAA and DBAA 

have both been associated with adverse 

effects on male reproduction. 

4. New Studies 

Christian et al. (2001) conducted a 

developmental toxicity study with 

pregnant New Zealand White rabbits 

exposed to BDCM in drinking water at 

concentrations of 0, 15, 150, 450, and 

900 ppm in drinking water on gestation 

days 6–29. The no observed adverse 

effect level (NOAEL) and lowest 

observed adverse effect level (LOAEL) 

identified for maternal toxicity in this 

study were 13.4 mg/kg-day (150 ppm) 

and 35.6 mg/kg-day (450 ppm), 

respectively, based on decreased body 

weight gain. The developmental NOAEL 

was 55.3 mg/kg-day (900 ppm) based on 

absence of statistically significant, doserelated effects at any tested 

concentration. Christian et al. (2001) 

also conducted a developmental study 

of BDCM in a second species, SpragueDawley rats. Rats were exposed to 

BDCM in the drinking water at 

concentrations of 0, 50, 150, 450, and 

900 ppm on gestation days 6 to 21. The 

concentration-based maternal NOAEL 

and LOAEL for this study were 150 ppm 

and 450 ppm, respectively, based on 

statistically significant, persistent 

reductions in maternal body weight and 

body weight gains. Based on the mean 

consumed dosage of 

bromodichloromethane, these 

concentrations correspond to doses of 

18.4 mg/kg-day and 45.0 mg/kg-day, 

respectively. The concentration-based 

developmental NOAEL and LOAEL 

were 450 ppm and 900 ppm, 

respectively, based on a significantly 

decreased number of ossification sites 

per fetus for the forelimb phalanges 

(bones of the hand or the foot) and the 

hindlimb metatarsals and phalanges. 

These concentrations correspond to 

mean consumed doses of 45.0 mg/kgday and 82.0 mg/kg-day, respectively. 

Christian et al. (2002b) summarized 

the results of a two-generation 

reproductive toxicity study on 

bromodichloromethane conducted in 

Sprague-Dawley rats. 

Bromodichloromethane was 

continuously provided to test animals in 

the drinking water at concentrations of 

0, 50, 150, or 450 ppm. Average daily 

doses estimated for the 50, 150, and 450 

ppm concentrations were reportedly 4.1 

to 12.6, 11.6 to 40.2, and 29.5 to 109 mg/

kg-day, respectively. The parental 

NOAEL and LOAEL were 50 and 150 

ppm, respectively, based on statistically 

significant reduced body weight and 

body weight gain; F1 and F2 generation 

pup body weights were reduced in the 

150 and 450 ppm groups during the 

lactation period after the pups began to 

drink the water provided to the dams. 

Body weight and body weight gain were 

also reduced in the 150 and 450 ppm F1 

generation males and females. A 

marginal effect on estrous cyclicity was 

observed in F1 females in the 450 ppm 

exposure group. Small (≤6%), but 

statistically significant, delays in F1 

generation sexual maturation occurred 

at 150 (males) and 450 ppm (males and 

females) as determined by timing of 

vaginal patency or preputial separation. 

The study’s authors considered these 

effects to be a secondary response 

associated with reduced body weight, 

which appears to be dehydration 

brought about by taste aversion to the 

compound. The results of this study 

identify NOAEL and LOAEL values for 

reproductive effects of 50 ppm (4.1 to 

12.6 mg/kg-day) and 150 ppm (11.6 to 

40.2 mg/kg-day), respectively, based on 

delayed sexual maturation.

Bielmeier et al. (2001) conducted a 

series of experiments to investigate the 

mode of action in 

bromodichloromethane-induced full 

litter resorption (FLR). The study 

included a strain comparison of F344 

and Sprague-Dawley (SD) rats. In the 

strain comparison experiment, female 

SD rats (13 to 14/dose group) were 

dosed with 0, 75, or 100 mg/kg-day by 

aqueous gavage in 10% Emulphor on 

GD 6 to 10. F344 rats (12 to 14/dose 

group) were dosed with 0 or 75 mg/kgday administered in the same vehicle. 

The incidence of FLR in the 

bromodichloromethane-treated F344 

rats was 62%, while the incidence of 

FLR in SD rats treated with 75 or 100 

mg/kg-day of bromodichloromethane 

was 0%. Both strains of rats showed 

similar signs of maternal toxicity, and 

the percent body weight loss after the 

first day of dosing was comparable for 

SD rats and the F344 rats that resorbed 

their litters. The rats were allowed to 

deliver and pups were examined on 

postnatal days 1 and 6. Surviving litters 

appeared normal and no effect on postnatal survival, litter size, or pup weight 

was observed. The series of experiments 

conducted by Bielmeier et al. (2001) 

identified a LOAEL of 75 mg/kg-day (the 

lowest dose tested) based on FLR in 

F344 rats. A NOAEL was not identified. 

Mechanistic studies indicate that 

BDCM-induced pregnancy loss is likely 

to be luteinizing hormone (LH)-

mediated (Bielmeier et al., 2001). It is 

possible that BDCM alters LH levels by 

disrupting the hypothalamic-pituitarygonadal axis or by altering the 

responsiveness of the corpora lutea to 

LH. Since these possible mechanisms 

are potentially relevant to pregnancy 

maintenance in humans, EPA believes 

the finding of BDCM-induced pregnancy 

loss in F344 rats is relevant to risk 

assessment, and may provide insight 

into the epidemiological finding of 

increased risk of spontaneous abortion 

associated with consumption of BDCM 

(Waller et al. 1998, 2001). 

Christian et al. (2002a) recently 

completed a two-generation drinking 

water study of DBA in rats. Male and 

female Sprague-Dawley rats (30/sex/

exposure group) were administered 

DBA in drinking water at concentrations 

of 0, 50, 250, or 650 ppm continuously 

from initiation of exposure of the 

parental (P) generation male and female 

rats through weaning of the F2 offspring. 

Based on testicular histomorphology 

indicative of abnormal spermatogenesis 

in P and F1 males, the parental and 

reproductive/developmental toxicity 

LOAEL and NOAEL are 250 and 50 

ppm, respectively. 

Previous studies by EPA have 

reported adverse effects of DBA, 

administered via oral gavage, on 

spermatogenesis that impacted male 

fertility (Linder et al. 1994a, 1995, 

1997a) at doses-comparable to those 

achieved in the Christian et al. (2002a) 

study. Based on these studies 

collectively, it is clear that DBA is 

spermatotoxic. Moreover, 

Veeramachaneni et al. (2000) reported 

in an abstract that sperm from male 

rabbits exposed to DBA in utero from 

gestation days 15 and throughout life 

reduced the fertility of artificially 

inseminated females as evidenced by 

reduced conceptions. When published, 

this study may support the evidence 

that DBA is a male reproductive system 

toxicant . 

In addition, research on DBA by 

Klinefelter et al. (2001) has

49562 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

demonstrated statistically significant 

delays in both vaginal opening and 

preputial separation using the body 

weight on the day of acquisition 

(postnatal day 45) as the co-variant. This 

was not found by Christian et al (2002a) 

using the body weight at weaning as the 

statistical covariant. However, the 

authors analyzed the data for preputial 

separation and vaginal opening with 

body weight on the day of weaning as 

a co-variant rather than body weight on 

the day of acquisition, i.e., the day that 

the prepuce separates or the day the 

vagina opens. It is likely that there was 

an increase in body weight from 

postnatal day 21 (weaning) until 

preputial separation (day 45) that was 

independent of the delay in sexual 

maturation. 

Although the Christian et al. (2002a) 

study was conducted in accordance 

with EPA’s 1998 testing guidelines, EPA 

has incorporated newer, more 

sophisticated measures into recent 

intramural and extramural studies that 

have not yet been incorporated into the 

testing guidelines. Such measures 

include measuring changes in specific 

proteins in the sperm membrane 

proteome and fertility assessments via 

in utero insemination. EPA believes that 

additional research is needed, utilizing 

these newer toxicological measures, to 

clarify the extent to which DBA poses 

human reproductive or developmental 

risk. The database on male reproductive 

effects from exposure to DBA is 

incomplete and is not suitable for 

quantitative risk assessment at this time. 

It does, however, identify reproductive 

effects as an area of concern. 

C. Conclusions Drawn From the 

Reproductive and Developmental 

Health Effects Data 

EPA believes that the weight of 

evidence of the best available science, in 

conjunction with the widespread 

exposure, supports regulatory changes 

that target peak DBP exposures 

specifically through the Stage 2 DBPR. 

Several epidemiology studies found 

statistically significant associations 

between exposure to chlorinated 

drinking water and fetal growth, 

spontaneous abortion, stillbirth, and 

neural tube defects. Although 

uncertainties remain and the current 

database does not support a quantitative 

reproductive and developmental risk 

assessment for most of the DBPs, the 

weight of evidence provides an 

indication of a hazard concern that 

warrants additional regulatory action 

beyond the Stage 1 DBPR. 

Biological plausibility for the effects 

observed in epidemiological studies has 

been demonstrated through various 

toxicological studies. Tyl 2000 states 

that ‘‘effects observed in animal studies 

included embryonic heart and neural 

tube defects from haloacetic acids in 

vitro and in vivo, and full litter 

resorption, reduced numbers of 

implants per litter, and reduced fetal 

body weight per litter were also 

observed from exposure to specific 

trihalomethanes. Comparable effects 

were also observed in children in some 

(but not all) epidemiological studies, 

with exposure to trihalomethanes 

(THMs) usually used as a surrogate for 

specific DBP classes or individual DBPs, 

as follows: increased incidences of 

cardiac defects (Bove et al. 1995) and of 

neural tube defects in children (Bove et 

al. 1995; Dodds et al. 1999; Klotz and 

Pyrch 1998) were reported. Intrauterine 

growth retardation (IUGR, 

approximately equivalent to reduced 

fetal body weights per litter) was 

reported to be associated with 

waterborne chloroform (Kramer et al.

1992; Bove et al. 1995; Gallagher et al.

1998). Miscarriage or spontaneous 

abortion, or stillbirth (approximately 

equivalent to whole litter resorption, 

reduced numbers of total and/or live 

implants per litter, and increased 

resorptions per litter) were observed by 

Waller et al., 1998; Dodds et al., 1999; 

and Bove et al., 1995.’’

Similarity of effects between animals 

and humans lends credence to and 

strengthens the weight of evidence for 

an association between adverse 

reproductive and developmental health 

effects and exposure to chlorinated 

surface water. EPA believes that the 

weight of evidence of both the 

reproductive and developmental 

toxicological and epidemiological 

databases suggests that exposure to 

DBPs may induce potential adverse 

health effects on reproduction and fetal 

development at some DBP exposures. 

However, additional toxicological work 

is necessary to identify the mode of 

action for the effects observed. 

D. Cancer Epidemiology 

Epidemiological studies on cancer 

provide valuable information that 

contributes to the overall evidence on 

the potential human health hazards 

from exposure to chlorinated drinking 

water. In the area of epidemiology, a 

number of studies have been conducted 

to investigate the relationship between 

exposure to chlorinated surface water 

and cancer. While EPA cannot conclude 

there is a causal link between exposure 

to chlorinated surface water and cancer, 

some studies have found an association 

between bladder, rectal and colon 

cancer and exposure to chlorinated 

surface water. 

1. Population Attributable Risk Analysis 

Some epidemiological studies have 

linked the consumption of chlorinated 

surface waters to an increased risk of 

two major causes of human mortality in 

the United States, colorectal and 

bladder cancers (Cantor 1998). Bladder 

cancer was chosen as the primary 

endpoint of concern in the Stage 1 

DBPR (USEPA 1998f) economic analysis 

because it had the most consistent 

database for a possible association to 

chlorinated surface water exposure. 

More studies have considered bladder 

cancer than any other cancer. EPA used 

the published mean risk estimates from 

five studies to quantify the potential 

range of risk for bladder cancer from 

DBP exposure. These risks were 

expressed as a range of population 

attributable risks (PAR) of 2–17% 

(USEPA 1998f). This means that if the 

associations reported in the studies turn 

out to reflect a causal link, between 2 

and 17% of new bladder cancer cases 

could be attributable to DBPs. This PAR 

range also represents that portion of the 

bladder cancer cases that would not 

have occurred if the exposure to 

chlorinated drinking water were absent. 

A complete discussion of the Stage 1 

DBPR bladder cancer PAR evaluation, 

including uncertainties and 

assumptions, can be found in the Stage 

2 DBPR Economic Analysis (USEPA 

2003i). 

While EPA recognized the limitations 

of the epidemiological database for 

making risk estimates, the Agency 

believed that it was useful for 

developing an estimate of bladder 

cancer risk. The PARs were derived 

from measured risks (Odds Ratios and 

Relative Risk) based on the number of 

years exposed to chlorinated surface 

water. The uncertainties associated with 

these PAR estimates are largely due to 

the common prevalence of both the 

disease (bladder cancer) and exposure 

(chlorinated drinking water). EPA 

recognizes that risks from chlorinated 

drinking water may be lower or higher 

than those estimated from the 

epidemiological literature, and that the 

PAR range could include zero or be 

higher than 17%. 

Using the PARs of 2% and 17%, EPA 

estimated that the number of possible 

bladder cancer cases per year 

potentially associated with exposures to 

DBPs in chlorinated drinking water 

could range from 1,100 to 9,300 cases. 

This was based on the estimate of 

54,500 new bladder cancer cases per 

year nationally, as projected by the 

National Cancer Institute for 1997. A 

thorough discussion of cancer studies 

published prior to 1998 and possible

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49563

associations with DBP exposure can be 

found in the Stage 1 DBPR (USEPA 

1998c). 

2. New Epidemiological Cancer Studies

New studies published since the Stage 

1 DBPR continue to support an 

association between bladder, colon and 

rectal cancers and exposure to 

chlorinated surface water (Yang et al.

1998; Koivusalo et al. 1998; King et al.

2000b). Based on the weight of evidence 

provided by the cancer epidemiology 

database, EPA has chosen to use the 

same PAR analysis to estimate the 

primary benefits from bladder cancer 

cases potentially avoided as a 

consequence of reducing the DBP levels 

from the Stage 2 DBPR (see section VII). 

For the Stage 2 DBPR analysis, EPA 

updated the 1997 estimate of new 

bladder cancer cases per year nationally 

from 54,500 to 56,500 (projected by the 

American Cancer Society, 2002) and 

accounted for the reductions in DBP 

exposure that were projected for the 

Stage 1 DBPR. 

a. New bladder cancer studies.

Bladder cancer and chlorinated DBP 

exposure has historically been the most 

strongly supported association of all the 

possible cancers, based on human 

evidence. Two new studies (Yang et al.

1998 and Koivusalo et al. 1998) also 

suggest an association of DBP exposure 

with bladder cancer. Yang et al. 1998 

found a positive association between 

consumption of chlorinated drinking 

water and bladder cancer. Koivusalo et 

al. (1998) found evidence of increased 

risk as a function of increasing DBP 

exposure duration. Long exposure 

durations (≥45 years for Koivusalo et al.

1998) were associated with about a twofold increase in risk. The new bladder 

cancer studies continue to support an 

association and potential for a causal 

relationship between exposure to 

chlorination byproducts and risk for 

bladder cancer. 

A new publication by C.M. Villanueva 

et al. (Villanueva et al. 2003) reports on 

their meta-analysis of case-control and 

cohort studies. This meta-analysis may 

be useful for improving the estimate of 

national population attributable risk 

(fraction of bladder cancer cases in the 

U.S. that may be attributed to 

chlorinated drinking water). Compared 

to EPA’s current approach (i.e., 

providing a range of population 

attributable risks (PAR)), use of the 

meta-estimate would provide a more 

stable result because: 

• It provides a single (meta) estimate 

of the odds ratio from which to calculate 

the PAR, thereby summarizing the 

results across studies, thus reducing the 

influence of geographic and temporal 

differences. 

• It uses three additional high-quality 

studies not included in the PAR range 

analysis conducted by EPA (i.e., studies 

by Koivusalo et al. 1998, Doyle et al.

1997, and Vena et al. 1993). 

• It weights the individual studies 

according to their precision, so more 

precise estimates (due principally to 

greater numbers of cases) carry greater 

statistical weight and therefore have 

greater influence on the meta-estimate. 

• In addition to the primary analysis, 

the authors conducted an evaluation of 

the robustness of their conclusions. 

They examined the sensitivity of 

estimates to decisions made with 

respect to exposure definitions, cut 

points defining exposure groups, 

inclusion/exclusion of individual 

studies, and potential publication bias. 

The meta-analysis provided at least 

two meta-estimates that may be useful 

for estimating national population 

attributable risk: 

• A combined odds ratio for everexposure, with confidence intervals and 

• A combined dose-response 

regression slope coefficient, relating 

increasing odds ratios to additional 

years of chlorinated drinking water 

consumption. 

EPA conducted an estimate of the 

impact of using the meta-analysis to 

provide a perspective on the national 

population attributable risk. This 

estimate is based on the author’s 

correction of a minor transcription error 

in their published manuscript (the 

appropriate estimate for the King study 

yields corrected over-all odds ratio for 

ever-consumers of 1.2 with 95% 

confidence interval of 1.091 to 1.320, 

personal communication from M. 

Kogevinas to M. Messner, 5/19/2003). 

Assuming 70% of the U.S. population is 

in the ever-consumed category (based 

on the chlorinated surface water 

exposed population), a point estimate of 

the population attributable risk using 

the odds ratio from the meta-analysis is 

12% (95% interval 6% to 18%). 

Although EPA’s population attributable 

risk range (2% to 17%) was not 

intended to convey a quantified level of 

confidence, it is not vastly different 

from the meta-analysis’ 95% confidence 

range of 6% to 18%. EPA regards the 

meta-range as additional support for 

EPA’s population attributable risk range. 

The meta-analysis provides continued 

support for an association between 

exposure to chlorinated surface water 

and bladder cancer. 

EPA requests comment on the use of 

a meta-estimated odds ratios to estimate 

national population attributable risk for 

the purpose of supporting the benefit 

analysis for this rule, either based 

specifically on the Villanueva et al.

publication or on the application of a 

similar approach. EPA also solicits 

comments and suggestions for use of the 

combined dose-response regression 

slope coefficient associated with the 

increased risk of bladder cancer for each 

additional year’s exposure to DBPs in 

drinking water for estimating the drop 

in risk associated with a reduction in 

DBPs as part of the benefit analysis of 

this rule. EPA provides further 

discussion and solicitation of comment 

on how the slope factor might further be 

considered in estimating the benefits of 

this rule in the economic section of this 

preamble. 

b. New colon cancer studies.

Colorectal cancer is the third most 

common type of new cancer cases and 

deaths in both men and women in the 

U.S. It is estimated that 148,300 new 

colorectal cancer cases will be 

diagnosed in 2002, with 56,600 

resulting in deaths (American Cancer 

Society, 2002). Human epidemiology 

studies on chlorinated surface water 

have reported associations with 

colorectal cancer. Since the Stage 1 

DBPR, two new human epidemiology 

studies (Yang et al. 1998 and King et al.

2000b) have been conducted to 

investigate the relationship between 

colon cancer and exposure to 

chlorinated surface water. Yang et al.

1998 did not identify an association 

between consumption of chlorinated 

drinking water and colon cancer. The 

King et al. (2000b) study found evidence 

of a DBP association with colon cancer 

among males, but no association was 

observed among females. 

Similarity of effects reported in 

animal toxicity and human 

epidemiology studies strengthen the 

weight of evidence for an association 

between DBP exposure and colon 

cancer. Effects observed in animal 

studies which included tumors in 

BDCM exposed rats and mice at several 

sites (NTP 1987); colon tumors in 

bromoform exposed rats (NTP 1989); 

and development of aberrant crypt foci, 

a preneoplastic lesion of colon cancer in 

animals exposed to DBP mixtures 

(DeAngelo et al. 2002), are comparable 

to observations in some cancer 

epidemiological studies showing an 

association with colorectal cancer and 

consumption of chlorinated water (King 

et al. 2000b). 

Even with the additional study 

showing an association, the 

epidemiological database on colon 

cancer as a whole is not as strong as that 

for bladder cancer. However, this new 

study increases the weight of evidence 

of an association between DBP exposure

49564 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

and colon cancer. The Stage 1 DBPR 

(USEPA 1998c) includes additional 

discussion of colon cancer risks 

associated with DBP exposure. 

c. New rectal cancer studies. The 

evidence for an association between 

DBPs and rectal cancer is stronger than 

for colon cancer. Yang et al. (1998) and 

Hildesheim et al. (1998) both found 

associations between chlorinated 

drinking water exposure and rectal 

cancer, and the associations had a 

similar magnitude in both sexes. 

Hildesheim et al. also found an 

association in both sexes with lifetime 

average THM concentration. The 

consistency of the dose-response trends, 

the consistency between sexes, and the 

apparent control of important potential 

confounders in this study all support 

the observed associations. 

d. Other cancers. Two new human 

epidemiology studies support the 

possibility of an association between 

DBPs and kidney cancer. Yang et al.

(1998) found a positive association for 

both males and females between 

consumption of chlorinated drinking 

water and kidney cancer. Koivusalo et 

al. (1998) found a small, statistically 

significant, exposure-related excess risk 

for kidney cancer for males. The 

association for females was not 

significant in the Koivusalo et al. 1998 

study. The current database for this 

endpoint of cancer, however, is 

insufficient to conclude an association. 

Cantor et al. (1999) studied brain 

cancer, focusing on gliomas. None of the 

exposure variables were related to brain 

cancer among females, but males 

showed a statistically significant, 

monotonically increasing risk associated 

with duration of exposure to chlorinated 

surface water. This study suggests a 

possible association between 

chlorination byproducts and gliomas; 

however, the evidence from this study 

is not strong enough to support a 

conclusion of a causal association. 

Infante-Rivard et al. (2001) conducted 

a population-based case-control study in 

Quebec Province, Canada, to examine 

possible associations between 

childhood acute lymphoblastic 

leukemia and THMs. There were no 

associations with leukemia for any of 

the exposure indices for total THM, or 

specific THMs. Therefore, the study 

does not provide evidence of an 

association between any of the exposure 

variables and childhood leukemia. 

3. Review of the Cancer Epidemiology 

Literature (WHO 2000) 

The International Programme on 

Chemical Safety (IPCS) report on 

disinfectants and disinfection 

byproducts (WHO 2000) concludes that 

results of analytical epidemiological 

cancer studies are insufficient to 

support a causal relationship for 

bladder, colon, rectal, or any other 

cancer and chlorinated drinking water 

or THMs. The report notes that there is 

better evidence for an association 

between exposure to chlorinated surface 

water and bladder cancer than for other 

types of cancer. The WHO also 

concludes that based on the large 

number of people exposed to 

chlorinated drinking water, there is a 

need to address this potential health 

concern. 

E. Cancer and Other Toxicology 

Few new cancer toxicology studies 

have been completed since the Stage 1 

DBPR was finalized in December 1998. 

The information provided in the 

following sections adds to the 

toxicology database and provides 

additional support for the Stage 2 DBPR 

to control DBP peaks (e.g, high TTHM 

and HAA5 levels) throughout 

distribution systems, but does not 

change the quantitative assessment of 

the MCLGs. 

1. EPA Criteria Documents 

To date, EPA has established lifetime 

cancer risk levels for four DBPs 

(bromoform, bromodichloromethane, 

bromate, and dichloroacetic acid) 

classified as ‘‘probable’’ carcinogens, as 

promulgated in the Stage 1 DBPR and 

reported in the Integrated Risk 

Information System (IRIS). Although 

researchers have continued to assess the 

cancer risks of DBPs, there has been 

little change in the overall DBP 

carcinogenicity database since the Stage 

1 DBPR.

The most significant new publication 

since the Stage 1 DBPR was a study of 

DCAA tumorigenicity in mice by 

DeAngelo et al. (1999). The Agency has 

used the data from this study to revise 

the slope factor for DCAA and a 

drinking water 10¥6 lifetime cancer risk 

concentration. The slope factor is a 

measure of the potency of a carcinogen 

while the 10¥6 lifetime cancer risk 

concentration provides an estimate of 

the concentration of a contaminant in 

drinking water that is associated with an 

estimated excess lifetime cancer risk of 

one in a million (Table III–3). 

Another significant advancement 

beyond the Stage 1 DBPR was the 

evaluation of the chloroform 

tumorigenicity data on the basis of its 

nonlinear mode of action following the 

draft 1999 proposed Guidelines for 

Carcinogen Risk Assessment (USEPA 

1999a). The new chloroform assessment 

became available on IRIS (2001) in 

October, 2001 (see section V for a more 

detailed discussion). 

The Criteria Documents for 

bromoform, bromodichloromethane, 

dibromochloromethane, and 

dichloroacetic acid that support the 

Stage 2 proposal include cancer slope 

factors and 10¥6 lifetime cancer risk 

concentrations that have been modified 

from their Stage 1 values in order to 

reflect the methodology proposed in the 

1996/1999 draft cancer guidelines 

(USEPA 1999a) (Table III–3). These 

include the values based on the 

Maximum Likelihood Estimate of the 

dose producing effects in 10 percent of 

the animals (ED10) and from the lower 

95 percent confidence bound on that 

value (LED10). Except for 

dibromochloromethane, which is 

classified as a possible human 

carcinogen, the DBPs in Table III–3 (and 

bromate as noted previously) are 

classified as probable human 

carcinogens.

TABLE III—3.—QUANTIFICATION OF CANCER RISK

Risk factors from LED10 Risk factors from ED10

Disinfection byproduct Slope factor 

(mg/kg/day)¥1

10¥6 Risk

concentration 

(mg/L) 

Slope factor 

(mg/kg/day)¥1

10¥6 Risk

concentration 

(mg/L) 

Bromodichloromethane ............................................................................ 0.034 0.001 0.022 0.002

Bromoform ............................................................................................... 0.0045 0.008 0.0034 0.01

Dibromochloromethane ............................................................................ 0.04 0.0009 0.017 0.002

Dichloroacetic Acid .................................................................................. 0.048 0.0007 0.014 0.003

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49565

EPA believes that it is important to 

pursue additional research on cancer 

from DBPs. EPA has several ongoing 

studies in addition to a collaboration 

with the National Toxicology Program 

of the National Institute of 

Environmental Health Sciences. More 

information on EPA’s toxicology 

research program can be found at http:/

/www.epa.gov/nheerl.

2. Other Byproducts with Carcinogenic 

Potential 

a. 3-chloro-4-(dichloromethyl)-5-

hydroxy-2(5H)-furanone) (MX)—

multisite cancer. MX is a byproduct of 

chlorination that is typically found at 

very low concentrations (approximately 

<0.000067 mg/L) in drinking water. The 

information available on MX was 

recently compiled in the Quantitative 

Cancer Assessment for MX and 

chlorohydroxyfuranones (USEPA 

2000i). Overall, the weight of evidence 

indicates that MX is a direct-acting 

genotoxicant in mammals, with the 

ability to induce tumors in multiple 

sites. The primary sites for tumor 

formation are the thyroid and liver. 

b. N-nitrosodimethylamine (NDMA)—

multisite cancer. Health effects data 

indicate that NDMA is a probable 

human carcinogen, as described on IRIS 

(1991). Risk assessments have estimated 

that the 10¥6 lifetime cancer risk level 

is 0.000007 mg/L based on induction of 

tumors at multiple sites. Recent studies 

have produced new information on the 

occurrence and mechanism of formation 

of NDMA but there is not enough 

information at this time to draw 

conclusions. More research is underway 

to determine the mechanism by which 

NDMA is formed in drinking water, and 

the extent of its occurrence in 

chloraminated systems. 

3. Other Toxicological Effects 

The Agency has modified the 

reference dose (RfD) values for 2 of the 

chlorinated acetic acids since the Stage 

1 DBPR. Under the Stage 1 DBPR there 

was no established RfD for 

monochloroacetic acid (MCAA). Data 

from a drinking water exposure study of 

MCAA in rats by DeAngelo et al. (1997) 

were used to establish an RfD of 0.004 

mg/kg/day based on observed increases 

in spleen weight. Data from DeAngelo 

(1997) were also used to calculate a new 

RfD of 0.03 mg/kg/day for 

trichloroacetic acid (TCAA) based on 

observed effects on body weight and 

liver effects. Detailed discussions of the 

new reference doses are located in 

section V of this preamble. 

4. WHO Review of the Cancer 

Toxicology Literature (2000) 

The IPCS report on Disinfectants and 

Disinfection Byproducts (WHO 2000) 

emphasizes that the bulk of the 

toxicology data focuses primarily on 

carcinogenesis. The Task Group found 

BDCM to be of particular interest 

because it produces tumors in both rats 

and mice at several sites. Although the 

HAAs appear to be without significant 

genotoxic activity, the brominated 

HAAs appear to induce oxidative 

damage to DNA, leading to tumor 

formation. 

F. Conclusions Drawn From the Cancer 

Epidemiology and Toxicology 

EPA believes that the cancer 

epidemiology and toxicology databases 

provide important information that 

contributes to the weight of evidence 

evaluation of the potential health risks 

from exposure to chlorinated drinking 

water. At this time the cancer 

epidemiology studies are insufficient to 

establish a causal relationship between 

exposure to chlorinated drinking water 

and cancer, but EPA does believe there 

is a potential association. The current 

database is sufficient for quantitative 

analysis on the endpoint of bladder 

cancer, as presented previously in the 

PAR analysis. 

The association between DBP 

exposure and colon cancer remains 

more tenuous than the link to bladder 

cancer, although similarity of effects 

reported in animal toxicity and human 

epidemiology studies strengthens the 

weight of evidence for an association 

between DBP exposure and colon 

cancer. Studies finding potential 

relationships between exposure to 

chlorinated drinking water and rectal, 

kidney, and brain cancer also add to the 

weight of evidence for a public health 

concern. EPA believes that the overall 

cancer epidemiology and toxicology 

data support the decision to pursue 

additional DBP control measures as 

reflected in the Stage 2 DBPR. 

G. Request for Comment 

EPA requests comment on the 

conclusions drawn from the new health 

information summarized in this section. 

EPA requests comment on the weight of 

evidence evaluation of the potential 

reproductive and developmental 

hazards from DBPs and its potential 

implications for the regulatory 

provisions for the final Stage 2 DBPR. 

EPA solicits any additional data on the 

reproductive or developmental effects 

from DBPs that need to be considered 

for the final Stage 2 DBPR. 

EPA requests comment on EPA’s 

conclusions regarding cancer 

epidemiology and toxicology, and the 

new studies discussed in today’s 

proposal. EPA solicits any additional 

cancer epidemiology and toxicology 

data that need to be considered for the 

final Stage 2 DBPR. 

EPA also solicits any health 

information available to further assess 

risk to sensitive subpopulations, 

especially children and the elderly. 

IV. DBP Occurrence Within 

Distribution Systems 

New information on the occurrence of 

DBPs in distribution systems raises 

issues about the protection provided by 

the Stage 1 DBPR. This section presents 

the new information used to identify 

key issues and to support the 

development of the Stage 2 DBPR. For 

a more detailed discussion see the Stage 

2 Occurrence Assessment for 

Disinfectants and Disinfection 

Byproducts (USEPA 2003o). 

Under the Stage 1 DBPR, compliance 

with the DBP MCLs is determined by 

averaging, annually and system-wide, 

all DBP measurements. The following 

discussion shows that compliance based 

on system averages of DBP 

concentrations allows a significant 

number of sampling locations within 

distribution systems to have DBP levels 

above the MCLs. These peak DBP 

occurrences are masked by averaging 

with lower distribution system 

occurrence levels. The populations 

served by portions of the distribution 

system with higher DBP concentrations 

are not receiving the same level of 

health protection. 

The new information also shows that 

the highest DBP levels often do not 

occur at distribution system sites 

identified as representing maximum 

residence time. The information further 

shows that the highest TTHM and 

HAA5 levels often do not occur at the 

same site within the distribution 

system. These two findings suggest that 

it is appropriate to reevaluate the Stage 

1 DBPR compliance monitoring sites in 

order to target those sites with high DBP 

levels. EPA believes that distribution 

system compliance monitoring sites 

need to be reevaluated to ensure 

identification of sites that reflect both 

high TTHM and HAA5 occurrence.

A. Data Sources 

1. Information Collection Rule Data 

The Information Collection Rule 

(USEPA 1996a) established monitoring 

and data reporting requirements for 

large public water systems. Under the 

Information Collection Rule, systems 

serving at least 100,000 people were 

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related monitoring. The 18 months of 

required monitoring, which began in 

July 1997 and ended in December 1998, 

applied to 296 public water systems 

(500 treatment plants). 

The Information Collection Rule data 

show the national occurrence of: (1) 

Influent water quality parameters; (2) 

primary and secondary disinfectant use 

by the large plants; (3) occurrence of 

DBPs and DBP precursors in treatment 

plants, finished waters, and 

distributions systems; (4) microbial 

occurrence (in subpart H systems only); 

and (5) treatment plant monthly 

operation, and initial as well as final 

treatment plant design. The data were 

gathered after the Stage 1 DBPR was 

finalized (USEPA 1998c) but well before 

systems were required to meet Stage 1 

DBPR requirements. 

The Information Collection Rule 

required a significant investment for the 

water treatment industry, as well as for 

the EPA to analyze the data. Overall, the 

occurrence and treatment data collected 

under the Information Collection Rule, 

excluding microbial data, was estimated 

to cost systems $54 million (USEPA 

1996a). In addition, systems using 

source waters with high DBP precursor 

levels were required to conduct bench 

and pilot studies to evaluate the 

effectiveness of granular activated 

carbon (GAC) and membrane technology 

to control for DBPs. The estimated cost 

for these studies totaled approximately 

$57 million (USEPA 1996a). 

In addition to the analysis of DBPs in 

distribution systems, EPA used 

occurrence data from the Information 

Collection Rule to confirm selection of 

TTHM and HAA5 as appropriate 

contaminants for monitoring DBPs. EPA 

also used occurrence data from the 

Information Collection Rule to confirm 

differences in monitoring requirements 

for systems using surface water versus 

those using ground water, as stipulated 

under the Stage 1 DBR. Analysis of the 

Information Collection Rule data 

indicates that TTHM and HAA5 

comprise on average, across all systems, 

about 50% of the total mixture of 

chlorinated DBPs and that TTHM and 

HAA5 concentrations are much lower 

and less variable in ground water 

systems than in surface water systems. 

These results support the basis for 

continuing the use of TTHM and HAA5 

as indicators for controlling chlorinated 

DBPs. The data also reconfirmed that 

ground water systems require less 

monitoring than surface water systems 

based on lower and less variable DBP 

occurrence. For detailed analysis, see 

Stage 2 Occurrence Assessment for 

Disinfectants and Disinfection 

Byproducts (USEPA 2003o). 

2. Other Data Sources Used To Support 

the Proposal 

Table IV–1 summarizes the data 

sources other than the Information 

Collection Rule used to support the 

Stage 2 DBPR. The data from the 

Information Collection Rule is from 

large systems. To validate the 

conclusions drawn from analysis of the 

Information Collection Rule for small 

and medium systems, EPA compared 

these other data sources with the 

Information Collection Rule data. EPA 

found that there are significant 

similarities between large systems and 

medium and small systems with regard 

to source water quality (affecting DBP 

formation) and use of treatment 

technologies. Because of these 

similarities, EPA expects that small and 

medium systems would find DBP 

distribution system levels similar to 

those found in large systems following 

compliance with the Stage 1 DBPR 

requirements. For detailed discussion of 

this analysis, see Stage 2 Occurrence 

Assessment for Disinfectants and 

Disinfection Byproducts (USEPA 2003o) 

and Economic Analysis for the Stage 2 

Disinfection Byproducts Rule (USEPA 

2003i).

TABLE IV–1.—SUMMARY OF NON-INFORMATION COLLECTION RULE OCCURRENCE SURVEY DATA

Data source Data collected Geographic representation Number of plants

(By population served) 

Information Collection Rule 

Supplemental Survey.

Raw source water-(Large Systems) TOC 

Raw source water-(Small & Medium Survey Systems) 

TOC, UV 254, bromide, turbidity, pH, & temperature. 

Random national distribution by SW source type 1.47 serving 100,000 or 

more. 

40 serving 10,000–99,999. 

40 serving fewer than 

10,000. 

WaterStats .......................... Population served and flows 

Raw source water—Water 

Quality Parameters (WQPs), 

Source water type. 

Finished water-WQPs, TTHM, HAAs 

Treatment-unit processes, disinfectant used. 

Random national distribution.219 serving 100,000 or 

more. 

623 serving 10,000–99,999. 

30 serving fewer than 

10,000. 

National Rural Water Association Survey (NRWAS).Population served and flows 

Raw source water-temperatures, turbidity, pH, and 

source water type, bromide, TOC, UV 254, alkalinity, calcium, and total hardness. 

Finished water-residence time estimate, total and individual THMs, individual HAAs and HAA5, HAA6, 

HAA9,TOC, UV 254, Bromide, Temperature, pH, 

free and total chlorine residual levels. 

Treatment-unit processes, disinfectant used. 

Random national distribution.117 serving fewer than 

10,000. 

State Data-Surface Water .. Distribution system TTHM occurrence data. AK, CA, IL, MN, MS, NC, 

TX, WA2.

562 serving fewer than 

10,000. 

State Data-Ground Water .. Distribution system TTHM occurrence data. AK, CA, FL, IL, NC, TX, 

WA2.

2336 serving fewer than 

10,000. 

Ground Water Supply Survey.TOC and TTHM (one sample for each parameter at 

the entry point to distribution system.) 

Random national distribution.979 total. 

1Source type designations include flowing stream and lake/reservoir (Except for 7 large plants pre-selected). 

2Over 50 percent of each State’s systems are represented. EPA believes that the data reasonably represent a full range of source water quality in small systems at the national level. 

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B. DBPs in Distribution Systems

EPA wanted to understand DBP 

occurrence in distribution systems 

likely to exist after implementation of 

the Stage 1 DBPR. Such an 

understanding would enable EPA to 

recognize options on how to improve 

protection under the Stage 2 DBPR. The 

analysis of occurrence data to support 

the Stage 2 DBPR is complicated 

because available national occurrence 

data do not reflect the changes in 

occurrence resulting from the 

implementation of the Stage 1 DBPR. 

Many utilities have only recently 

changed their treatment to comply with 

the Stage 1 DBPR (subpart H systems 

serving 10,000 people or more were 

required to comply beginning January 

2002) or are about to make changes in 

treatment to comply with this rule 

(subpart H systems serving fewer than 

10,000 people and ground water 

systems are required to comply 

beginning January 2004). 

To address the above issue, EPA 

evaluated Stage 1 DBPR implications by 

using Information Collection Rule data 

from plants that would not exceed the 

Stage 1 DBPR TTHM and HAA5 MCLs 

as an annual average. The TTHM and 

HAA5 data consist of quarterly 

measurements in four locations in 

distribution systems associated with 

each Information Collection Rule 

treatment plant. Two samples were 

collected at sites representing average 

residence time (AVG1 and AVG2), one 

sample at a site intended to represent 

the maximum residence time (MAX), 

and one sample was reported as a 

distribution system equivalent (DSE). 

The DSE sample was generally 

representative of average residence 

times. EPA believes that the monitoring 

locations of the Information Collection 

Rule, while not necessarily being the 

same as the Stage 1 DBPR compliance 

monitoring sites, provide a close 

approximation of monitoring under the 

Stage 1 DBPR. EPA recognizes, however, 

that data for plants that are in 

compliance with Stage 1 MCLs even 

without installing additional treatment 

(perhaps because of low source water 

TOC) are not necessarily reflective of 

plants that make treatment changes to 

comply with the Stage 1 DBPR. 

1. DBPs Above the MCL Occur at Some 

Locations in a Substantial Number of 

Plants 

Figure IV–1 compares the TTHM 

running annual average (RAA) levels 

with the single highest TTHM 

concentration in the distribution 

system. Twenty one percent (60 of 290) 

of the Information Collection Rule 

plants had single TTHM concentrations 

higher than the 0.080 mg/L MCL. Figure 

IV–2 makes the same comparison for 

HAA5. Fourteen percent (40 of 290) of 

the plants meeting the Stage 1 DBPR 

MCL had single HAA5 concentrations 

higher than the 0.060 mg/L MCL. In 

systems with a low RAA for TTHM and 

HAA5, the highest single TTHM and 

HAA5 values are generally not much 

higher than the respective Stage 1 DBPR 

MCLs. However, as the RAAs increase, 

there is a greater likelihood of having 

peak levels above the MCLs. As the 

RAAs approach the Stage 1 DBPR MCLs, 

some of the distribution system single 

highest concentrations approach levels 

that are double the Stage 1 DBPR MCLs. 

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2. Specific Locations in Distribution 

Systems Are Not Protected to MCL 

Levels 

Data from the Information Collection 

Rule show that the RAA compliance 

calculation may allow specific locations 

in a distribution system to regularly 

receive water with DBP levels that 

exceed the MCL. Figure IV–3 shows that 

five percent of plants (15 out of 290) had 

one or more locations that, on average, 

exceeded 0.080 mg/L as a TTHM LRAA 

for that same year. One of the 15 plants 

that exceeded a TTHM LRAA of 0.080 

mg/L did so at two locations. Of the 15 

plants, the highest LRAA was between 

0.080 and 0.090 mg/L at 10 plants, and 

between 0.090 and 0.100 mg/L at 5 

plants. Customers served at these 

locations regularly received water with 

TTHM concentrations somewhat higher 

than the MCL. 

Figure IV–4 shows similar results 

based on Information Collection Rule 

HAA5 data. Three percent of plants 

(eight of 290) exceeded 0.060 mg/L as an 

LRAA, and three of these eight plants 

did so at two or three locations. Of the 

8 plants, the highest LRAA was between 

0.060 and 0.070 mg/L at 5 plants, and 

between 0.070 and 0.075 mg/L at 3 

plants. Among the 290 plants in the 

Information Collection Rule database 

meeting the Stage 1 MCLs, 19 plants 

have a maximum TTHM LRAA of 0.080 

mg/l or greater or a maximum HAA5 

LRAA of 0.060 mg/l or greater (four 

plants exceeded both MCLs), though in 

no case did DBP levels at a given 

location consistently exceed the MCL by 

more than 20%.

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3. Stage 1 DBPR Maximum Residence 

Time Location May Not Reflect the 

Highest DBP Occurrence Levels 

The 1979 TTHM rule and Stage 1 

DBPR monitoring locations must 

include a site reflection maximum 

residence time in the distribution 

system with the intent of capturing the 

highest DBP levels in the distribution 

system. The Information Collection rule 

referred to this specific location as 

MAX. The Information Collection rule 

data indicate two important results: (1) 

that monitoring locations identified as 

the maximum residence time locations 

often did not represent those locations 

with the highest DBP levels and (2) the 

highest TTHM and HAA5 level often 

occurred at different points in the 

distribution system. 

Figure IV–5 illustrates that the highest 

TTHM and HAA5 LRAAs could be at 

any of the four Information Collection 

Rule sample locations in the 

distribution system or, in some cases, at 

the finished water location. Fifty 

percent of the plants evaluated have the 

highest TTHM LRAA concentration 

occurring at a site other than the 

maximum residence time monitoring 

site. over 60% of plants evaluated had 

the highest HAA5 LRAA at a location 

other than the maximum residence time 

monitoring site. 

Figure IV–6, based on data from the 

National Rural Water Survey (NRWS), 

indicates that systems serving fewer 

than 10,000 people also frequently have 

their highest TTHM and HAAS levels at 

locations other than those intended to 

represent maximum residence time. The 

occurrence patterns indicated in Figures 

IV–5 and IV–6 may be due to several 

factors, such as HHA5 degrading over 

time in the distribution system, 

maximum residence time monitoring 

sites not actually representing the 

maximum residence time, or that using 

a simple estimation of maximum 

residence time cannot characterize a 

complex distribution system.


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EPA also analyzed whether the 

highest LRAA for TTHM and HAA5 

occurred at the same location. If TTHM 

and HAA5 occur at the same location 

rather than different locations, fewer 

monitoring sites would be needed to 

represent TTHM and HAA5 occurrence. 

However, this is not the case. The 

Information Collection Rule and NRWA 

data sets, respectively, indicate that 

49% and 44% of plants experienced 

their highest LRAA TTHM and HAA5 

concentrations at different locations in 

the distribution system. 

For plants that did have their highest 

LRAA TTHM and HAA5 concentrations 

at the same location, it was not 

necessarily the maximum residence 

time monitoring location. Figure IV–7 

illustrates that for the Information 

Collection Rule plants with the highest 

TTHM and HAA5 levels occurring at the 

same location, the highest TTHM and 

HAA5 LRAA simultaneously occurred 

at the maximum residence time 

monitoring location in 50% of the cases. 

Figure IV–8 illustrates that for the 

NRWA plants with the highest TTHM 

and HAA5 levels occurring at the same 

location, the highest TTHM and HAA5 

LRAA simultaneously occurred at the 

maximum residence time (MAX) 

monitoring location in 64% of the cases. 

C. Request for Comment 

EPA requests comment on the 

analysis presented in this section. Is 

EPA’s approach for representing post 

Stage 1 DBPR occurrence appropriate? 

What other approaches might be used? 

Are the conclusions that EPA derives 

from the analysis appropriate?


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V. Discussion of Proposed Stage 2 DBPR 

Requirements 

A. MCLG for Chloroform 

1. What Is EPA Proposing Today? 

EPA is proposing an MCLG for 

chloroform of 0.07 mg/L based on a 

cancer reference dose (RfD), an 

assumption that a person drinks 2 liters 

of water per day (the 90th percentile of 

intake rate for the U.S. population), and 

a relative source contribution (RSC) of 

20 percent. The MCLG is proposed at a 

level at which no adverse effects on the 

health of persons is anticipated with an 

adequate margin of safety. This 

conclusion is based on toxicological 

evidence that the carcinogenic effects of 

chloroform are an ultimate consequence 

of sustained tissue toxicity. The MCLG 

is set at a daily dose for a lifetime at 

which no adverse effects will occur 

because the sustained tissue toxicity, 

which is a key event in the cancer mode 

of action of chloroform, will not occur 

(USEPA 2001b). 

EPA believes that the RfD used for 

chloroform is protective of sensitive 

groups, including children. This RfD 

was developed by the EPA current 

method for developing RfDs based on 

animal data. The method is designed to 

be protective by taking human 

variability into account and assuming 

that the average human will be as 

sensitive as the most responsive animal 

species. EPA’s understanding of the 

mode of action for chloroform does not 

indicate a uniquely sensitive subgroup 

or an increased sensitivity in children. 

2. How Was This Proposal Developed? 

a. Background. EPA proposed a zero 

MCLG for chloroform in the 1994 Stage 

1 DBPR proposal (USEPA 1994b). 

Following the proposal, numerous 

toxicological studies on chloroform 

were published and were discussed in 

two Notices of Data Availability 

(NODAs) (USEPA 1997a; USEPA 

1998e). The 1998 NODA presented 

substantial scientific data related to the 

mode of action as part of the chloroform 

risk assessment and requested comment 

on a chloroform MCLG of 0.3 mg/L that 

reflected a nonlinear mode of action. 

After considering comments on the 

NODAs, EPA determined that further 

deliberations with the Science Advisory 

Board (SAB) and stakeholders were 

needed before changing the MCLG for 

chloroform. Thus, EPA promulgated a 

chloroform MCLG of zero in the final 

Stage 1 DBPR (USEPA 1998c) and 

committed to conducting additional 

deliberations with the SAB and 

factoring the SAB’s review into the 

Agency’s Stage 2 DBPR rulemaking


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process. The Agency consulted with the 

SAB in October 1999 (USEPA 2000f). 

The Stage 1 DBPR MCLG of zero for 

chloroform was challenged, and the U.S. 

Court of Appeals for the District of 

Columbia Circuit issued an order 

vacating the zero MCLG (Chlorine 

Chemistry Council and Chemical 

Manufacturers Association v. EPA, 206 

f.3d 1286 (D.C. Circuit 2000)). EPA 

committed to the Court to propose a 

non-zero MCLG for chloroform in the 

upcoming proposed Stage 2 

Disinfectants and Disinfection 

Byproducts Rule. EPA removed the 

MCLG for chloroform from its Stage 1 

DBP NPDWR (USEPA 2000e). No other 

provision of the Stage 1 DBPR was 

affected.

b. Basis of the new chloroform MCLG. 

Based on an analysis of all the available 

scientific data on chloroform discussed 

in more detail below, EPA believes that 

chloroform dose-response is nonlinear 

and that chloroform is likely to be 

carcinogenic only under high exposure 

conditions. EPA’s assessment of the 

cancer risk associated with chloroform 

exposure (USEPA 2001b) uses the 

principles of the 1999 EPA Proposed 

Guidelines for Carcinogen Risk 

Assessment (USEPA 1999a). 

The Proposed Guidelines for 

Carcinogen Risk Assessment, as 

reviewed by the public and the EPA 

SAB, reflect new science and are 

consistent with, and an extension of, the 

existing 1986 Guidelines for Carcinogen 

Risk Assessment (USEPA 1986). The 

1986 guidelines provide for departures 

from default assumptions such as low 

dose linear extrapolation. For example, 

the 1986 EPA guidelines reflect the 

position of the Office of Science and 

Technology Policy (OSTP) that (OSTP 

1985; Principle 26) ‘‘[N]o single 

mathematical procedure is recognized 

as the most appropriate for low-dose 

extrapolation in carcinogenesis. When 

relevant biological evidence on 

mechanisms of action exists (e.g, 

pharmacokinetics, target organ dose), 

the models or procedure employed 

should be consistent with the 

evidence.’’ The 1985 guidelines go on to 

state ‘‘The Agency will review each 

assessment as to the evidence on 

carcinogenesis mechanisms and other 

biological or statistical evidence that 

indicates the suitability of a particular 

extrapolation model.’’

i. Mode of action. EPA has fully 

evaluated the science on chloroform and 

concludes that chloroform is likely to be 

carcinogenic to humans under high 

exposure conditions that lead to 

cytotoxicity and regenerative 

hyperplasia in susceptible tissue; 

chloroform is not likely to be 

carcinogenic to humans at a dose level 

that does not cause cytotoxicity and cell 

regeneration (USEPA 1998e, USEPA 

1998b, USEPA 2001b). 

Chloroform’s carcinogenic potential is 

indicated by animal tumor evidence 

(liver tumors in mice and renal tumors 

in both mice and rats) from inhalation 

and oral exposure. Data on metabolism, 

toxicity, mutagenicity and cellular 

proliferation contribute to an 

understanding of the mode of 

carcinogenic action. For chloroform, 

sustained or repeated cytotoxicity with 

secondary regenerative hyperplasia 

precedes, and is a key event for, hepatic 

and renal neoplasia. 

EPA believes that a DNA reactive 

mutagenic mode of action is not likely 

to be the predominant influence of 

chloroform on the carcinogenic process. 

EPA has concluded that the 

predominant mode of action involves 

cytotoxicity produced by the oxidative 

generation of highly reactive 

metabolites, followed by regenerative 

cell proliferation (USEPA 2001b). EPA 

further believes that the chloroform 

dose-response is nonlinear. The SAB 

final report states ‘‘(t)he Subcommittee 

agrees with EPA that sustained or 

repeated cytotoxicity with secondary 

regenerative hyperplasia in the liver 

and/or kidney of rats and mice 

precedes, and is probably a causal factor 

for, hepatic and renal neoplasia’’

(USEPA 2000f). 

ii. Metabolism. The cytochrome P450 

isoenzyme CYP 2E1 is the primary 

enzyme catalyzing chloroform 

metabolism at low concentrations. 

Chloroform’s carcinogenic effects 

involve oxidative generation of reactive 

and toxic metabolites (phosgene and 

hydrochloric acid [HCl]) and thus are 

related to its noncancer toxicities (e.g., 

liver or kidney toxicities). The 

electrophilic metabolite phosgene could 

react with macromolecules such as 

phosphotidyl inositols or tyrosine 

kinases which in turn could potentially 

lead to interference with signal 

transduction pathways (i.e., chemical 

messages controlling cell division), thus 

leading to carcinogenesis. Likewise, it is 

also plausible that phosgene reacts with 

cellular phospholipids, peptides and 

proteins resulting in generalized tissue 

injury. Glutathione, free cysteine, 

histidine, methionine and tyrosine are 

all potential reactants for electrophilic 

agents. 

At high concentrations, chloroform 

may undergo reductive metabolism 

which forms reactive dichloromethyl 

free radicals. These free radicals can 

contribute to lipid peroxidation and 

cause cytotoxicity. 

c. How the MCLG is derived. EPA 

continues to recognize the strength of 

the science in support of a nonlinear 

approach for estimating the 

carcinogenicity of chloroform. This 

science was affirmed by the Chloroform 

Risk Assessment Review Subcommittee 

of the EPA SAB Executive Committee 

which met on October 27–28, 1999 

(USEPA 2000f). The SAB Subcommittee 

agreed that the nonlinear approach is 

most appropriate for the risk assessment 

of chloroform. 

Nonzero MCLGs are scientifically and 

statutorily supported. The statute 

requires that the MCLG be set where no 

known or anticipated adverse effects 

occur, allowing for an adequate margin 

of safety (56 FR 3533; USEPA 1991b). 

Historically, EPA established MCLGs of 

zero for known or probable human 

carcinogens based on the principle that 

any exposure to carcinogens might 

represent some finite level of risk. If 

there is substantial scientific evidence, 

however, that indicates there is a ‘‘safe 

threshold’’, then a nonzero MCLG can 

be established with an adequate margin 

of safety (56 FR 3533; USEPA 1991a)).

EPA would ideally like to use the 

delivered dose (i.e., the amount of key 

chloroform metabolites that actually 

reach the liver and cause cell toxicity) 

for calculating an RfD to support the 

MCLG. However, the required 

toxicokinetic data are not currently 

available. Thus, the RfD is calculated 

using the applied dose (i.e., the amount 

of chloroform ingested). The RfD is 

based on both the benchmark dose and 

the traditional no observed adverse 

effect level/lowest observed adverse 

effect level (NOAEL/LOAEL) 

approaches for hepatotoxicity in the 

most sensitive species, the dog. The 

MCLG is based on the RfD and 

calculated as follows:

MCLG RfD body weigh

daily wate = × ×t RSCr consumption

i. Reference dose. The RfD for 

chloroform was estimated based on 

noncancer effects using both the 

benchmark dose and the traditional 

NOAEL/LOAEL approaches. For 

benchmark analysis, five relevant data 

sets including target organ toxicity, 

labeling index, histopathology in 

rodents, and liver toxicity in dogs 

(Heywood 1979) were evaluated. The 

effects seen in dogs are considered to be 

early signs of liver toxicity, preceding 

cytotoxicity, cytolethality and 

regenerative hyperplasia. Thus, the 

Heywood (1979) study, provides the 

most sensitive end point in the most 

sensitive species and is the most 

appropriate basis for the RfD.


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The 95% confidence lower bound on 

the dose associated with a 10% extra 

risk (LED10) is based on the prevalence 

of animals demonstrating liver toxicity. 

After an exposure adjustment to the 

LED10 (1.2 mg/kg/day), an RfD of 0.01 

mg/kg/day was calculated using an 

overall uncertainty factor of 100 (10 for 

interspecies extrapolation and 10 for 

protection of sensitive individuals) 

(USEPA 2001b). 

Coincidentally, the benchmark dose 

and the traditional NOAEL/LOAEL 

approaches yield the same RfD number 

(USEPA 2001b). The NOAEL/LOAEL 

approach is also based on the Heywood 

study (1979) which had a LOAEL of 15 

mg/kg/day for evidence of liver toxicity. 

After an exposure adjustment to the 

LOAEL (yielding 12.9 mg/kg/day), an 

RfD of 0.01 mg/kg/day was calculated 

using an overall uncertainty factor of 

1000 (10 for interspecies extrapolation, 

10 for protection of sensitive 

individuals, and 10 for using a LOAEL 

instead of a NOAEL) (USEPA 2001b). 

ii. Relative source contribution.

Another factor in determining the 

MCLG is the relative source 

contribution (RSC). The RSC is used 

when the MCLG is set at a level above 

zero. Its purpose is to ensure that the 

contribution to exposure from drinking 

tap water does not cause the lifetime 

daily exposure of persons to a 

contaminant to exceed RfD. The RSC is 

thus a factor used to make sure that the 

MCLG is protective even if persons are 

exposed to the contaminant by other 

routes (inhalation, dermal absorption) or 

other sources (e.g., food). If sufficient 

quantitative data are not available on 

exposure by other routes and sources, 

EPA has historically assumed that the 

RSC from drinking water is 20 percent 

of the total exposure, a value considered 

protective. If data indicate that 

contributions from other routes and 

sources are not significant, EPA has 

historically assumed a less conservative 

RSC of 80 percent (54 FR 22,062, 22,069 

(May 22, 1989)(USEPA 1989a), 56 FR at 

3535 (Jan 30, 1990)(USEPA 1991a), 59 

FR 38,668, 38,678 (July 29, 

1994)(USEPA 1994b)). 

Today, EPA is proposing an 

assumption of a 20 percent RSC. This is 

in consideration of data which indicate 

that exposure to chloroform by other 

routes and sources of exposure may 

potentially contribute a substantial 

percentage of the overall exposure to 

chloroform. 

In the 1998 Stage 1 DBPR NODA, EPA 

considered an MCLG of 0.3 mg/L that 

was calculated using an RSC of 80 

percent, based on the assumption that 

most exposure to chloroform is likely to 

come from ingestion of drinking water. 

In the final Stage 1 DBPR, EPA 

reconsidered this assumption in 

response to comments and in the light 

of data which indicate that exposure to 

chloroform by inhalation and dermal 

exposure may potentially contribute a 

substantial percentage of the overall 

exposure to chloroform depending on 

the activity patterns of individuals 

(USEPA 1998e) e.g., during showering, 

bathing, swimming, boiling water, 

clothes washing, and dishwashing. 

There is also potential exposure to 

chloroform by the dietary route. There 

are uncertainties regarding other 

possible highly exposed subpopulations, e.g., swimmers, those who 

use humidifiers, hot-tubs, and outdoor 

misters, persons living near industrial 

sources, people working in 

laundromats, and persons working with 

pesticides employing chloroform as a 

solvent (USEPA 1998b). 

A 1998 International Life Sciences 

Institute (ILSI) report evaluated the 

uptake of drinking water contaminants 

through the skin and by inhalation. The 

report noted that ‘‘(i)n the case of 

chloroform, its high volatility leads to 

its rapid movement from liquid to air. 

Large water-use sources, such as 

showers, become dominant sources with 

respect to exposure’’ and ‘‘(t)he 

inhalation route is demonstrated to be 

the primary route for higher-volatility 

compounds (e.g., chloroform)’’ (ILSI 

1998). Weisel and Jo (1996) found that 

‘‘approximately equivalent amounts of 

chloroform from water can enter the 

body by three different exposure routes, 

inhalation, dermal absorption, and 

ingestion, for typical daily activities of 

drinking and bathing.’’

Chloroform has been found in 

beverages, especially soft drinks, and 

food, particularly dairy products 

(Wallace, 1997). Wallace states that 

‘‘ingestion (drinking tap water and soft 

drinks and eating certain dairy foods), 

inhalation (breathing peak amounts of 

chloroform emitted during showers or 

baths, and lower levels in indoor air 

from other indoor sources), and dermal 

absorption (during showers, baths, and 

swimming)’’ each ‘‘appear to be 

potentially substantial contributors to 

total exposure’’.

EPA estimates that for the median 

individual, ingestion of total tap water 

(assuming certain activity patterns, 

habits, and home characteristics) can 

contribute roughly 28 percent of the 

total dose of chloroform (USEPA 2001a). 

With assumptions as described, tap 

water ingestion is a portion of exposure 

through fluid intake which contributes 

about 34 percent of the total dose, 

inhalation accounts for about 31 percent 

of the total dose, ingestion of foods 

contributes another 27 percent of the 

overall dose, and dermal absorption 

(primarily during showering) adds 

slightly less than 8 percent of the total 

dose. These exposure percentages are 

based on average daily doses (mean 

chloroform intake for adults) for each 

source and route of exposure under 

specific conditions. They do not take 

into account the considerable variability 

in several factors across the population. 

For instance, intake of drinking water or 

particular foods and length of shower 

varies from day-to-day, as do home air 

turnover rates and ventilation. Different 

areas in the United States vary with 

respect to these factors and chloroform 

concentrations in food. Thus, although 

the 28 percent for the median individual 

is based on reasonable assumptions, 

uncertainty remains. 

Given the uncertainties of estimation, 

EPA believes available analyses point to 

the RSC of 20 percent as the appropriate 

default (i.e., 20 percent of exposure to 

chloroform comes from drinking tap 

water alone). EPA also believes that this 

default is protective of public health 

and is a more reasonable choice than 

choosing any particular estimate 

because of the assumptions and 

uncertainties involved with each 

estimation. Hence, EPA is proposing the 

MCLG based on the RSC default of 20 

percent which supports the adequacy of 

the margin of safety associated with the 

MCLG. 

iii. Water ingestion and body weight 

assumptions. In MCLG calculations, 

EPA assumes the 90th percentile water 

ingestion of 2 liters (roughly equivalent 

to a half gallon) per day (USEPA 2000a). 

The use of a conservative consumption 

estimate is consistent with the objective 

of setting an MCLG that is protective. 

EPA also uses a default adult body 

weight of 70 kg (equal to 154 pounds) 

for the RfD since dose is calculated from 

lifetime studies of animals and 

compared to lifetime exposure for 

humans. 

iv. MCLG calculation. The MCLG is 

calculated to be 0.07 mg/L using the 

following assumptions: an adult tap 

water consumption of 2 L per day for a 

70 kg adult, and a relative source 

contribution of 20%:

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49579

MCLG for C

L day

hloroform = 0.01 mg/kg/d 70 kg 0.2 mg/L (rounded) × × = 20 07

/ .

EPA concludes that an MCLG of 0.07 

mg/L based on protection against liver 

toxicity will be protective against 

carcinogenicity given that the mode of 

action for chloroform involves 

cytotoxicity as a key event preceding 

tumor development. Therefore, the 

recommended MCLG for chloroform is 

0.07 mg/L. 

v. Other considerations. The evidence 

supports similarity of potential response 

in children and adults. The basic 

biology of toxicity caused by cell 

damage due to oxidative damage is 

expected to be the same. There is 

nothing about the incidence and 

etiology of liver and kidney cancer in 

children to indicate that they would be 

inherently more sensitive to this mode 

of action. Most importantly in this case, 

children appear to be no different 

quantitatively in ability to carry out the 

oxidative metabolism step for the 

induction of toxicity and cancer and 

may, as fetuses, be less susceptible 

(USEPA 1999c). 

Some commenters on the March 1998 

NODA were concerned that EPA did not 

take drinking water epidemiology 

studies into account in its evaluation of 

chloroform risk. EPA believes that while 

the epidemiologic evidence suggests 

that chlorinated drinking water may be 

associated with certain cancers and 

reproductive, developmental effects 

pertinent to the risk of disinfectant 

byproduct mixtures, it does not provide 

insight into the risk from chloroform 

specifically. The SAB noted that ‘‘(t)he 

goal of the draft risk assessment (the 

isolation of the effect of chloroform in 

drinking water) makes the extensive 

epidemiologic evidence on drinking 

water disinfection byproducts largely 

irrelevant’’ to the specific question of 

chloroform health risks because, in the 

available studies, chloroform cannot be 

isolated from other disinfection 

byproducts that may be in the drinking 

water (USEPA 2000f). The SAB noted 

that ‘‘the epidemiologic evidence is 

quite pertinent to the broader question 

of most direct regulatory concern, 

namely disinfection byproducts in the 

aggregate’’. 

d. Feasibility of other options. During 

the development of the MCLG for 

chloroform, EPA considered a number 

of options for both the chloroform 

MCLG and the TTHM MCL. Today, EPA 

is proposing the preferred option of a 

0.07 mg/L MCLG for chloroform. EPA 

primarily considered two other options 

which are discussed in more detail later: 

a 0.07 mg/L MCLG for chloroform in 

conjunction with developing MCLs for 

each of the individual TTHMs (i.e., 4 

MCLs and 4 MCLGs for the THMs); and 

developing a single combined MCLG for 

TTHM rather than developing a separate 

MCLG for each of the THMs. 

EPA considered developing separate 

MCLGs and MCLs for each THM. Under 

this strategy, EPA would determine an 

MCL as close to the individual MCLGs 

as is technically feasible, taking cost 

into consideration, for each THM. EPA 

would propose an MCLG of 0.07 mg/L 

for chloroform and maintain the Stage 1 

DBPR MCLGs for BDCM, DBCM, and 

bromoform (USEPA 1998c). EPA 

analyzed the impact such an MCL 

strategy would have and ultimately 

rejected this option. This approach 

represents a fundamental shift from the 

TTHM strategy agreed to by 

stakeholders and EPA as part of the M–

DBP negotiation process and reflected in 

the 1998 Stage 1 DBPR. In addition, one 

important component of the existing 

single MCL is that TTHMs are an 

indicator for other DBPs. Developing a 

separate MCL for each THM would 

move away from this indicator 

approach. Because precursor and DBP 

occurrence measurements are highly 

variable, both temporally and 

geographically, determining technical 

feasibility for best available technology 

(BAT) would be difficult. Compliance 

with individual THM standards would 

be very different from compliance based 

on a sum of the four THMs and it is not 

clear what treatment technology shifts 

would be needed. This problem would 

be particularly exacerbated in areas with 

high bromide, such as California. EPA 

also projected that States would have a 

difficult time overseeing (e.g., variances, 

exemptions, etc.) the more complicated 

rule that would result from this option.

EPA considered establishing a single 

combined MCLG for TTHM. There is 

precedent for using a toxicity 

equivalency quotient (analogous to a 

combined MCLG) for dioxin and 

coplanar PCBs (USEPA 2000o, Draft 

Dioxin Reassessment). From a scientific 

standpoint, a combined MCLG approach 

requires that the chemicals have a 

similar mode of action and health 

endpoint. Chemicals within each of the 

dioxin and coplanar PCB classes have 

the same mode of action and endpoint 

(target tissue). Within the PCB class, 

noncoplanar PCBs have a different 

mode of action than the coplanar PCBs. 

Noncoplanar PCBs are, therefore, not 

included in the toxicity equivalency 

quotient for coplanar PCBs. In the case 

of the disinfection byproducts, EPA 

believes that the THMs have different 

modes of action and health endpoints. 

One of the THMs is a liver carcinogen 

(chloroform) with a mode of action 

dependent on cytolethality; two are 

DNA-reactive carcinogens 

(bromodichloromethane—large intestine 

and kidney tumors, and bromoform—

large intestine tumors); and one is a 

nonlinear non-carcinogen 

(dibromochloromethane) which is a 

liver toxicant. EPA therefore, chose not 

to develop a combined MCLG for 

TTHM. Consequently, after considering 

this alternative option in some detail, 

EPA is today proposing an MCLG of 

0.07 mg/L for chloroform. 

3. Request for Comment 

Based on the information presented 

previously, EPA is proposing an MCLG 

for chloroform of 0.07 mg/L. EPA 

requests comments on the MCLG and on 

EPA’s cancer assessment for chloroform. 

EPA also requests comments on the RfD, 

the default RSC of 20 percent, and the 

tap water consumption and body weight 

assumptions used in the MCLG 

calculation. EPA solicits additional data 

on chloroform exposure via other 

sources and routes. EPA requests 

comment on the other options for 

developing the chloroform MCLG that 

the Agency considered. 

B. MCLGs for THMs and HAAs 

1. What Is EPA Proposing Today? 

Today EPA is proposing new MCLGs 

of 0.02 mg/L for TCAA and 0.03 mg/L 

for MCAA based on new toxicological 

data. As a part of the Stage 1 DBPR, EPA 

finalized an MCLG of 0.3 mg/L for 

TCAA. The Stage 1 DBPR did not 

include an MCLG for MCAA (although 

it was included as one of the five 

haloacetic acids in the HAA5 MCL). 

With the exception of chloroform, 

discussed above, and these two HAAs, 

EPA is not revising any of the other 

MCLGs that were finalized in the Stage 

1 DBPR. No significant new studies that 

would change EPA’s MCLG estimates 

for BDCM, DBCM, bromoform, or DCAA 

have been published since the Stage 1 

DBPR. See section III for a summary of 

new health effects data. 

2. How Was This Proposal Developed? 

EPA reviewed the available literature 

on BDCM, DBCM, bromoform, DCAA 

and determined that there was no new


EP18au03.027</MATH>
49580 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

information that would cause EPA to 

revise its MCLG estimates. New 

toxicology studies on reproductive and 

developmental effects and cancer are 

summarized in sections III.B. and III.D. 

of today’s proposal. 

EPA is proposing new MCLGs for 

TCAA and MCAA. The health effects 

information and studies described in the 

following two sections that support the 

proposed MCLGs are summarized from 

the Addendum to the Criteria Document 

for Monochloroacetic Acid and 

Trichloroacetic Acid (USEPA 2003b). 

The occurrence of MCAA and TCAA are 

discussed in the Stage 2 Occurrence 

Assessment for Disinfectants and 

Disinfection Byproducts (USEPA 

2003o). a. Trichloroacetic acid. In the 

final Stage 1 DBPR, EPA based its health 

effects assessment of TCAA on 

developmental toxicity and limited 

evidence of carcinogenicity (USEPA 

1998c). Since then, the Agency has 

decided that the RfD based on a 

developmental LOAEL yields a less 

conservative RfD than that based on 

liver toxicity derived from the study by 

DeAngelo et al. (1997). Thus, the 

Agency has reassessed the health effects 

of TCAA based on liver toxicity and 

revised the RfD and MCLG. 

TCAA induces systemic, noncancer 

effects in animals and humans that can 

be grouped into three categories: 

metabolic alterations, liver toxicity; and 

developmental toxicity. The primary 

site of TCAA toxicity is the liver 

(USEPA1994a; Dees and Travis, 1994; 

Acharya et al. 1995; Acharya et al. 1997; 

DeAngelo et al.1997). 

The liver has consistently been 

identified as a target organ for TCAA 

toxicity in short-term (Goldsworthy and 

Popp, 1987; DeAngelo et al. 1989; 

Sanchez and Bull, 1990) and longerterm (Bull et al. 1990; Mather et al.

1990; Bhat et al. 1991) studies. 

Peroxisome proliferation has been a 

primary endpoint evaluated, with mice 

reported to be more sensitive to this 

effect than rats. More recent studies 

have confirmed these earlier findings. 

TCAA-induced peroxisome proliferation 

was observed in B6C3F1 mice exposed 

for 10 weeks to doses as low as 25 mg/

kg/day (Parrish et al. 1996), while in rats 

exposed to TCAA for up to 104 weeks 

(DeAngelo et al. 1997), peroxisome 

proliferation was observed at 364 mg/

kg/day, but not at 32.5 mg/kg/day. 

Increased liver weight and significant 

increases in hepatocyte proliferation 

have been observed in short-term 

studies in mice at doses as low as 100 

mg/kg/day (Dees and Travis, 1994), but 

no increase in hepatocyte proliferation 

was noted in rats given TCAA at similar 

doses (DeAngelo et al. 1997). More 

clearly adverse liver toxicity endpoints, 

including increased serum levels of 

liver enzymes (indicating leakage from 

cells) or histopathological evidence of 

necrosis, have been reported in rats, but 

generally only at high doses. For 

example, in a rat chronic drinking water 

study, increased hepatocyte necrosis 

was observed at a dose of 364 mg/kg/

day (DeAngelo et al. 1997). 

In the DeAngelo et al.(1997) study, 

groups of 50 male F344 rats were 

administered TCAA in drinking water, 

at 0, 50, 500, or 5000 mg/L, resulting in 

time-weighted mean daily doses of 0, 

3.6, 32.5, or 364 mg/kg for 104 weeks. 

There were no significant differences in 

water consumption or survival between 

the control and treatment groups. 

Exposure to the high dose of TCAA 

resulted in a significant decrease in 

body weight of 11% at the end of the 

study. The absolute but not relative liver 

weight was decreased at the high dose. 

Complete necropsy and histopathology 

examination showed mild hepatic 

cytoplasmic vacuolization in the two 

low-dose groups, but not in the highdose group. The severity of hepatic 

necrosis was increased mildly in the 

high-dose animals. Analyses of serum 

aspartate aminotransferase (AST) and 

alanine aminotransferase (ALT) 

activities at the end of exposure showed 

a significant decrease in AST activity in 

the mid-dose group and a significant 

increase in ALT level in the high-dose 

group. Since increased serum ALT or 

AST levels reflect hepatocellular 

necrosis, the increased ALT at the high 

dose is considered an adverse effect, 

while a non-dose related decrease of 

AST is not. Peroxisome proliferation 

was increased significantly in the highdose animals. There was no evidence of 

any exposure-related increase in 

hepatocyte proliferation. Based on the 

significant decrease in body weight 

(≥10%), minimal histopathology 

changes, and increased serum ALT 

level, the high dose of 364 mg/kg/day is 

considered the LOAEL and the mid dose 

of 32.5 mg/kg/day is considered the 

NOAEL. 

There are no reproductive toxicity 

studies of TCAA. The results of an in 

vitro fertilization assay indicated that 

TCAA might decrease fertilization 

(Cosby and Dukelow, 1992). The 

available data suggest that TCAA is a 

developmental toxicant. TCAA 

increased resorptions, decreased 

implantations, and increased fetal 

cardiovascular malformations when 

administered to pregnant rats at 291 mg/

kg/day (Johnson et al. 1998) on gestation 

days 1–22. In another study, decreased 

fetal weight and length, and increased 

cardiovascular malformations were 

observed when pregnant rats were 

administered 330 mg/kg/day TCAA by 

gavage during gestation days 6 to 15 

(Smith et al. 1989). Neither of these 

studies identified a NOAEL. The results 

of in vitro developmental toxicity 

assays, including mouse and rat wholeembryo culture (Saillenfait et al. 1995; 

Hunter et al. 1996) and frog embryo 

teratogenesis assay—Xenopus (FETAX) 

(Fort et al. 1993) yielded positive 

results. The Hydra test system (Fu et al.

1990) produced negative results. 

TCAA has been reported to induce 

liver tumors in mice but not in rats 

(USEPA 1994a). This observation has 

also been made in more recent drinking 

water studies. Pereira (1996) observed 

an increased incidence of hepatocellular 

adenomas and carcinomas in female 

B6C3F1 mice at doses of 262 mg/kg/day 

and higher after 82 weeks. In contrast, 

no increase in neoplastic liver lesions 

were found in F344 rats given doses up 

to 364 mg/kg/day for 104 weeks 

(DeAngelo et al. 1997). In addition, a 

variety of recent mechanistic studies 

have observed that TCAA either 

induced or promoted liver tumors in 

mice (Ferreira-Gonzalez et al. 1995; 

Pereira and Phelps, 1996; Tao et al.

1996; Latendresse and Pereira, 1997; 

Stauber and Bull, 1997; Tao et al. 1998).

Recent mutagenicity data have 

provided mixed results (Giller et al.

1997; DeMarini et al. 1994; HarringtonBrock et al. 1998). TCAA did not induce 

oxidative DNA damage in mice 

following dosing for either 3 or 10 

weeks (Parrish et al. 1996). Studies on 

DNA strand breaks and chromosome 

damage produced mixed results (Nelson 

and Bull, 1988; Chang et al. 1991; 

Mackay et al. 1995; Harrington-Brock et 

al. 1998). 

According to the 1999 Draft 

Guidelines for Carcinogen Risk 

Assessment (USEPA 1999a), a 

compound is appropriately classified as 

‘‘Suggestive Evidence of 

Carcinogenicity, but Not Sufficient to 

Assess Human Carcinogenic Potential’’

when ‘‘the evidence from human or 

animal data is suggestive of 

carcinogenicity, which raises a concern 

for carcinogenic effects but is judged not 

sufficient for a conclusion as to human 

carcinogenic potential’’. Based on 

uncertainty surrounding the relevance 

of the liver tumor data in B6C3F1 mice, 

TCAA can best be described as 

‘‘Suggestive Evidence of 

Carcinogenicity, but Not Sufficient to 

Assess Human Carcinogenic Potential’’

under the 1999 Draft Guidelines for 

Carcinogen Risk Assessment. Thus a 

quantitative estimate of cancer potency 

is not supported.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49581

The RfD for TCAA of 0.03 mg/kg/day 

is based on the NOAEL of 32.5 mg/kg/

day for liver histopathological changes 

identified by DeAngelo et al. (1997). 

The RfD includes an uncertainty factor 

of 1000 (composite uncertainty factor 

consisting of three factors of 10 chosen 

to account for extrapolation from a 

NOAEL in animals, inter-individual 

variability in humans, and 

insufficiencies in the database, 

including the lack of full 

histopathological data in a second 

species, the lack of a developmental 

toxicity study in second species, and the 

lack of a multi-generation reproductive 

study). 

The MCLG is calculated to be 0.02 

mg/L using the following assumptions: 

an adult tap water consumption of 2 L 

of tap water per day for a 70 kg adult, 

a relative source contribution (RSC) of 

20%, and an additional safety factor to 

account for possible carcinogenicity. 

EPA has traditionally applied an 

additional safety factor of 1–10 beyond 

the uncertainty factors included in the 

RfD to the MCLG to account for possible 

carcinogenicity in cases where there is 

limited evidence of carcinogenicity from 

drinking water, considering weight of 

evidence, pharmacokinetics, potency 

and exposure (USEPA 1994b, p.38678). 

EPA is proposing this additional safety 

factor of 10 for TCAA for the following 

reasons: TCAA causes liver tumors in 

mice but does not do so in rats. In 

addition, although peroxisome 

proliferation (a mode of action of 

limited relevance to humans) may play 

a role in the development of the mouse 

tumors, rats also exhibit a peroxisomal 

proliferative response after exposure to 

TCA, yet do not develop tumors. Other 

data suggest that promotion of initiated 

cells and/or disrupted cell signaling 

may be involved in the mode of action 

for the mouse tumors. Together these 

factors argue against quantification of 

the mouse liver tumors using linear 

extrapolation from the dose-response 

curve, but are not sufficient to rule out 

concern for a tumorigenic response. 

Accordingly, EPA has employed the tenfold additional safety factor in 

determination of the Lifetime Health 

Advisory for TCAA. EPA requests 

comment on the use of 10 as the 

additional safety factor for possible 

carcinogenicity.

MCLG for TCAA = (0.03 mg/kg/day)(70 kg)(20%)

 L/day)(10) 0.02 mg/L (rounded) (2 =

An RSC factor of 20% is used to 

account for exposure to TCAA in 

sources other than tap water, such as 

ambient air and food. Although TCAA 

is nonvolatile and inhalation while 

showering is not expected to be a major 

contribution to total dose, rain waters 

contain 0.01–1.0 μg/L of TCAA 

(Reimann et al. 1996) and it can be 

assumed to be detected in the 

atmosphere. Limited data on 

concentrations of TCAA in air (NATICH 

1993) indicate inhalation of TCAA in 

ambient air may contribute to overall 

exposure. Concentrations of TCAA that 

have been measured in a limited 

selection of foods including vegetables, 

fruits, grain and bread (Reimann et al.

1996) are comparable to that in water. 

About 3 to 33% of TCAA in cooking 

water have been reported to be taken up 

by the food during cooking in a recent 

research summary (Raymer et al. 2001). 

In addition, there are uses of chlorine in 

food production and processing, and 

TCAA may occur in food as a byproduct 

of chlorination (USEPA 1994a). 

Therefore, ingestion of TCAA in food 

may also contribute to the overall 

exposure. A recent dermal absorption 

study of DCAA and TCAA from 

chlorinated water suggested that the 

dermal contribution to the total doses of 

DCAA and TCAA from routine 

household uses of drinking water is less 

than 1% (Kim and Weisel, 1998). 

b. Monochloroacetic acid. Subchronic 

and chronic oral dosing studies suggest 

that the primary targets for MCAAinduced toxicity include the heart and 

nasal epithelium. In a 13-week oral 

gavage study, decreased heart weight 

was observed at 30 mg/kg/day and 

cardiac lesions progressed in severity 

with increasing dose. Liver and kidney 

toxicity were only observed at higher 

doses (NTP 1992). In a two-year study, 

decreased survival and nasal and 

forestomach hyperplasia were observed 

in mice at 50 mg/kg/day (NTP 1992). A 

more recent study confirms the heart 

and nasal cavities as target sites for 

MCAA. DeAngelo et al. (1997) noted 

decreased body weight at 26.1 mg/kg/

day and myocardial degeneration and 

inflammation of the nasal cavities in 

rats exposed to doses of 59.9 mg/kg/day 

for up to 104 weeks. 

No studies were located on the 

reproductive toxicity of MCAA and the 

potential developmental toxicity of 

MCAA has not been adequately tested. 

Two developmental toxicity studies 

were identified. Johnson et al. (1998) 

reported markedly decreased maternal 

weight gain, but no developmental 

effects, in rats exposed to 193 mg/kg/

day MCAA through gestation days 1–22, 

only fetal heart was examined. In 

contrast, in a published abstract, Smith 

et al. (1990) reported an increase in 

cardiovascular malformations when 

pregnant rats were exposed to 140 mg/

kg/day; this was also the LOAEL for 

maternal toxicity, based on marked 

decreases in weight gain. MCAA was 

noted as a potential developmental 

toxicant in in vitro screening assays 

using Hydra (Fu et al. 1990; Ji et al.

1998).

MCAA has yielded mixed results in 

genotoxicity assays (USEPA 1994a; 

Giller et al. 1997), but has not induced 

a carcinogenic response in chronic 

rodent bioassays (NTP 1992; DeAngelo 

et al. 1997). In chronic oral gavage 

studies, a LOAEL of 15 mg/kg/day (the 

lowest dose tested) for decreased 

survival was identified in rats. In mice 

the NOAEL was 50 mg/kg/day and the 

LOAEL was 100 mg/kg/day for nasal 

and forestomach epithelium hyperplasia 

(NTP 1992). In a more recent chronic 

study, DeAngelo et al. (1997) reported a 

LOAEL of 3.5 mg/kg/day in rats given 

MCAA in their drinking water, based on 

increased absolute and relative spleen 

weight. Although spleen weight was 

decreased at the mid and high doses, 

this might reflect the masking effect of 

overt toxicity. As evidence for this, 

decreased body weight (>10%), liver, 

kidney, and testes weight changes were 

reported beginning at the next higher 

dose of 26.1 mg/kg/day. No increased 

spleen weight was reported in the NTP 

(1992) bioassays, but the lowest dose in 

rats caused severe toxicity, and the 

lowest dose in mice was more than an 

order of magnitude higher than the 

LOAEL in the DeAngelo et al. (1997) 

study. 

According to the 1999 Draft 

Guidelines for Carcinogen Risk 

Assessment (USEPA 1999a), a 

compound is appropriately classified as 

‘‘Not Likely to be Carcinogenic to 

Humans’’ when it has ‘‘been evaluated 

in at least two well-conducted studies in 

two appropriate animal species without 

demonstrating carcinogenic effects.’’

MCAA can best be described as ‘‘Not 

Likely to be Carcinogenic to Humans’’

under the 1999 Draft Guidelines for 

Carcinogen Risk Assessment.


EP18AU03.024</MATH>
49582 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

The RfD for MCAA of 0.004 mg/kg/

day is based on a LOAEL of 3.5 mg/kg/

day for increased spleen weight in rats 

(DeAngelo et al. 1997) and application 

of an uncertainty factor of 1000 

(composite uncertainty factor consisting 

of two factors of 10 chosen to account 

for extrapolation from an animal study, 

and inter-individual variability in 

humans; as well as two factors of 3 for 

extrapolation from a minimal effect 

LOAEL, and insufficiencies in the 

database, including the lack of adequate 

developmental toxicity studies in two 

species, and the lack of a multigeneration reproductive study). Two 

developmental toxicity studies have 

been reported (Johnson et al. 1998; 

Smith et al. 1990), but the NOAELs 

yielded less conservative RfDs. The 

study by DeAngelo et al (1997) is the 

most appropriate for derivation of the 

RfD because it identifies the lowest 

LOAEL, and dosing was in drinking 

water, which is more appropriate for 

human health risk assessment. 

The MCLG is calculated to be 0.03 

mg/L using the following assumptions: 

an adult tap water consumption of 2 L 

of tap water per day for a 70 kg adult, 

and a relative source contribution of

20 %.

MCLG for MCAA = (0.004 mg/kg/day)(70 kg)(20%)

 L/day) 0.03 mg/L (rounded) (2 =

An RSC factor of 20% is used to 

account for exposure to MCAA in other 

sources in addition to tap water. 

Although MCAA is nonvolatile and 

inhalation while showering is not 

expected to be a major contribution to 

total dose, rain waters contain 0.05–9 

μg/L of MCAA (Reimann et al. 1996) 

and it can be assumed to be detected in 

the atmosphere. Presence of MCAA has 

also been reported in rain waters; thus, 

inhalation of MCAA in ambient air may 

contribute to overall exposure. 

Concentrations of MCAA that have been 

measured in a limited selection of foods 

including vegetables, fruits, grain and 

bread (Reimann et al. 1996) are 

comparable to that in water. About 2.5 

to 62% of MCAA in cooking water has 

been reported to be taken up by food 

during cooking in a recent research 

summary (Raymer et al. 2001). In 

addition, there are uses of chlorine in 

food production and processing, and 

MCAA may occur in food as a 

byproduct of chlorination (USEPA 

1994a). Therefore, ingestion of MCAA in 

food may also contribute to the overall 

exposure. Assuming dermal absorption 

rate of MCAA is similar to DCAA, 

dermal contribution to the total doses of 

MCAA from routine household uses of 

drinking water should be minor (see

V.B.2.a.). 

3. Request for Comment 

EPA requests comment on the new 

MCLGs for TCAA (0.02 mg/L) and 

MCAA (0.03 mg/L) and all the factors 

incorporated in the derivation of the 

MCLGs, including the RfDs and RSCs. 

EPA also solicits health effect 

information on DBAA and 

monobromoacetic acid (MBAA), for 

which MCLGs have not yet been 

established. 

C. Consecutive Systems 

Today’s proposal includes provisions 

for consecutive systems, which are 

public water systems that purchase or 

otherwise receive finished water from 

another water system (a wholesale 

system). As described in this section, 

consecutive systems face particular 

challenges in providing water that meets 

regulatory standards for DBPs and other 

contaminants whose concentration can 

increase in the distribution system. 

Moreover, current regulation of DBP 

levels in consecutive systems varies 

widely among States. In consideration 

of these factors, EPA is proposing 

monitoring, compliance schedule, and 

other requirements specifically for 

consecutive systems. These 

requirements are intended to facilitate 

compliance by consecutive systems 

with MCLs for TTHM and HAA5 under 

the Stage 2 DBPR. Further, this 

approach will help to ensure that 

consumers in consecutive systems 

receive equivalent public health 

protection. This section begins with a 

summary of how EPA proposes to 

regulate consecutive systems under the 

Stage 2 DBPR. The intent of this section 

is to provide an overview of all 

consecutive system requirements in 

today’s proposal. Detailed explanations 

of these requirements are provided in 

later sections of this preamble. The 

overview of consecutive system 

requirements is followed by an 

explanation of why EPA has taken this 

approach to consecutive systems in 

today’s proposal, including 

recommendations from the Stage 2 M–

DBP Federal Advisory Committee. 

1. What Is EPA Proposing Today? 

As public water systems, consecutive 

systems must provide water that meets 

the MCLs for TTHM and HAA5 under 

the proposed Stage 2 DBPR, and must 

carry out associated monitoring, 

reporting, recordkeeping, public 

notification, and other requirements. 

The following discussion summarizes 

how the Stage 2 DBPR requirements 

apply to consecutive systems, beginning 

with a series of definitions. Later 

sections of this preamble provide 

further details as noted. 

a. Definitions. To address consecutive 

systems in the Stage 2 DBPR, the 

Agency must define them, along with a 

number of related terms. 

EPA is proposing to define a 

consecutive system in the Stage 2 DBPR 

as a public water system that buys or 

otherwise receives some or all of its 

finished water from one or more 

wholesale systems for at least 60 days 

per year. In addition to buying finished 

water, some consecutive systems also 

operate a treatment plant (meaning a 

plant that treats source water to produce 

finished water). As described in section 

V.I., monitoring requirements under the 

Stage 2 DBPR proposal differ depending 

on whether a consecutive system buys 

all of its finished water year-round or, 

alternatively, produces some of its 

finished water through treating source 

water.

EPA proposes to define finished water 

as water that has been introduced into 

the distribution system of a public water 

system and is intended for distribution 

without further treatment, except that 

necessary to maintain water quality 

(such as booster disinfection). With this 

definition, water entering the 

distribution system is finished water 

even if a system subsequently applies 

additional treatment like booster 

disinfection to maintain a disinfectant 

residual throughout the distribution 

system. 

In today’s proposal, EPA defines a 

wholesale system as a public water 

system that treats source water and then 

sells or otherwise delivers finished 

water to another public water system for 

at least 60 days per year. Delivery may 

be through a direct connection or 

through the distribution system of 

another consecutive system. Under this 

definition, a consecutive system that 

passes water from a wholesaler to 

another consecutive system, and that 

does not also treat source water, is not


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a wholesale system. Rather, the system 

that actually produces the finished 

water is responsible for wholesale 

system requirements under the 

proposed Stage 2 DBPR. 

A consecutive system entry point is 

defined as a location at which finished 

water is delivered at least 60 days per 

year from a wholesale system to a 

consecutive system. Section V.I. 

presents the relationship between 

consecutive system entry points and 

proposed Stage 2 DBPR monitoring 

requirements. The combined 

distribution system is the 

interconnected distribution system 

consisting of the distribution systems of 

wholesale systems and of the 

consecutive systems that receive 

finished water from those wholesale 

system(s). 

b. Monitoring. For consecutive 

systems that both purchase finished 

water and treat source water to produce 

finished water for at least part of the 

year, EPA is proposing monitoring 

requirements under a treatment plantbased approach, described in section 

V.I. This is the approach proposed for 

non-consecutive systems under the 

Stage 2 DBPR as well. Under this 

approach, the sampling requirements for 

consecutive systems will be influenced 

by both the number of treatment plants 

operated by the system and the number 

of consecutive system entry points, as 

well as population served and source 

water type. 

For consecutive systems that purchase 

all of their finished water year-round, 

EPA is proposing monitoring 

requirements under a population-based 

approach, also described in section V.I. 

Under the population-based approach, 

the population of the consecutive 

system will determine the sampling 

requirements. EPA believes this 

approach is more appropriate than 

plant-based monitoring because these 

consecutive systems do not have 

treatment plants. As noted in section 

V.I., EPA is requesting comment on 

extending population-based monitoring 

to all systems, including nonconsecutive systems. EPA has prepared 

draft guidance for implementing the 

IDSE monitoring requirements 

(described in section V.H.) using the 

population-based approach (USEPA 

2003j). 

EPA is also proposing that States have 

the opportunity to specify alternative 

monitoring requirements for multiple 

consecutive systems in a combined 

distribution system. This option allows 

States to consider complex consecutive 

system configurations for which 

alternative monitoring strategies might 

be more appropriate. As a minimum 

under such an approach, each 

consecutive system must collect at least 

one sample among the total number of 

samples required for the combined 

distribution system and will base 

compliance on samples collected within 

its distribution system. The consecutive 

system is responsible for ensuring that 

required monitoring is completed and 

the system is in compliance. The 

consecutive system may conduct the 

monitoring itself or arrange for the 

monitoring to be done by the wholesale 

system or another outside party. 

Whatever approach it chooses, the 

consecutive system must document its 

monitoring strategy as part of its DBP 

monitoring plan. 

Finally, EPA is proposing that 

consecutive systems not conducting 

disinfectant residual monitoring comply 

with the monitoring requirements and 

MRDLs for chlorine and chloramines. 

c. Compliance schedules. EPA is 

proposing that consecutive systems of 

any size comply with the requirements 

of the Stage 2 DBPR on the same 

schedule as required for the largest 

system in the combined distribution 

system. This includes the schedule for 

carrying out the IDSE, described in 

section V.H, and for meeting the Stage 

2B MCLs for TTHM and HAA5, 

described in section V.D. As discussed 

later in this section, EPA is proposing 

simultaneous compliance schedules 

under the Stage 2 DBPR for all systems 

(both wholesalers and consecutive 

systems) in a combined distribution 

system because this may allow for more 

cost-effective compliance with TTHM 

and HAA5 MCLs. This is also consistent 

with the recommendations of the Stage 

2 M–DBP Advisory Committee. See 

section V.J for details of compliance 

schedule requirements. 

d. Treatment. While consecutive 

systems often do not need to treat 

finished water received from a 

wholesale system, they may need to 

implement procedures to control the 

formation of DBPs in the distribution 

system. For consecutive systems, EPA is 

proposing that the BAT for meeting 

TTHM and HAA5 MCLs is 

chloramination with management of 

hydraulic flow and storage to minimize 

residence time in the distribution 

system. This BAT stems from the 

recognition that treatment to remove 

already-formed DBPs or minimize 

further formation is different from 

treatment to prevent or reduce their 

formation. See section V.F for additional 

information on BATs and their role in 

compliance with MCLs. 

e. Violations. Under this proposal, 

monitoring and MCL violations are 

assigned to the PWS where the violation 

occurred. Several examples are as 

follows:

—If a consecutive system has hired its 

wholesale system under contract to 

monitor in the consecutive system 

and the wholesale system fails to 

monitor, the consecutive system is in 

violation because it has the legal 

responsibility for monitoring under 

State/EPA regulations. 

—If monitoring results in a consecutive 

system indicate an MCL violation, the 

consecutive systems is in violation 

because it has the legal responsibility 

for complying with the MCL under 

State/EPA regulations. The 

consecutive system may set up a 

contract with its wholesale system 

that details water quality delivery 

specifications. 

—If a wholesale system has a violation 

and provides that water to a 

consecutive system, the wholesale 

system is in violation. Whether the 

consecutive system is in violation will 

depend on the situation. The 

consecutive system will also be in 

violation unless it conducted 

monitoring that showed that the 

violation was not present in the 

consecutive system. 

f. Public notice and consumer 

confidence reports. The responsibilities 

for public notification and consumer 

confidence reports rest with the 

individual system. Under the Public 

Notice Rule and Consumer Confidence 

Report Rule, the wholesale system is 

responsible for notifying the 

consecutive system of analytical results 

and violations related to monitoring 

conducted by the wholesale system. 

Consecutive systems are required to 

conduct appropriate public notification 

after a violation (whether in the 

wholesale system or the consecutive 

system). In their consumer confidence 

report, consecutive systems must 

include results of the testing conducted 

by the wholesale system unless the 

consecutive system conducted 

equivalent testing that indicated the 

consecutive system was in compliance, 

in which case the consecutive system 

reports its own compliance monitoring 

results. 

g. Recordkeeping and reporting.

Consecutive systems are required to 

keep all records required of PWSs 

regulated under this rule. They are also 

required to report to the State 

monitoring results, violations, and other 

actions, and are required to consult with 

the State after a significant excursion.

h. State special primacy conditions.

EPA is aware that due to the 

complicated wholesale systemconsecutive system relationships that

49584 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

exist nationally, there will be cases 

where the standard monitoring 

framework proposed today will be 

difficult to implement. Therefore, the 

Agency is proposing to allow States to 

develop, as a special primacy condition, 

a program under which the State can 

modify monitoring requirements for 

consecutive systems. These 

modifications must not undermine 

public health protection and all 

systems, including consecutive systems, 

must comply with the TTHM and HAA5 

MCLs based on the LRAA. However, 

such a program would allow the State 

to establish monitoring requirements 

that account for complicated 

distribution system relationships, such 

as where neighboring systems buy from 

and sell to each other regularly 

throughout the year, water passes 

through multiple consecutive systems 

before it reaches a user, or a large group 

of interconnected systems have a 

complicated combined distribution 

system. EPA intends to develop a 

guidance manual to address 

development of a State program and 

other consecutive system issues. 

2. How Was This Proposal Developed? 

The practice of public water systems 

buying and selling water to each other 

has been commonplace for many years. 

Reasons include saving money on 

pumping, treatment, equipment, and 

personnel; assuring an adequate supply 

during peak demand periods; acquiring 

emergency supplies; selling surplus 

supplies; delivering a better product to 

consumers; and meeting Federal and 

State water quality standards. EPA 

estimates that there are at least 8500 

consecutive systems nationally, based 

on the definitions being proposed today. 

Consecutive systems face particular 

challenges in providing water that meets 

regulatory standards for contaminants 

that can increase in the distribution 

system. Examples of such contaminants 

include coliforms, which can grow if 

favorable conditions exist, and some 

DBPs, including THMs and HAAs, 

which can increase when a disinfectant 

and DBP precursors continue to react in 

the distribution system. 

EPA is proposing requirements 

specifically for consecutive systems 

because States have taken widely 

varying approaches to regulating DBPs 

in consecutive systems. For example, 

some States do not regulate DBP levels 

in consecutive systems that deliver 

disinfected water but do not add a 

disinfectant. Other States determine 

compliance with DBP standards based 

on the combined distribution system 

that includes both the wholesaler and 

consecutive systems. In this case, sites 

in consecutive systems are treated as 

monitoring sites within the combined 

distribution system. Once fully 

implemented, this proposed rule will 

ensure similar protection for consumers 

in consecutive systems. 

EPA is proposing that consecutive 

systems and wholesale systems be on 

the same compliance schedule because 

generally the most cost-effective way to 

achieve compliance with TTHM and 

HAA5 MCLs is to treat at the source, 

typically through precursor removal or 

alternative disinfectants. For a 

wholesale system to make the best 

decisions concerning the treatment 

steps necessary to meet TTHM and 

HAA5 LRAAs under the Stage 2 DBPR, 

both in its own distribution system and 

in the distribution systems of 

consecutive systems it serves, the 

wholesale system must know the DBP 

levels throughout the combined 

distribution system. Without this 

information, the wholesale system may 

design treatment changes that allow the 

wholesale system to achieve 

compliance, but leave the consecutive 

system out of compliance. EPA also 

recognizes that there may be cases 

where a consecutive system needs to 

add treatment even after a wholesale 

system has optimized its own treatment 

train. 

In consideration of these issues, the 

Stage 2 M–DBP Advisory Committee 

recognized two principles related to 

consecutive systems: (1) Consumers in 

consecutive systems should be just as 

well protected as customers of all 

systems, and (2) monitoring provisions 

should be tailored to meet the first 

principle. Accordingly, the Advisory 

Committee recommended that all 

wholesale and consecutive systems 

comply with provisions of the Stage 2 

DBPR on the same schedule required of 

the wholesale or consecutive system 

serving the largest population in the 

combined distribution system. In 

addition, the Advisory Committee 

recommended that EPA solicit 

comments on issues related to 

consecutive systems that the Advisory 

Committee had not fully explored 

(USEPA 2000g). EPA agrees with these 

recommendations and they are reflected 

in today’s proposal. 

3. Request for Comment 

EPA requests comment on all 

consecutive system issues related to this 

rule. Specifically, EPA requests 

comment on the following:

—Whether the proposed definitions 

adequately address various wholesale 

system-consecutive system 

relationships and issues. 

—Whether any additional terms need to 

be defined and, if so, what the 

definition should be. 

—Whether the criteria for States’ use of 

the special primacy criteria and other 

State responsibilities are appropriate 

and adequate. 

—Whether it is necessary to require that 

consecutive system treatment be 

installed on the same compliance 

schedule as the wholesale system in 

cases where the size of the 

consecutive system might otherwise 

allow it a longer compliance time 

frame and the consecutive system 

treatment does not affect water quality 

in any other system. 

D. MCLs for TTHM and HAA5 

1. What Is EPA Proposing Today?

Today, EPA is proposing use of 

locational running annual averages 

(LRAAs) to determine compliance with 

the MCLs for TTHM and HAA5. 

Consistent with the Stage 2 M-DBP 

Advisory Committee recommendation, 

EPA is proposing a phased approach for 

LRAA implementation to allow systems 

to identify compliance monitoring 

locations for Stage 2B while facilitating 

transition to the new compliance 

strategy and maintaining simultaneous 

compliance schedules for the Stage 2 

DBPR and the LT2ESWTR. 

In Stage 2A, all systems must comply 

with MCLs of 0.120 mg/L for TTHM and 

0.100 mg/L for HAA5 as LRAAs using 

Stage 1 DBPR compliance monitoring 

sites. In addition, during this time 

period, all systems must continue to 

comply with the Stage 1 DBPR MCLs of 

0.080 mg/L TTHM and 0.060 mg/L 

HAA5 as RAAs. 

In Stage 2B, all systems, including 

consecutive systems, must comply with 

MCLs of 0.080 mg/L TTHM and 0.060 

mg/L HAA5 as LRAAs using sampling 

sites identified under the Initial 

Distribution System Evaluation (IDSE) 

(discussed in section V.H.). 

Details of proposed monitoring 

requirements and compliance schedules 

are discussed in preamble sections V.I. 

and V.J., respectively, and may be found 

in § 141.136 and subpart V of today’s 

rule. 

2. How Was This Proposal Developed? 

a. Definition of an LRAA. The primary 

objective of the LRAA is to reduce 

exposure to high DBP levels. For an 

LRAA, an annual average must be 

computed at each monitoring site. The 

RAA compliance basis of the 1979 

TTHM rule and the Stage 1 DBPR allows 

a system-wide annual average under 

which high DBP concentrations in one 

or more locations are averaged with, and

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49585

dampened by, lower concentrations 

elsewhere in the distribution system. 

Figure V–1 illustrates the difference in 

calculating compliance with the MCLs 

for TTHM between a Stage 1 DBPR 

RAA, and the proposed Stage 2 DBPR 

LRAA. 

BILLING CODE 6560–50–P

BILLING CODE 6560–50–P


EP18AU03.008</GPH>
49586 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

b. Consideration of regulatory 

alternatives. This section will discuss 

EPA’s and the Stage 2 M-DBP Advisory 

Committee’s decision-making process as 

an array of alternative MCL strategies 

were considered. EPA believes that the 

MCL alternative proposed today (MCLs 

of 0.080 mg/L TTHM, 0.060 mg/L HAA5 

as LRAAs) is supported by the best 

available research, data, and analysis. 

The science related to cancer and 

reproductive and developmental health 

effects that may be associated with 

DBPs, in conjunction with occurrence 

data that show that a significant number 

of high DBP levels occur under current 

regulatory scenarios, justify a change in 

regulation. EPA believes that this 

proposal achieves an appropriate 

balance between the available science 

and the uncertainties. EPA believes that 

regulatory action is necessary and 

prudent in the interest of further public 

health protection and that the LRAA 

alternative in combination with the 

IDSE is a balanced and reasonable 

approach. Although it will not remove 

all DBP peaks (individual samples with 

values greater than the MCL), this 

proposed regulation will ensure that 

DBP exposures across a system’s 

distribution system are further reduced, 

are more equitable, and may reduce 

cancer and reproductive and 

developmental risk. 

The Advisory Committee discussions 

primarily focused on the relative 

magnitude of exposure reduction versus 

the expected impact on the water 

industry and its customers. Initially, 

this analysis compared expected 

reductions in DBP levels and 

predictions of treatment technology 

changes associated with a wide variety 

of Stage 2 DBPR MCL alternatives. 

After initial discussions, EPA and the 

Advisory Committee primarily focused 

on four types of alternative rule 

scenarios.

Preferred Alternative.—MCLs of 0.080 

mg/L TTHM and 0.060 mg/L HAA5 as 

LRAAs. Bromate MCL of 0.010 mg/L. 

Alternative 1.—MCLs of 0.080 mg/L 

TTHM and 0.060 mg/L HAA5 as 

LRAAs. Bromate MCL of 0.005 mg/L. 

Alternative 2.—MCLs of 0.080 mg/L 

TTHM and 0.060 mg/L HAA5 as 

individual sample maximums (i.e., no 

single sample could exceed the MCL). 

Bromate MCL of 0.010 mg/L. 

Alternative 3.—MCLs of 0.040 mg/L 

TTHM and 0.030 mg/L HAA5 as 

RAAs. Bromate MCL of 0.010 mg/L.

EPA and the Advisory Committee, 

with assistance from the Technical 

Workgroup, conducted an in-depth 

analysis of these regulatory alternatives. 

In the process of evaluating alternatives, 

EPA and the Advisory Committee 

reviewed vast quantities of data and 

many analyses that addressed health 

effects, DBP occurrence, predicted 

reductions in DBP levels, predicted 

technology changes, and capital, annual, 

and household costs. Details of the 

compliance, occurrence, and cost 

forecasts for the four alternative rule 

scenarios are described in the Stage 2 

DBPR Economic Analysis (EA) (USEPA 

2003i) and the Stage 2 DBPR Occurrence 

Document (USEPA 2003o). 

In the end, the Advisory Committee 

recommended the Preferred Alternative 

in combination with the IDSE which 

they believed would reduce exposure to 

high levels of DBPs. Today, EPA is 

proposing the Preferred Alternative in 

combination with the IDSE. 

The only difference between the 

Preferred Alternative and Alternative 1 

is the bromate MCL. The Advisory 

Committee’s recommendation to 

maintain the Stage 1 DBPR bromate 

MCL of 0.010 mg/L is discussed in 

section V.G. of today’s proposal. 

Alternatives 2 and 3 are significantly 

more stringent than the Stage 1 DBPR 

with respect to the TTHM and HAA5 

requirements. Alternative 2 would 

require that all samples be below the 

MCL. Because DBP occurrence is 

variable across the distribution system 

and over time (as discussed in section 

IV), systems would have to base their 

disinfectant and treatment strategies on 

controlling their highest DBP 

occurrence levels. Alternative 3 

maintains the Stage 1 DBPR RAA 

compliance calculation, but reduces the 

Stage 1 DBPR MCLs by 50 percent. Both 

alternatives 2 and 3 would cause 

significant changes in treatment for a 

large number of systems. The estimated 

costs for Alternatives 2 and 3 are 

approximately an order of magnitude 

above the costs for the Preferred 

Alternative (see section VII.B.). 

Consistent with this greater stringency 

of alternatives 2 and 3, the predicted 

DBP reductions and the resulting health 

benefits for them are greater than those 

predicted for the Preferred Alternative. 

Although all members of the Advisory 

Committee believed that the science 

showing reproductive and 

developmental health effects that have 

been associated with DBPs was 

sufficient to cause concern and warrant 

regulatory action, the Advisory 

Committee did not believe that the 

association was certain enough to justify 

the substantial change in treatment 

technologies that would be required to 

meet these alternatives. Thus, the 

Advisory Committee rejected 

Alternatives 2 and 3. 

c. Basis for the LRAA. This section 

discusses the data and information EPA 

used to determine that the LRAA is an 

appropriate compliance strategy for 

today’s proposed rule. EPA has chosen 

compliance based on an LRAA due to 

concerns about levels of DBPs above the 

MCL in some portions of the 

distribution system. The LRAA standard 

will eliminate system-wide averaging. 

The individuals served in areas of the 

distribution system with above average 

DBP occurrence levels masked by 

averaging under an RAA are not 

receiving the same level of health 

protection. Although an LRAA standard 

still allows averaging at a single location 

over an annual period, EPA believes 

that changing the basis of compliance 

from an RAA to an LRAA will result in 

decreased exposure to above average 

DBP levels (see section VII.A. for 

predictions of DBP reductions under the 

LRAA MCLs). This conclusion is based 

on three considerations:

(1) There is considerable evidence 

that under the current RAA MCL 

compliance monitoring requirements a 

small but significant proportion of 

monitoring locations experience high 

DBP levels. As summarized in section 

IV of this preamble, 14 and 21% of 

Information Collection Rule systems 

currently meeting the Stage 1 DBPR 

RAA MCLs had TTHM and HAA5 single 

sample concentrations greater than the 

Stage 1 MCLs and ranged up to 140 μg/

L and 130 μg/L respectively (Figures IV–

1 and IV–2), though most of these 

exceedences were below 100 μg/L. 

(2) In some situations, the populations 

served by certain portions of the 

distribution system consistently receive 

water that exceeds the MCL even though 

the system is in compliance. As 

discussed in section IV of this preamble, 

some Information Collection Rule 

systems meeting the Stage 1 DBPR RAA 

MCLs had monitoring locations that 

exceeded 0.080 mg/L TTHM and/or 

0.060 mg/L HAA5 as an annual average 

(i.e., as LRAAs) by up to 25% (Figures 

IV–3 and IV–4). Five percent of plants 

that achieved compliance with the Stage 

1 TTHM MCL of 0.080 mg/L based on 

an RAA had a particular sampling 

location that exceeded 0.080 mg/L as an 

LRAA (Figure IV–3). Figure IV–4 shows 

similar results based on Information 

Collection Rule HAA5 data. Three 

percent of plants that met the Stage 1 

HAA5 MCL of 0.060 mg/L as an RAA 

had a sampling location that exceeded 

0.060 mg/L as an LRAA. Customers 

served at these locations consistently 

received water with TTHM and/or 

HAA5 concentrations higher than the 

system-wide MCL.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49587

(3) Compliance based on an LRAA 

will remove the opportunity for systems 

to average out samples from high and 

low quality water sources. Some 

systems are able to comply with an RAA 

MCL even if they have a plant with a 

poor quality water source (that thus 

produces high concentrations of DBPs) 

because they have another plant that has 

a better quality water source (and thus 

lower concentrations of DBPs). 

Individuals served by the plant with the 

poor quality source will usually have 

higher DBP exposure than individuals 

served by the other plant. 

d. Basis for phasing LRAA 

compliance. EPA believes that a phased 

approach for LRAA implementation will 

facilitate transition to the new 

compliance requirements. Stage 2A of 

this proposed rule does not require 

systems to conduct any additional 

monitoring. They will continue to 

monitor at Stage 1 DBPR locations. 

Because the LRAA calculation is the 

same as the RAA calculation if there is 

only one site, Stage 2A compliance only 

applies to systems that monitor at more 

than one site and will only affect 

medium and large surface water systems 

(serving at least 10,000 people) or 

systems with multiple plants. Thus, the 

majority of ground water systems, small 

surface water systems, and some 

consecutive systems are not affected by 

the proposed Stage 2A requirements. 

e. TTHM and HAA5 as Indicators. In 

part, both the TTHM and HAA5 classes 

are regulated because they occur at high 

levels and represent chlorination 

byproducts that are produced from 

source waters with a wide range of 

water quality. The combination of 

TTHM and HAA5 represent a wide 

variety of compounds resulting from 

bromine substitution and chlorine 

substitution reactions (i.e., bromoform 

has 3 bromines, TCAA has 3 chlorines, 

BDCM has one bromine and two 

chlorines, etc). EPA believes that the 

TTHM and HAA5 classes serve as an 

indicator for unidentified and 

unregulated DBPs. EPA believes that 

controlling the occurrence levels of 

TTHM and HAA5 will control the levels 

of all chlorination DBPs to some extent. 

3. Request for Comment 

EPA requests comment on the 

alternative MCL strategies that were 

considered by the Advisory Committee 

and the determination to propose the 

Preferred Alternative in combination 

with the IDSE as the preferred 

regulatory strategy. EPA also requests 

comment on whether the proposed 

approach will reduce peak DBP levels. 

EPA requests comment on the phased 

MCL strategy and whether or not it will 

facilitate compliance with the LRAA. 

EPA also requests comment on the Stage 

2A MCLs of 0.120 mg/L TTHM and 

0.100 mg/L HAA5 as LRAAs and on the 

long-term MCLs of 0.080 mg/L TTHM 

and 0.060 mg/L HAA5 as LRAAs. 

E. Requirements for Peak TTHM and 

HAA5 Levels 

1. What Is EPA Proposing Today? 

Today, EPA is proposing that, 

concurrent with Stage 2B, systems must 

specifically document occurrences of 

peak DBP levels, termed significant 

excursions. In support of this provision, 

EPA is proposing that States, as a 

special primacy condition, develop 

criteria for determining whether a 

system has a significant excursion. EPA 

has developed draft guidance for 

systems and States on how systems may 

determine whether they have significant 

excursions. EPA is also proposing that 

a system that has a significant excursion 

must: (1) Evaluate distribution system 

operational practices to identify 

opportunities to reduce DBP levels 

(such as tank management to reduce 

residence time and flushing programs to 

reduce disinfectant demand), (2) 

prepare a written report of the 

evaluation, and (3) no later than the 

next sanitary survey, review the 

evaluation with their State. This review 

will take place under the sanitary 

survey components calling for the State 

to review monitoring, reporting, and 

data verification and system 

management and operation. 

2. How Was This Proposal Developed? 

Because individual measurements 

from a location are averaged over a fourquarter period to determine compliance, 

there may be occurrence levels that 

exceed the MCL even when a system is 

in compliance with an LRAA MCL. EPA 

and the Advisory Committee were 

concerned about these exposures to 

peak levels of DBPs and the possible 

risk they might pose. This concern was 

clearly reflected in the Agreement in 

Principle, which states, 

‘‘Recognizing that significant 

excursions of DBP levels will sometimes 

occur, even when systems are in full 

compliance with the enforceable MCL, 

public water systems that have 

significant excursions during peak 

periods are to refer to EPA guidance on 

how to conduct peak excursion 

evaluations, and how to reduce such 

peaks. Such excursions will be reviewed 

as part of the sanitary survey process. 

EPA guidance on DBP level excursions 

will be issued prior to promulgation of 

the final rule and will be developed in 

consultation with stakeholders.’’

In evaluating this recommendation, 

EPA believes that the Advisory 

Committee’s intent was clear with 

regard to the need for guidance on how 

to evaluate and reduce significant 

excursions. However, the Agreement is 

less clear on how, and where, to define 

what constitutes a significant excursion, 

and how to define the scope of the 

evaluation. EPA draft guidance 

recommends several approaches for 

determining whether significant 

excursions have occurred. While today’s 

proposal requires an evaluation only of 

distribution system operational 

practices, EPA believes that many 

systems would benefit from a broader 

evaluation that includes treatment plant 

and other system operations. 

EPA recognizes that different 

stakeholders have different points of 

view on whether specific criteria that 

initiate the evaluation of significant 

excursions should be included in the 

rule or in guidance. EPA also recognizes 

that different stakeholders may have 

different perspectives on how to 

identify a significant excursion. For this 

proposal, EPA has prepared draft 

guidance for systems and States on how 

to (1) determine whether a significant 

excursion has occurred, using several 

different options, (2) conduct significant 

excursion evaluations, and (3) reduce 

significant excursion occurrence.

3. Request for Comment 

EPA requests comment on the 

proposed approach for addressing 

significant excursions and on the draft 

guidance. Is a special primacy condition 

the appropriate means for allowing 

flexibility in identifying significant 

excursions while ensuring that such 

evaluations occur? Is the sanitary survey 

the appropriate mechanism for 

reviewing significant excursion data 

with the State? Should a system be 

required to take corrective action when 

significant excursions occur? Should the 

required scope of the evaluation be 

expanded beyond distribution system 

operations? 

EPA also requests comment on 

whether specific criteria that initiate the 

evaluation of significant excursions 

should be included in the rule or in 

guidance. EPA requests comment on 

how to identify significant excursions 

(regardless of whether the criteria are in 

the rule or in guidance). For example, 

should the significant excursion be 

based on an individual measurement, 

e.g., any measurement being 25 or 50% 

over either the TTHM or HAA5 MCLs? 

Alternatively, should the determination 

of a significant excursion be based on a 

certain level of variability among 

multiple measurements? For example,

49588 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

should the significant excursion be 

based on the standard deviation of the 

LRAA exceeding specific numerical 

values for either TTHM (e.g., 0.020 mg/

l) or HAA5 (e.g., 0.015 mg/L)? Or should 

the excursion be based on a relative 

measure of variability (e.g., a relative 

standard deviation exceeding 25% or 

50%) with the condition of a threshold 

average concentration also being 

exceeded (e.g., an LRAA needing to be 

at least 0.040 mg/l for TTHM or 0.030 

mg/l for HAA5)? EPA requests comment 

on the above approaches or alternative 

approaches for determining whether a 

significant excursion has occurred. EPA 

also requests comment on whether 

different approaches may be appropriate 

for large and small systems. 

F. BAT for TTHM and HAA5 

1. What Is EPA Proposing Today? 

Today, EPA is proposing that the best 

available technology (BAT) for the 

TTHM and HAA5 LRAA MCLs (0.080 

mg/L and 0.060 mg/L respectively) be 

one of the three following technologies: 

(1) GAC adsorbers with at least 10 

minutes of empty bed contact time and 

an annual average reactivation/

replacement frequency no greater than 

120 days, plus enhanced coagulation or 

enhanced softening. 

(2) GAC adsorbers with at least 20 

minutes of empty bed contact time and 

an annual average reactivation/

replacement frequency no greater than 

240 days. 

(3) Nanofiltration (NF) using a 

membrane with a molecular weight cut 

off of 1000 Daltons or less (or 

demonstrated to reject at least 80% of 

the influent TOC concentration under 

typical operating conditions). 

EPA is proposing a different BAT for 

consecutive systems than for wholesale 

systems to meet the TTHM and HAA5 

LRAA MCLs. The proposed consecutive 

system BAT is chloramination with 

management of hydraulic flow and 

storage to minimize residence time in 

the distribution system. 

2. How Was This Proposal Developed? 

a. Basis for the BAT. The Safe 

Drinking Water Act directs EPA to 

specify BAT for use in achieving 

compliance with the MCL. Systems 

unable to meet the MCL after 

application of BAT can get a variance 

(see section V.L. for a discussion of 

variances). Systems are not required to 

use BAT in order to comply with the 

MCL. They can use other technologies 

as long as they meet all drinking water 

standards and are approved by the State. 

EPA examined BAT using two 

different methods: (1) EPA analyzed 

data from the Information Collection 

Rule treatment studies and (2) EPA used 

the Surface Water Analytical Tool 

(SWAT), a model developed to compare 

alternative regulatory strategies. Both 

analyses support the BAT options 

proposed today. The results of each 

analyses are presented in the following 

two sections. 

i. BAT analysis using the Information 

Collection Rule treatment studies. EPA 

analyzed data from the Information 

Collection Rule treatment studies 

(Information Collection Rule Treatment 

Study Database CD–ROM, Version 1.0, 

USEPA 2000m; Hooper and Allgeier 

2002). The treatment studies were 

designed to evaluate the technical 

feasibility of using GAC and NF to 

remove DBP precursors prior to the 

addition of chlorine-based disinfectants. 

Systems were required to conduct an 

Information Collection Rule treatment 

study based on TOC levels in the source 

or finished water. Specifically, surface 

water plants with annual average source 

water TOC concentrations greater than 4 

mg/L and ground water plants with 

annual average finished water TOC 

concentrations greater than 2 mg/L were 

required to conduct treatment studies. 

Thus, the plants required to conduct 

treatment studies generally had waters 

with organic DBP precursor levels that 

were significantly higher than the 

Information Collection Rule national 

plant medians of 2.7 mg/L for source 

water at surface water plants and 0.2 

mg/L for finished water at ground water 

plants (USEPA 2003o). 

Plants that conducted GAC studies 

typically evaluated performance at two 

empty bed contact times, 10 and 20 

minutes, over a wide range of 

operational run times to evaluate the 

variable nature of TOC removal by GAC. 

This allowed GAC performance to be 

assessed with respect to empty bed 

contact time as well as reactivation/

replacement frequency. Plants that 

conducted membrane treatment studies 

evaluated one or two nanofiltration 

membranes with molecular weight 

cutoffs less than 1000 Daltons. 

Regardless of the technology evaluated, 

all treatment studies evaluated DBP 

formation in the effluent from the 

advanced process under simulated 

distribution system conditions 

representative of the average residence 

time and using free chlorine as the 

primary and residual disinfectant. (For 

more information on the Information 

Collection Rule treatment study 

requirements and testing protocols, see 

USEPA 1996 a and b.) 

Based on the treatment study results, 

GAC is effective for controlling DBP 

formation for waters with influent TOC 

concentrations below approximately 6 

mg/L (based on the Information 

Collection Rule and NRWA data, over 

90 percent of plants have average 

influent TOC levels below 6 mg/L 

(USEPA 2003o)). Of the plants that 

conducted an Information Collection 

Rule GAC treatment study, 

approximately 70% of the surface water 

plants studies could meet the 0.080 mg/

L TTHM and 0.060 mg/L HAA5 MCLs, 

with a 20% safety factor (i.e., 0.064 mg/

L and 0.048 mg/L, respectively) using 

GAC with 10 minutes of empty bed 

contact time and a 120 day reactivation 

frequency, and 78% of the plants could 

meet the MCLs with a 20% safety factor 

using GAC with 20 minutes of empty 

bed contact time and a 240 day 

reactivation frequency. As discussed 

previously, the treatment studies were 

conducted at plants with poorer water 

quality than the national average. 

Therefore, EPA believes that much 

higher percentages of plants nationwide 

could meet the MCLs with the proposed 

GAC BATs. 

Among plants using GAC, larger 

systems would likely realize an 

economic benefit from on-site 

reactivation, which could allow them to 

use smaller, 10-minute empty bed 

contact time contactors with more 

frequent reactivation (i.e., 120 days or 

less). Most small systems would not 

find it economically advantageous to 

install on-site carbon reactivation 

facilities, and thus would opt for larger, 

20-minute empty bed contact time 

contactors, with less frequent carbon 

replacement (i.e., 240 days or less).

The proposed reactivation/

replacement interval for the 20 minute 

contactor (i.e., 240 days) is double the 

reactivation/replacement interval for 10 

minute contactor (i.e., 120 days). This is 

based on the assumption of a linear 

relationship between empty bed contact 

time and the reactivation interval (e.g., 

a doubling of the empty bed contact 

time will result in a doubling of the 

reactivation interval). The data from the 

Information Collection Rule treatment 

studies indicates that this linear 

relationship may not always hold and 

that doubling the empty bed contact 

time generally results in more than a 

doubling of the reactivation interval. 

While there may be some operational 

advantage in using larger empty bed 

contact times, the larger contactors will 

result in additional capital 

expenditures. Furthermore, the 

economic optimization of a GAC 

process must also consider the number 

of smaller contactors in parallel, since it 

may be advantageous to operate a larger 

number of smaller contactors in parallel, 

allowing each individual contactor to be

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49589

operated for a longer period of time. 

Based on these considerations, and the 

analysis of subject matter experts, it was 

concluded that the proposed 

combination of GAC empty bed contact 

times and reactivation/replacement 

intervals were reasonable for BAT. 

The Information Collection Rule 

treatment study results also 

demonstrated that nanofiltration was 

the better DBP control technology for 

ground water sources with high TOC 

concentrations (i.e., above 

approximately 6 mg/L). The results of 

the membrane treatment studies showed 

that all ground water plants could meet 

the 0.080 mg/L TTHM and 0.060 mg/L 

HAA5 MCLs, with a 20% safety factor 

(i.e., 0.064 mg/L and 0.048 mg/L, 

respectively) at the average distribution 

system residence time using 

nanofiltration. Nanofiltration would be 

less expensive than GAC for high TOC 

ground waters, which generally require 

minimal pretreatment prior to the 

membrane process. Also, nanofiltration 

is an accepted technology for treatment 

of high TOC ground waters in Florida 

and parts of the Southwest, areas of the 

country with elevated TOC levels in 

ground waters. 

ii. BAT analysis using the SWAT. The 

second method that EPA used to 

examine alternatives for BAT was the 

SWAT model that was developed to 

compare alternative regulatory 

strategies. EPA modeled the following 

BAT options: enhanced coagulation/

softening with chlorine (the Stage 1 

DBPR BAT); enhanced coagulation/

softening with chlorine and no 

predisinfection; enhanced coagulation 

and GAC10; enhanced coagulation and 

GAC20; and enhanced coagulation and 

chloramines. Enhanced coagulation/

softening is required under the Stage 1 

DBPR at subpart H conventional 

filtration plants. In the model, GAC10 

was defined as granular activated 

carbon with an empty bed contact time 

of 10 minutes and a reactivation or 

replacement interval of 90 days or 

longer. GAC20 was defined as granular 

activated carbon with an empty bed 

contact time of 20 minutes and a 

reactivation or replacement interval of 

90 days or longer. EPA assumed that 

systems would be operating to achieve 

both the Stage 2B MCLs of 0.080 mg/L 

TTHM and 0.060 mg/L HAA5 as an 

LRAA and the SWTR removal and 

inactivation requirements of 3-log for 

Giardia and 4-log for viruses. EPA also 

evaluated the BAT options under the 

assumption that plants operate to 

achieve DBP levels 20% below the MCL 

(safety factor). These assumptions along 

with other inputs for the SWAT runs are 

consistent with those used in the 

Economic Analysis of today’s proposed 

rule (USEPA 2003i). 

The compliance percentages 

forecasted by the SWAT model are 

indicated in Table V–1. EPA estimates 

that more than 97% of large systems 

will be able to achieve the Stage 2B 

MCLs regardless of post-disinfection 

choice if they were to apply one of the 

proposed GAC BATs, i.e., enhanced 

coagulation (EC) and GAC10 (Seidel 

Memo, 2001). As shown in the Stage 2 

DBPR Occurrence document (USEPA 

2003o), the source water quality (e.g., 

DBP precursor levels) in medium and 

small systems is expected to be 

comparable to or better than that for the 

large systems. Based on the large system 

estimate, EPA believes it is conservative 

to assume that at least 90% of medium 

and small systems will be able to 

achieve the Stage 2B MCLs if they were 

to apply one of the proposed GAC 

BATs. EPA assumes that small systems 

may adopt GAC20 in a replacement 

mode (with replacement every 240 days) 

over GAC10 because it may not be 

economically feasible for some small 

systems to install and operate an on-site 

GAC reactivation facility. Moreover, 

some small systems may find 

nanofiltration cheaper than the GAC20 

in a replacement mode if their specific 

geographic locations cause a relatively 

high cost for routine GAC shipment.

TABLE V–1.—SWAT MODEL PREDICTIONS OF PERCENT OF LARGE PLANTS IN COMPLIANCE WITH TTHM AND HAA5 

STAGE 2B MCLS AFTER APPLICATION OF SPECIFIED TREATMENT TECHNOLOGIES

Technology *

Compliance with 0.080 mg/L (TTHM)/0.060 mg/L 

(HAA5) LRAAs 

Compliance with 0.064 mg/L (TTHM)/0.048 mg/L 

(HAA5) LRAAs (MCLs with 20% safety factor) 

Residual disinfectant 

All systems 

Residual disinfectant 

All systems 

Chlorine Chloramine Chlorine Chloramine 

Enhanced Coagulation (EC) ........ 73.5 76.9 74.8 57.2 65.4 60.4 

EC (no predisinfection) ................ 73.4 88.0 78.4 44.1 62.7 50.5 

EC & GAC10 ................................ 100 97.1 99.1 100 95.7 98.6 

EC & GAC20 ................................ 100 100 100 100 100 100 

EC & All Chloramines .................. NA 83.9 NA NA 73.6 NA 

*Enhanced coagulation/softening is required under the Stage 1 DBPR for conventional plants. 

b. Basis for the Consecutive System 

BAT. EPA believes that the best 

compliance strategy for consecutive 

systems is to collaborate with 

wholesalers on the water quality they 

need. For consecutive systems that are 

having difficulty meeting the MCLs, 

EPA is proposing a BAT of 

chloramination with management of 

hydraulic flow and storage to minimize 

residence time in the distribution 

system. EPA is proposing a different 

BAT than for wholesale systems because 

a consecutive system’s source water has 

already been disinfected and contains 

DBPs that cannot be effectively removed 

or controlled with the BATs proposed 

for wholesale systems. EPA believes the 

proposed consecutive system BAT is an 

effective means for consecutive systems 

to meet the MCLs. 

Chloramination has been used for 

residual disinfection for many years to 

minimize the formation of chlorination 

DBPs, including TTHM and HAA5 

(Stage 2 Technology and Cost 

Document, USEPA 2003k). The BAT 

provision to manage hydraulic flow and 

minimize residence time in the 

distribution system is to facilitate the 

maintenance of the chloramine residual 

and minimize the likelihood for 

nitrification. Nitrification, the process 

by which microbes convert free 

ammonia to nitrate and nitrite, is a 

concern for systems using chloramines. 

Nitrification, however, can be controlled 

with appropriate chlorine to ammonia 

ratios, increasing flow in low demand 

areas, and increasing storage tank 

turnover. EPA proposes that systems 

implementing the consecutive system 

BAT must do the following: (1) 

Maintain a chloramine residual 

throughout the distribution system, (2) 

develop and submit a plan that 

indicates actions that will be taken to 

minimize the residence time of water

49590 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

within the distribution system, (3) have 

the plan approved by the Primacy 

Agency, and (4) implement the plan as 

approved by the Primacy Agency. 

Minimum components of the 

management plan would include 

periodic scheduled flushing of all dead 

end pipes and storage vessels through 

which water is delivered to customers, 

and hydraulic flow control procedures 

that routinely circulate water in all 

storage vessels within the distribution 

system. 

EPA believes that the BATs proposed 

for wholesale systems are not 

appropriate for consecutive systems 

because each of these BATs, when 

applied to water with DBPs, raises other 

concerns. GAC is not cost-effective for 

removing DBPs. In addition, dioxin, a 

carcinogen, may be formed during GAC 

regeneration if GAC has been used to 

adsorb chlorinated DBPs. Nanofiltration 

is only moderately effective at removing 

THMs or HAAs if membranes that have 

a very low molecular weight cutoff and 

very high cost of operation are 

employed. Therefore, GAC and 

nanofiltration are not appropriate BATs 

for consecutive systems. 

3. Request for Comment 

EPA requests comment on the 

proposed BATs including the BAT for 

consecutive systems. 

G. MCL, BAT, and Monitoring for 

Bromate 

1. What Is EPA Proposing Today? 

EPA is proposing today that the MCL 

for bromate for systems using ozone 

remain at 0.010 mg/L as an RAA for 

samples taken at the entrance to the 

distribution system as established by the 

Stage 1 DBPR and as provided for under 

the risk-balancing provisions of section 

1412(b)(5) of the SDWA. EPA’s proposal 

is consistent with the recommendation 

of the Stage 2 M–DBP Advisory 

Committee, which considered the 

potential that reducing the bromate 

MCL could both increase the 

concentration of other DBPs in the 

drinking water and interfere with the 

efficacy of microbial pathogen 

inactivation. In addition, as required by 

the SDWA and as recommended by the 

Advisory Committee, EPA will review 

the bromate MCL as part of the 6-year 

review process and determine whether 

the MCL should remain at 0.010 mg/L 

or be reduced to a lower level. As a part 

of that review, EPA will consider the 

increased utilization of alternative 

technologies, such as UV, and whether 

the risk/risk concerns reflected in 

today’s proposal remain valid.

Because EPA is not revising the Stage 

1 DBPR bromate MCL, EPA is not 

proposing a revised BAT for bromate. 

The Stage 1 DBPR BAT for bromate is 

defined as control of ozone treatment 

processes to reduce production of 

bromate. EPA also determined that it 

was not necessary to regulate bromate in 

non-ozone systems that use 

hypochlorite. 

Finally, EPA is proposing to modify 

the criterion for a system that uses 

ozone (and therefore must monitor for 

bromate) to qualify for reduced bromate 

monitoring from one sample per ozone 

plant per month to one sample per plant 

per quarter. 

2. How Was This Proposal Developed? 

a. Bromate MCL. Bromate is a 

principal byproduct from ozonation of 

bromide-containing source waters. As 

described in more detail later, making 

the bromate MCL more stringent has the 

potential to decrease current levels of 

microbial protection, impair the ability 

of systems to control resistant pathogens 

like Cryptosporidium, and increase 

levels of DBPs from other disinfectants 

that may be used instead of ozone. 

EPA estimates that the 1 in 10,000 

excess lifetime cancer risk level for 

bromate is 0.005 mg/L. EPA proposed 

and ultimately finalized an MCL of 

0.010 mg/L in the Stage 1 DBPR, 

primarily because available analytical 

detection methods for bromate could 

only reliably measure to 0.01 mg/L 

(USEPA 1994b). Analytical methods for 

bromate are now available to quantify 

bromate concentrations as low as 0.001 

mg/L. Due to the availability of lower 

detection methods for bromate, as part 

of the Stage 2 M–DBP Advisory 

Committee deliberations, EPA 

considered revising the MCL to 0.005 

mg/L or lower. 

As a disinfectant, ozone is highly 

effective against a broad range of 

microbial pathogens including bacteria, 

viruses, and protozoa. Moreover, ozone 

is one of the few disinfectants available 

in water treatment that is capable of 

inactivating Cryptosporidium, a 

protozoan which can cause severe 

intestinal disorders and can be deadly to 

those with compromised immune 

systems. The oxidizing properties of 

ozone are also valuable for treatment 

objectives like control of tastes and 

odors and removal of iron and 

manganese. In contrast, chlorine, the 

most common disinfectant and oxidant 

in water treatment, is substantially less 

effective for controlling 

Cryptosporidium. Chlorine dioxide, 

while capable of providing low levels of 

inactivation for Cryptosporidium,

typically cannot be used at high doses 

without violating the MCL for chlorite, 

a byproduct of chlorine dioxide. UV 

light is highly effective against 

Cryptosporidium and Giardia and most 

viruses, but has not been used 

extensively to treat drinking water in 

the United States. 

As of early 2000, there were 332 

plants of various sizes using ozone 

(Overbeck 2000) and 58 plants that were 

planning to install ozonation (Rice 

2000—personal communication: email 

7/14/2000). A significant percent of 

current ozone plants use ozone for some 

portion of their disinfection objective 

(Rice, 2000—personal communication: 

email 7/14/2000). An ozone system that 

could not meet a 0.005 mg/L bromate 

MCL would have three primary options: 

decrease the ozone dose; switch to a 

different disinfectant; or install an 

advanced filtration process such as 

membranes, sometimes in combination 

with the first two options. Of these three 

options, the third is likely effective but 

very expensive, while the first two 

create the risk either of reducing 

microbial protection for a wide range of 

microbial pathogens, or of increasing 

formation of DBPs other than bromate. 

In an attempt to achieve a lower level 

of bromate, some systems might be 

driven to reduce the applied ozone dose 

to the minimum necessary for regulatory 

compliance or switch to other treatment 

processes. Many systems currently 

achieve more disinfection than is 

required by the SWTR and if a system 

were to simply lower the ozone dose, 

protection from pathogens may be 

compromised. In addition, since 

inactivation of Cryptosporidium

requires much higher ozone doses than 

Giardia inactivation, systems cannot 

achieve Cryptosporidium inactivation 

with low ozone doses. 

If a system were to lower the ozone 

dose and supplement with an additional 

disinfectant, or switch entirely to a 

different disinfectant, the system may 

not achieve the same level of microbial 

protection as is afforded by ozonation. 

Also, other potentially harmful 

byproducts from the different 

disinfectant would be produced. 

During the Stage 2 M–DBP Advisory 

Committee discussions, the TWG 

evaluated the impact of reducing the 

bromate MCL from 0.010 mg/L to 0.005 

mg/L as an annual average. The TWG 

concluded that many systems currently 

using ozone or predicted to install 

ozone to inactivate microbial pathogens 

would have significant difficulty 

maintaining bromate levels at or below 

0.005 mg/L. In the Information 

Collection Rule survey of systems 

serving greater than 100,000 people, all 

of the ozone plants had annual average

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49591

bromate concentrations below the 0.010 

mg/L level (USEPA 2003o). However, 

approximately 20% of these ozone 

plants did not meet the 0.005 mg/L 

level. Using the assumption that 

systems operate their plants using a 

safety margin of 20% below the MCL, 

about 30% of ozone plants did not 

reliably attain this level (0.004 mg/L). 

During the Information Collection Rule, 

for the first half of 1998, much of the 

U.S. was wetter than normal (NOAA 

1998). This hydrogeological condition 

often leads to lower than normal 

bromide concentrations due to dilution 

by higher water flows. In the second 

half of 1998, California continued to 

experience El Nino rains (40% of 

Information Collection Rule ozone 

plants were located in California) but 

many other areas of the country such as 

Texas and Florida experienced a 

drought. The percentage of ozone 

systems unable to achieve 0.005 mg/L 

bromate would likely increase during 

years in which bromide concentrations 

in California were elevated as 

consequence of drought. 

The ability of systems to use ozone to 

meet Cryptosporidium treatment 

requirements proposed under the 

LT2ESWTR would be diminished if the 

bromate MCL was decreased from 0.010 

to 0.005 mg/L. The proposed 

LT2ESWTR will require a subset of 

systems, based on source water 

pathogen levels, to provide from 1.0 to 

2.5 logs of additional treatment for 

Cryptosporidium. Ozone doses required 

to inactivate Cryptosporidium are 

substantially greater than those required 

for Giardia and viruses. To assess the 

potential impact of a lower bromate 

MCL on the ability of systems to treat 

for Cryptosporidium, the TWG 

estimated the percentage of treatment 

plants that could use ozone to inactivate 

from 0.5 to 2.5 log of Cryptosporidium

without exceeding a bromate MCL of 

either 0.005 or 0.010 mg/L (USEPA 

2003i). These estimations were based on 

analyses of Information Collection Rule 

source water quality data, coupled with 

projected ozone dose requirements for 

Cryptosporidium. This analysis suggests 

that 88% of systems could use ozone to 

achieve 1 log of Cryptosporidium

inactivation and 47% could inactivate 2 

log while complying with a bromate 

MCL of 0.010 mg/L. With the bromate 

MCL reduced to 0.005 mg/L, though, 

these estimates drop to 67% of systems 

able to inactivate 1 log of 

Cryptosporidium with ozone and only 

14% able to inactivate 2 log. The 

number of plants predicted to be able to 

treat for Cryptosporidium with ozone 

and meet a 0.005 mg/L standard was 

further reduced when periods of higher 

bromide levels, similar to drought 

conditions, were modeled. This trend is 

further exacerbated since the proposed 

LT2ESWTR would require more 

stringent ozone operating conditions 

(such as higher ozone doses and longer 

contact times) than under current 

surface water treatment requirements for 

the subset of plants with higher 

Cryptosporidium concentrations in their 

source water and would thus result in 

higher bromate formation than assumed 

by the TWG. Thus, as systems are 

required to meet more stringent 

inactivation requirements, a large 

number of systems would be forced to 

select treatment processes other than 

ozone if the bromate standard were 

lowered to 0.005 mg/L.

The Stage 2 M–DBP Advisory 

Committee considered that reducing the 

bromate MCL to 0.005 mg/L could both 

increase the concentration of other DBPs 

in the drinking water and interfere with 

the efficacy of microbial pathogen 

inactivation. Therefore, the Advisory 

Committee recommended, for purposes 

of the Stage 2 DBPR, that the bromate 

MCL remain at 0.010 mg/L. EPA will 

review the bromate MCL as part of the 

ongoing 6-year review process and 

determine whether the MCL should 

remain at 0.010 mg/L or be reduced to 

a lower concentration based on new 

information. 

Today, EPA is proposing to leave the 

bromate MCL at 0.010 mg/L, consistent 

with the Advisory Committee’s 

recommendation. EPA believes that this 

is a prudent step at this time, in order 

to preserve microbial protection. EPA 

will continue to analyze any new 

bromate health effects data as they 

become available. It is possible that EPA 

may determine that the bromate MCL 

should be decreased to 0.005 mg/L or 

lower in a future rulemaking. 

b. Bromate in hypochlorite solutions.

The Stage 2 M–DBP Advisory 

Committee also discussed the issue of 

hypochlorite solutions contaminated 

with bromate. This contamination can 

occur during the production of 

hypochlorite solutions from natural salt 

deposits. The range of bromate 

concentrations in hypochlorite stock 

solutions varies widely (Bolyard et al.

1992; Chlorine Institute 1999, 2000). 

Moreover, the bromate contained in the 

stock solution is diluted upon addition 

to the drinking water. From data on 

Information Collection Rule ozone 

systems that used hypochlorite versus 

those that used gaseous chlorine, the 

TWG estimated that hypochlorite 

solutions contributed an average of 

0.001 mg/L bromate. 

The Advisory Committee discussed 

these results and, since the bromate 

level resulting from hypochlorite 

solutions was small compared to the 

MCL, did not recommend regulating 

bromate at systems not using ozone 

(non-ozone systems). The Advisory 

Committee recognized that ozone 

systems also using hypochlorite will 

have to be careful about the quality of 

their stock solution. 

c. Criterion for reduced bromate 

monitoring. Because more sensitive 

bromate methods are now available, 

EPA is proposing a new criterion for 

reduced bromate monitoring. In the 

Stage 1 DBPR, EPA required ozone 

systems to demonstrate that source 

water bromide levels, as a running 

annual average, did not exceed 0.05 mg/

L. EPA elected to use bromide as a 

surrogate for bromate in determining 

eligibility for reduced monitoring 

because the available analytical method 

for bromate was not sensitive enough to 

quantify levels well below the bromate 

MCL of 0.010 mg/L. 

In section V.O., EPA is proposing 

several new analytical methods for 

bromate that are far more sensitive than 

the existing method. Since these 

methods can measure bromate to levels 

of 0.001 mg/L or lower, EPA is 

proposing to replace the criterion for 

reduced bromate monitoring (source 

water bromide running annual average 

not to exceed 0.05 mg/L) with a bromate 

running annual average not to exceed 

0.0025 mg/L. 

In the past, EPA has often set the 

criterion for reduced monitoring 

eligibility at 50% of the MCL, which 

would be 0.005 mg/L. However, as 

discussed before, EPA is proposing that 

the MCL for bromate remain at 0.010 

mg/L, a level that is higher than EPA’s 

usual excess cancer risk range of 10(-4) 

to 10(-6) at 2x10(-4) because of risk 

tradeoff considerations. EPA believes 

that the decision for reduced monitoring 

is separate from these risk tradeoff 

considerations. Risk tradeoff 

considerations influence the selection of 

the MCL, while reduced monitoring 

requirements are designed to ensure that 

the MCL, once established, is reliably 

and consistently achieved. Requiring a 

running annual average of 0.0025 mg/L 

for the reduced monitoring criterion 

allows greater confidence that the 

system is achieving the MCL and thus 

ensuring public health protection.

3. Request for Comment 

EPA requests comment on the 

decision to maintain the Stage 1 DBPR 

bromate BAT and MCL of 0.010 mg/L. 

EPA also requests comment on the 

decision not to require bromate

49592 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

monitoring at non-ozone systems that 

use hypochlorite. 

EPA requests comment on whether 

the criterion for reduced bromate 

monitoring should be set at a level other 

than 0.0025 mg/L, and a rationale for 

setting it at that level. 

H. Initial Distribution System 

Evaluation (IDSE) 

The IDSE is an important part of 

today’s proposed regulation that is 

intended to identify sample locations 

for Stage 2B compliance monitoring that 

represent distribution system sites with 

high DBP concentrations. 

1. What is EPA Proposing Today? 

EPA is proposing a requirement for 

systems to perform an Initial 

Distribution System Evaluation (IDSE). 

Systems will collect data on DBP levels 

throughout their distribution system, 

evaluate these data to determine which 

sampling locations are most 

representative of high DBP levels and 

compile this information into a report 

for submission to the primacy agency. 

a. Applicability. All community water 

systems, and large nontransient 

noncommunity water systems (those 

serving at least 10,000 people) that add 

a primary or residual disinfectant other 

than ultraviolet light, or that deliver 

water that has been treated with a 

primary or residual disinfectant other 

than ultraviolet light (i.e., consecutive 

systems) are required to conduct an 

IDSE under the proposed rule. The IDSE 

requirement for systems serving fewer 

than 500 people may be waived if the 

State determines that the monitoring 

site approved for Stage 1 DBPR 

compliance is sufficient to represent 

both high HAA5 and high TTHM 

concentrations. The State must submit 

criteria for this waiver determination to 

EPA as part of their primacy 

application. States may decide to waive 

the IDSE requirement for all systems 

serving fewer than 500 or some subset 

of all systems serving fewer than 500 if 

the State determines that it is 

appropriate. EPA is developing an IDSE 

Guidance Manual that will include 

guidance to States on situations for 

which a waiver would be appropriate 

(USEPA 2003j). 

b. Data collection. IDSEs are intended 

to help identify and select Stage 2B 

compliance monitoring sites that 

represent high concentrations of TTHMs 

and HAA5. To be able to identify these 

sites, systems and States must have 

monitoring data collected from 

throughout their distribution systems. 

Therefore, under today’s proposed rule, 

systems are required to collect 

monitoring data on the concentrations 

of these DBPs. There are three possible 

approaches by which a system can meet 

the IDSE requirement. 

i. Standard monitoring program. The 

standard monitoring program requires 

one year of monitoring on a specified 

schedule throughout the distribution 

system. The frequency and number of 

samples required under the standard 

monitoring program is determined by 

source water type, number of treatment 

plants, and system size (see section V.J. 

for a more detailed discussion of the 

specific monitoring requirements). Prior 

to commencing the standard monitoring 

program, systems must prepare a 

monitoring plan. EPA’s IDSE Guidance 

Manual will provide guidance on 

selecting monitoring sites and 

conducting the standard monitoring 

program (USEPA 2003j). As 

recommended by the Advisory 

Committee, EPA is proposing that the 

standard monitoring program results are 

not to be used for determining 

compliance with MCLs and that systems 

will not be required to report IDSE 

results in the Consumer Confidence 

Report. 

ii. System specific study. Under this 

approach, systems may choose to 

perform a system-specific study based 

on earlier monitoring studies or other 

data analysis in lieu of the standard 

monitoring program. These studies must 

provide equivalent or better information 

than the standard monitoring program 

for selecting sites that represent high 

TTHM and HAA5 levels. Examples of 

alternative studies are: (1) Recent TTHM 

and HAA5 monitoring data that 

encompass a wide range of sample sites 

representative of the distribution 

system, including those judged to 

represent high TTHM and HAA5 

concentrations and (2) hydraulic 

modeling studies that simulate water 

movement in the distribution system. 

Historical TTHM and HAA5 results 

submitted by systems must have been 

generated by certified laboratories and 

must include the system’s most recent 

data. Treatment plant and distribution 

system characteristics at the time of 

historical data collection must reflect 

the current plant operations and 

distribution system. EPA’s IDSE 

Guidance Manual will include a 

guidance for system-specific studies and 

how to determine whether site-specific 

data could be sufficient to meet the 

IDSE requirements (USEPA 2003j). 

iii. 40/30 certification. Under this 

approach, systems certify to their 

primacy agency that all required Stage 

1 DBPR compliance samples were 

properly collected and analyzed during 

the two years prior to the start of the 

IDSE, and all individual compliance 

samples were ≤ 0.040 mg/L for TTHM 

and ≤0.030 mg/L for HAA5. Properly 

collected and analyzed compliance 

samples are those taken at required 

locations at times specified in the 

system’s Stage 1 DBPR monitoring plan 

and analyzed by certified laboratories. 

Systems not required to collect Stage 1 

DBPR compliance samples can not 

utilize the 40/30 certification approach 

because they do not have data to 

determine sampling locations that 

represent high concentrations of TTHMs 

and HAA5. Systems that qualify for 

reduced monitoring for the Stage 1 

DBPR during the two years prior to the 

start of the IDSE, may use results of both 

routine and reduced Stage 1 DBPR 

monitoring to prepare the 40/30 

certification. Large ground water 

systems may not have two years of 

HAA5 data to evaluate due to the timing 

of the Stage 1 DBPR and the IDSE 

requirements. EPA is proposing that, if 

two years worth of HAA5 data are not 

available, large ground water systems 

evaluate the most recent two years of 

TTHM data including data collected in 

accordance with the 1979 TTHM rule 

and all available HAA5 compliance data 

collected up to nine months following 

promulgation of this rule when making 

the 40/30 certification. Similarly, small 

wholesale and consecutive systems 

required to submit their IDSE report no 

later than two years after publication of 

the final rule will evaluate all available 

Stage 1 DBPR compliance data collected 

up to nine months following 

promulgation. 

c. Implementation. All systems 

subject to the IDSE requirement under 

the proposed rule (except those 

receiving a very small system waiver 

from the State) must submit a report to 

the primacy agency. The requirements 

for the report depend upon the IDSE 

data collection alternative that the 

system selects and are listed in Table V–

2.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49593

TABLE V–2.—IDSE REPORT REQUIREMENTS

IDSE data collection 

alternative IDSE report requirements 

Standard Monitoring Program.• All standard monitoring program TTHM and HAA5 analytical results, the original monitoring plan, and an explanation of any deviations from that plan. 

• A schematic of the distribution system. 

• Recommendations and justification for where and during what month(s) Stage 2B monitoring should be conducted. 

System Specific Study ......... • All studies, reports, analytical results and modeling. 

• A schematic of the distribution system. 

• Recommendations and justification for where and during what month(s) Stage 2B monitoring should be conducted 

40/30 Certification ................ • A certification that all required compliance samples were properly collected and analyzed during the two years 

prior to the start of the IDSE and all individual compliance samples were ≤ 0.040 mg/L for TTHM and ≤0.030 

mg/L for HAA5. 

• Results of compliance samples taken after the IDSE was scheduled to begin and before the IDSE report was 

submitted. 

• Recommendations for where and during what month(s) Stage 2B monitoring should be conducted. 

All IDSE reports must include 

recommendations for the location and 

schedule for the Stage 2B monitoring. 

The number of sampling locations and 

the criteria for their selection are 

described in § 141.605 of today’s 

proposed rule, and in section V.I. 

Generally, a system must recommend 

locations with the highest LRAAs unless 

it provides a rationale (such as ensuring 

geographical coverage of the 

distribution system instead of clustering 

all sites in a particular section of the 

distribution system) for selecting other 

locations. Systems must consider both 

their compliance data and IDSE data in 

making this determination. In addition 

to specifying a protocol for identifying 

recommended monitoring sites in the 

rule language, EPA will provide 

guidance for recommending compliance 

monitoring sites (including rationales 

for systems to recommend sites that do 

not have the highest LRAA 

concentrations) and preparing the IDSE 

report. EPA will also provide a process 

to address IDSE implementation issues 

during the period prior to State primacy. 

At the time that systems serving fewer 

than 10,000 people conduct their 

monitoring or analyze their site-specific 

data, many States may have primacy. 

The compliance schedules for the 

IDSE and other requirements of the 

proposed rule are described in detail in 

section V.J. Systems serving at least 

10,000 people (and those smaller 

wholesale and consecutive systems 

associated with larger systems) will be 

collecting data for their IDSE prior to 

State primacy. EPA intends to have an 

IDSE Guidance Manual available to 

assist systems in performing the IDSE 

(USEPA 2003j). Primacy agencies will 

specify requirements for systems that do 

not submit an IDSE report, or that have 

not, in the determination of the primacy 

agency, conducted an adequate IDSE, in 

addition to giving the system a 

monitoring and reporting violation. 

These requirements may include 

repeating the IDSE while conducting 

compliance monitoring at Stage 1 

monitoring sites or conducting Stage 2 

compliance monitoring at sites selected 

by the State. 

Consecutive systems are subject to the 

IDSE requirements of today’s proposed 

rule. IDSE requirements for consecutive 

systems are largely the same as for other 

systems, but with two differences. First, 

the schedule for completion of the IDSE 

by a consecutive system is dependent 

upon the population of the wholesale 

system. If a consecutive system serving 

fewer than 10,000 buys water from a 

system that serves 10,000 or more 

people, then this consecutive system 

must comply within the same schedule 

as that for systems ≥ 10,000. Conversely, 

if a wholesale system serves < 10,000 

but sells water to a consecutive system 

serving ≥ 10,000, then both the 

wholesale system and the consecutive 

system must complete the IDSE within 

the same schedule as that for systems ≥

10,000. The second difference for 

consecutive systems is that the 

procedure for recommending Stage 2B 

compliance monitoring locations is 

modified for consecutive systems 

purchasing or receiving all of their 

finished water from a wholesale system. 

These modified procedures are 

described in § 141.605 of today’s 

proposed rule, and in section V.I. 

2. How Was This Pr oposal Developed? 

The IDSE was recommended by the 

Stage 2 M–DBP Advisory Committee. 

The Advisory Committee believed that 

maintaining Stage 1 DBPR sampling 

sites for the Stage 2 DBPR would not 

accomplish the objective of providing 

consistent and equitable protection 

across the distribution system.

a. Applicability. The M–DBP 

Advisory Committee recommended that 

an IDSE be performed on all community 

systems to help to identify the locations 

in the distribution system that represent 

high DBP concentrations. EPA believes 

that large nontransient noncommunity 

water systems (those serving at least 

10,000 people) also have distribution 

systems that require further evaluation 

to determine the most representative 

locations of high DBP levels. Therefore, 

large nontransient noncommunity 

systems and all community systems are 

required to perform an IDSE under 

today’s proposal. 

States may waive the IDSE 

requirement for those very small 

systems (systems that serve fewer than 

500 people) that monitor for Stage 1 

DBPR compliance at the maximum 

residence time site if the State 

determines their maximum residence 

time Stage 1 compliance monitoring site 

is likely to capture both the high TTHM 

and high HAA5 levels within the 

distribution system. The Advisory 

Committee recommended this waiver be 

included because many very small 

systems have small distribution systems 

and the high TTHM and high HAA5 site 

is at the same location. The Advisory 

Committee also recognized that not all 

very small systems have a single 

monitoring site that would represent 

both high TTHM and high HAA5 levels 

(e.g., some rural systems with large 

distribution systems) and thus did not 

recommend a blanket IDSE waiver for 

all very small systems. 

b. Data collection. The data collection 

requirements of the IDSE are designed 

to find both high TTHM and high HAA5 

sites (see section V.I. for IDSE 

monitoring site locations). The IDSE is 

intended as a one-time requirement. 

High TTHM and HAA5 concentrations 

often occur at different locations in the

49594 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

distribution system. The Stage 1 DBPR 

monitoring sites identified as the 

maximum location are selected 

according to residence time. Because 

HAAs can degrade in the distribution 

system in the absence of sufficient 

disinfectant residual (Baribeau et al.

2000), residence time alone is not an 

ideal criterion for identifying high 

HAA5 sites. The Information Collection 

Rule data show that of the four 

monitoring locations sampled per 

system, the one identified as the 

maximum residence time location was 

often not the location where the highest 

DBP levels were found. In fact, over 60 

percent of the highest HAA5 LRAAs and 

50 percent of the highest TTHM LRAAs 

were found at sampling locations in the 

system other than the maximum 

residence time location (see section IV). 

Thus the method and assumptions used 

to select the Information Collection Rule 

monitoring sites, and the Stage 1 DBPR 

compliance monitoring sites, are not 

sufficiently reliable to select Stage 2 

DBPR compliance monitoring sites that 

will capture high DBP levels. 

This data analysis reveals that a 

reevaluation of monitoring sites is 

necessary at many systems to capture 

sites with high DBP levels. The 

Advisory Committee recommended 

sample locations (based on distribution 

disinfectant type) at widely distributed 

sites (see section V.I. for details on IDSE 

monitoring requirements). Monitoring at 

additional sites across the distribution 

system increases the chance of finding 

sites with high DBP levels and targets 

both DBPs that degrade, and DBPs that 

form, as residence time increases in the 

distribution system. EPA believes that 

the required number of monitoring 

locations plus Stage 1 monitoring 

results provides an adequate 

recharacterization of DBP levels 

throughout the distribution system, at a 

reasonable cost. With a 

recharacterization of distribution 

systems that focuses on both high 

TTHM and HAA5 occurrence, EPA 

believes that high occurrence sites will 

be better represented in this standard 

monitoring program. Systems will be 

required to take steps to address high 

DBP levels at points that might 

otherwise have gone undetected. EPA 

believes that the decrease in DBP 

exposure anticipated to result from the 

transition from an RAA to an LRAA will 

be augmented by the IDSE. 

The frequency and number of samples 

required for the standard monitoring 

program decrease as system size 

(population served) decreases and 

depend on source water type. The 

Advisory Committee believed that the 

number of samples required for large 

and medium surface water systems was 

not necessary for small surface water 

systems and ground water systems. The 

majority of small systems have 

distribution systems with simpler 

designs than large systems. DBP 

occurrence in ground water systems is 

generally lower and less variable than in 

surface water systems due to lower and 

less variable precursor levels and much 

less temperature variation (see section 

IV). 

Committee members recognized that 

some systems have detailed knowledge 

of their distribution systems by way of 

hydraulic modeling and/or ongoing 

widespread monitoring plans (well 

beyond that required for compliance 

monitoring) that would provide 

equivalent or superior monitoring site 

selection compared to IDSE monitoring. 

Therefore, the Advisory Committee 

recommended that such systems be 

allowed to determine new monitoring 

sites using system-specific data such as 

historical monitoring data. 

Systems that certify to their State that 

all compliance samples taken in the two 

years prior to the start of the IDSE were 

≤ 0.040 mg/L TTHM and ≤ 0.030 mg/L 

HAA5 are not required to collect 

additional DBP monitoring data because 

the Advisory Committee determined 

that these systems most likely would 

not have high peak DBP levels. EPA 

determined that this provision needed 

to be more specific for three groups of 

systems: (1) Those performing Stage 1 

DBPR reduced monitoring, (2) large 

ground water systems, and (3) small 

systems required to conduct an early 

IDSE. Today’s proposal clarifies that 

these systems may use a 40/30 

certification. EPA recognizes that these 

systems may have less compliance data 

on which to base their 40/30 

certifications. However, EPA believes 

that the data that will be available are 

sufficient to make a determination on 

the most appropriate Stage 2B 

monitoring locations. 

c. Implementation. Systems are 

required to submit an IDSE report so 

that primacy agencies may review the 

system’s IDSE data collection efforts and 

the Stage 2B monitoring locations 

recommended by the system. Systems 

serving at least 10,000 must submit their 

IDSE report two years after rule 

promulgation (which may be prior to 

primacy for some States). The M–DBP 

Advisory Committee recommended an 

implementation schedule that would 

allow systems sufficient time to make 

site-specific risk determinations and 

decisions regarding the simultaneous 

implementation of the Stage 2 DBPR 

and LT2ESWTR but not stretch out the 

compliance time frame too far into the 

future. This provision requires that 

medium and large systems conduct and 

complete site-specific risk 

determinations (i.e., the IDSE and 

LT2ESWTR Cryptosporidium

monitoring) as soon as possible after 

rule promulgation. Since small systems 

cannot begin their microbial monitoring 

until after the results from the large 

system microbial monitoring have been 

analyzed, small systems have a longer 

compliance time frame. 

Systems that submit a 40/30 

certification are required to submit that 

certification as part of the IDSE report 

and to include a recommended Stage 2B 

monitoring plan. The monitoring plan is 

required for these systems because the 

Stage 2B MCL compliance monitoring 

sites proposed today have 

fundamentally different objectives than 

the Stage 1 DBPR monitoring sites. 

Additionally, many systems are 

required to have more Stage 2 

compliance monitoring sites than Stage 

1 sites because high HAA5 site may be 

different than high TTHM sites. 

3. Request for Comment 

EPA requests comments on the IDSE 

requirement and whether it is a good 

tool to identify sites representative of 

high TTHM and high HAA5 levels. 

a. Applicability. EPA requests 

comment on requiring large (serving 

10,000 or more people) nontransient 

noncommunity water systems to 

perform an IDSE. Should NTNCWSs 

serving fewer than 10,000 people be 

required to conduct an IDSE? EPA also 

requests comment upon whether States 

should be able to waive IDSE 

requirements for very small systems 

(serving fewer than 500 people). Are 

there objective criteria that the State 

should use in waiving the requirement? 

Should the State be allowed to grant 

very small system waivers based on 

some other criterion other than serving 

a population <500? For example, should 

the State be allowed to choose a higher 

population cutoff? Should the State be 

allowed to use a non-population 

criterion such as simplicity of 

distribution system to grant a very small 

system waiver? If so, what should this 

criterion be and how should 

qualification be demonstrated? 

b. Data collection. EPA requests 

comment on the requirements for each 

of the alternatives for data collection 

under the proposed IDSE including: the 

standard monitoring program, the 

system-specific study, and the 40/30 

certification. EPA requests comment on 

whether systems with less than two 

years of routine monitoring data should 

be considered to have sufficient data to 

utilize the 40/30 certification.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49595

Specifically EPA requests comment on 

whether systems on reduced 

monitoring, large ground water systems, 

and small systems required to conduct 

an IDSE within the first two years after 

promulgation should be prohibited from 

submitting a 40/30 certification. 

c. Implementation. EPA requests 

comment on the requirement that large 

and medium systems must collect data 

and prepare their IDSE report prior to 

State primacy. EPA requests comment 

from the States regarding whether they 

intend to be involved in the 

consultations with systems collecting 

data for IDSE or in the review of IDSE 

reports that are submitted prior to State 

primacy. EPA is developing a plan to 

implement the IDSE during the period 

prior to State primacy. EPA requests 

comment on any issues that should be 

addressed during this period to facilitate 

the IDSE.

I. Monitoring Requirements and 

Compliance Determination for Stage 2A 

and Stage 2B TTHM and HAA5 MCLs 

1. What Is EPA Proposing Today? 

Today’s proposal includes new 

requirements for how systems must 

monitor TTHM and HAA5 levels in 

their distribution systems and how 

systems must assess their monitoring 

results to determine compliance with 

TTHM and HAA5 MCLs. The new 

monitoring requirements are associated 

with the IDSE (described in section V.H) 

and Stage 2B of the proposed rule. The 

new compliance determination 

requirements relate to use of the 

locational running annual average 

(LRAA) for meeting proposed Stage 2A 

and Stage 2B MCLs for TTHM and 

HAA5 (described in section V.D). This 

section presents these proposed 

monitoring and compliance 

determination requirements for Stage 

2A, the IDSE, and Stage 2B. 

An important aspect of the proposed 

TTHM and HAA5 monitoring 

requirements is the use of two different 

approaches for determining the number 

of samples a system is required to 

collect. One approach is plant-based. 

Under the plant-based approach, a 

system’s TTHM and HAA5 sampling 

requirements are determined by the 

number of treatment plants in the 

system and, in the case of consecutive 

systems, the number of consecutive 

system entry points. The second 

approach is population-based. Under 

the population-based approach, a 

system’s sampling requirements are 

influenced by the number of people 

served, but not by the number of 

treatment plants. EPA is proposing 

population-based sampling 

requirements only for IDSE and Stage 

2B monitoring by consecutive systems 

that purchase all of their finished water 

year-round. However, EPA is requesting 

comment on applying a populationbased approach to all systems for the 

IDSE and Stage 2B compliance. The 

discussion of monitoring requirements 

in this section provides details on these 

two approaches. 

A number of factors affect DBP 

formation, including the type and 

amount of disinfectant used, water 

temperature, pH, amount and type of 

precursor material in the water, and the 

length of time that water remains in the 

treatment and distribution systems. For 

this reason, and because DBP levels can 

be highly variable throughout the 

distribution system (as discussed in 

section IV), today’s proposal requires 

systems to collect IDSE and Stage 2B 

samples at specific locations in the 

distribution system and in accordance 

with a sampling schedule. For purposes 

of determining the number of required 

samples, EPA intends to maintain the 

provision in the Stage 1 DBPR 

(§ 141.132(a)(2)) that multiple wells 

drawing raw water from a single aquifer 

may, with State approval, be considered 

one plant, and prior approvals will 

remain in force unless withdrawn. 

a. Stage 2A. For Stage 2A of the 

proposed rule, compliance will be based 

on the compliance sampling sites and 

frequency established under the existing 

Stage 1 DBPR. Systems must continue to 

monitor for TTHM and HAA5 using a 

plant-based approach, as required under 

40 CFR 141.132. Using these monitoring 

results, systems must continue to 

demonstrate compliance with Stage 1 

MCLs of 0.080 mg/L for TTHM and 

0.060 mg/L for HAA5, based on a 

running annual average (see 40 CFR 

141.133). In addition, systems must 

comply with the Stage 2A MCLs of 

0.120 mg/L for TTHM and 0.100 mg/L 

for HAA5, based on the LRAA at each 

Stage 1 DBPR monitoring location. Stage 

1 DBPR provisions for systems to reduce 

the frequency of TTHM and HAA5 

monitoring will still apply. 

Stage 2A will primarily affect surface 

water systems serving at least 10,000 

people or systems with multiple plants, 

because these systems are required to 

monitor at more than one location in the 

distribution system. Most other systems 

take compliance samples at only one 

location under Stage 1 and in these 

cases, the calculated LRAA will be 

equal to the calculated RAA. 

b. IDSE. IDSE monitoring 

requirements are designed to identify 

locations within the distribution system 

with high TTHM and HAA5 levels, 

which will serve as Stage 2B monitoring 

sites. The following discussion provides 

details on the IDSE standard monitoring 

program. Section V.H identifies other 

approaches by which systems can meet 

IDSE requirements of the rule. 

For IDSE monitoring, subpart H 

systems serving at least 10,000 people 

must collect samples approximately 

every 60 days at eight distribution 

system sites per plant (these are in 

addition to Stage 1 DBPR compliance 

monitoring sites). The distribution 

system residual disinfectant type 

determines the location of the eight 

sites, as shown in Table V–3. 

Subpart H systems serving fewer than 

10,000 people and all ground water 

systems must collect IDSE samples at 

two distribution system sites per plant 

(at sites that are in addition to the Stage 

1 DBPR compliance monitoring sites) as 

shown in Table V–3. Subpart H systems 

serving 500–9,999 people and ground 

water systems serving at least 10,000 

people must sample quarterly 

(approximately every 90 days); subpart 

H systems serving fewer than 500 

people and ground water systems 

serving fewer than 10,000 people must 

sample semi-annually (approximately 

every 180 days). 

EPA is also proposing IDSE 

monitoring requirements for 

consecutive systems. For consecutive 

systems that both purchase finished 

water and treat source water to produce 

finished water, IDSE requirements are 

the same as for non-consecutive systems 

with the same population and source 

water type (see Table V–3). For these 

consecutive systems, each consecutive 

system entry point (defined in section 

V.C) is counted as one treatment plant 

for purposes of determining sampling 

requirements. However, the State may 

allow a system to consider multiple 

consecutive system entry points to be 

considered a single point. 

As noted previously, for consecutive 

systems that purchase all of their 

finished water year-round, EPA is 

proposing a population-based 

monitoring approach (see Table V–4) 

instead of a plant-based approach. 

Under the population-based approach, 

monitoring requirements are not 

influenced by the number of 

consecutive system entry points, but are 

based solely on the population served 

and the type of source water used. EPA 

believes the population-based approach 

is equitable and will provide 

representative DBP concentrations 

throughout distribution systems.

49596 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

TABLE V–3.—PROPOSED IDSE MONITORING REQUIREMENTS

System type and population 

served 

Distribution system disinfectant 

type 

Number 

of monitoring 

periods 

Distribution system sample locations per plant per monitoring period 1

Total 

Near 

entry 

point 

Average 

residence 

time 

High 

TTHM 

locations 

High 

HAA5 

locations 

Subpart H ≥10,000 ....................... Chloramines .................................. 26 8 2 2 2 2 

Chlorine ........................................ 26 8 1 2 3 2 

Subpart H 500–9,999 or Ground 

Water ≥10,000.

Any ................................................ 3 4 2 0 0 1 1 

Subpart Any H <500 or Ground 

Water <10,000.

Any ................................................ 2 4 2 0 0 1 1 

Consecutive Systems ................... Any ................................................ —Consecutive systems that purchase 100% of their finished water 

year-round—see Table V.4. 

—Consecutive systems that also treat source water to produce finished 

water—plant-based monitoring at same location and frequency as a 

non-consecutive system with the same population and source water. 

1Samples must be taken at locations other than the existing Stage 1 DBPR monitoring locations. Dual sample sets (i.e., a TTHM and an HAA5 

sample) must be taken at each site. Sampling locations should be distributed throughout the distribution system. 2Approximately every 60 days. 

3Approximately every 90 days. 

4Approximately every 180 days. 

TABLE V–4. POPULATION-BASED MONITORING FREQUENCIES AND LOCATIONS UNDER IDSE FOR CONSECUTIVE SYSTEMS

THAT PURCHASE 100% OF FINISHED WATER YEAR-ROUND

Source water type Population size category Monitoring periods and 

frequency 

Distribution system sample locations 1

Total 

Near 

entry 

points 2

Average 

residence 

time 

High 

TTHM 

locations 

High 

HAA5 

locations 

Subpart H ......................... 0–499 .............................. Two 2 every 180 days) ... 2 ................ ................ 1 1 

500–4,999 ....................... Four (every 90 days) ....... 2 ................ ................ 1 1 

5,000–9,999 .................... 4 ................ 1 2 1 

10,000-24,999 ................. Six (every 60 days) ......... 8 1 2 3 2 

25,000-49,999 ................. 12 2 3 4 3 

50,000-99,999 ................. 16 3 4 5 4 

100,000-499,999 ............. 24 4 6 8 6 

500,000-1,499,000 .......... 32 6 8 10 8 

1,500,000-4,999,999 ....... 40 8 10 12 10 

≥5,000,000 ...................... 48 10 12 14 12 

Ground Water ................... 0–499 .............................. Two (every 180 days) ..... 2 ................ ................ 1 1 

500–9,999 ....................... 2 ................ ................ 1 1 

10,000-99,999 ................. Four (every 90 days) ....... 6 1 1 2 2 

100,000-499,999 ............. 8 1 1 3 3 

≥500,000 ......................... 12 2 2 4 4 

1Samples must be taken at locations other than the existing Stage 1 DBPR monitoring locations. Dual sample sets (i.e., a TTHM and an HAA5 

sample) must be taken at each site. Sampling locations should be distributed throughout the distribution system. 2 If the number of entry points to the distribution system is less than the specified number of sampling locations, additional samples must be 

taken equally at high TTHM and HAA5 locations. If there is an odd extra location number, a sample at a high TTHM location must be taken. If 

the number of entry points to the distribution system is more than the specified number of sampling locations, samples must be taken at entry 

points to the distribution system having the highest water flows. 

As a part of the monitoring schedule, 

all systems conducting IDSE monitoring 

must collect samples during the peak 

historical month for TTHM levels or 

water temperature. EPA will provide 

guidance to assist systems in choosing 

IDSE monitoring locations, including 

criteria for selecting high TTHM and 

HAA5 monitoring locations. 

c. Stage 2B. For those systems 

required to conduct an IDSE, Stage 2B 

monitoring sites are based on the 

system’s IDSE results and Stage 1 DBPR 

compliance monitoring results. For 

those systems not required to conduct 

an IDSE, Stage 2B monitoring locations 

are based on the system’s Stage 1 DBPR 

compliance monitoring results and an 

evaluation of the distribution system 

characteristics to identify additional 

monitoring locations, if required. 

Consistent with the Advisory 

Committee recommendations, the 

monitoring frequency for Stage 2B is 

structured so that systems that monitor 

quarterly under the Stage 1 DBPR will 

continue to monitor quarterly. In 

addition, the monitoring schedule must 

include the month with the highest 

historical DBP concentrations. 

Many systems on reduced monitoring 

under the Stage 1 DBPR will conduct 

Stage 2B compliance monitoring at 

different or additional locations than 

those used for Stage 1 compliance 

monitoring. Such systems must conduct 

routine monitoring for at least one year 

before being eligible for reduced 

monitoring under Stage 2B. Those 

systems that monitor at the same 

locations under both the Stage 1 DBPR 

and Stage 2B DBPR and have qualified 

for reduced monitoring under Stage 1 

may remain on reduced monitoring at 

the beginning of Stage 2B.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49597

EPA is proposing to require all 

systems to develop and maintain a DBP 

monitoring plan that must include the 

following information: monitoring 

locations, monitoring dates, compliance 

calculation procedures, and copies of 

any permits, contracts, or other 

agreements with third parties to sample, 

analyze, report, or perform any other 

monitoring requirement. Each system in 

a combined distribution system (as 

discussed in section V.C) must develop 

and maintain its own monitoring plan. 

To comply with the requirement for a 

monitoring plan, systems may develop a 

new plan or update the monitoring plan 

required under the Stage 1 DBPR (see 

§ 141.132(f)). In either case, the system 

must follow the monitoring plan, which 

will be based on the IDSE report 

submitted to the State, modified by any 

changes required by the State. 

Table V–5 summarizes proposed 

routine and reduced monitoring 

requirements for Stage 2B of today’s rule 

for non-consecutive systems and for 

consecutive systems that also treat 

source water. Tables V–6 and V–7 

summarize proposed routine and 

reduced Stage 2B monitoring 

requirements for consecutive systems 

that purchase all of their finished water 

year-round. The proposed reduced 

monitoring requirements are consistent 

with the approach taken in the Stage 1 

DBPR.

TABLE V–5.—PROPOSED STAGE 2B ROUTINE AND REDUCED MONITORING REQUIREMENTS FOR NON-CONSECUTIVE

SYSTEMS AND FOR CONSECUTIVE SYSTEMS THAT ALSO TREAT SOURCE WATER TO PRODUCE FINISHED WATER 1

System size and source 

water type 

Routine monitoring (per 

plant) 2

Requirements to qualify for reduced 

monitoring 

Reduced monitoring 

(per plant) 

Trigger for returning to 

routine monitoring 

Subpart H systems serving ≥10,000 people.Four dual sample sets 

per quarter.

One year of completed routine monitoring and all TTHM and HAA5 

LRAAs are no more than 0.040 

mg/L and 0.030 mg/L, respectively, and TOC running annual 

average ≤4.0 mg/L.

Two dual sample sets 

per quarter.

TOC >4.0 mg/L as an 

RAA, or TTHM LRAA 

>0.040 mg/L or HAA5 

LRAA >0.030 mg/L. 

Subpart H systems serving 500 to 9,999 people.Two dual sample sets 

per quarter 3.

One year of completed routine monitoring and all TTHM and HAA5 

LRAAs are no more than 0.040 

mg/L and 0.030 mg/L, respectively, and TOC running annual 

average ≤4.0 mg/L.

Two dual sample sets 

per year 4.

TOC >4.0 mg/L as an 

RAA, or Single Sample of TTHM >0.060 

mg/L or HAA5 >0.045 

mg/L.5

Subpart H systems serving <500 people.One dual sample set 

per year 5 6.

Monitoring may not be reduced ....... NA ................................. NA. 

Ground water systems 

serving ≥10,000 people 7.

Two dual sample sets 

per quarter 3.

One year of completed routine monitoring and all TTHM and HAA5 

LRAAs are no more than 0.040 

mg/L and 0.030 mg/L, respectively.

Two dual sample sets 

per year 4.

Single Sample of TTHM 

>0.060 mg/L or HAA5 

>0.045 mg/L.5

Ground water systems 

serving 500 to 9,999 

people 7.

Two dual sample sets 

per year 3 5.

One year of completed routine monitoring and all TTHM and HAA5 

LRAAs are no more than 0.040 

mg/L and 0.030 mg/L, respectively.

Two dual samples every 

third year 4.

Single sample of TTHM 

>0.040 mg/L or HAA5 

>0.030 mg/L.5

Ground water systems 

serving <500 people 7.

One dual sample set 

per year 5 6.

One year of completed routine monitoring and all TTHM and HAA5 

LRAAs are no more than 0.040 

mg/L and 0.030 mg/L, respectively.

Two dual samples every 

third year 4.

Single sample of TTHM 

>0.040 mg/L or HAA5 

>0.030 mg/L 5

Consecutive systems 

that also treat source 

water.

System must meet the routine and reduced monitoring requirements of a non-consecutive system with the same population and source water. Monitoring may be reduced to the level required of that non-consecutive system. 

1Samples must be taken during representative operating conditions. Quarterly samples must be taken approximately every 90 days. 

2Systems will use the results of their IDSEs and Stage 1 DBPR compliance monitoring to recommend Stage 2B monitoring locations representative of high TTHM and HAA5 concentrations to the State in their IDSE reports. Systems must monitor at the recommended locations unless the State requires other locations. 3 If site and quarter of highest individual TTHM and HAA5 measurement are the same, monitoring is only required at one location if State approves. 4 If site and quarter of highest individual TTHM and HAA5 measurement are the same, monitoring is only required at one location. 

5 If any single sample of TTHM >0.080 mg/L or HAA5 >0.060 mg/L, system must go to increased monitoring of quarterly dual samples at each 

routine monitoring location and can return to routine monitoring when TTHM ≤0.060 mg/L and HAA5 ≤0.045 mg/L as LRAAs. 6 If the site or month of highest TTHM is not the same as the site or month of highest HAA5, the system must monitor for TTHM at the location 

of the highest TTHM LRAA during the month of highest TTHM single measurement and for HAA5 at the location of the highest HAA5 LRAA during the month of highest HAA5 single measurement. 7Ground water systems are those not under the direct influence of surface water. For the purpose of determining the required number of samples, multiple wells drawing water from a single aquifer may, with State approval, be considered one treatment plant. 

i. Subpart H systems serving 10,000 or 

more people. 

Routine monitoring: Systems must 

take four dual sample sets (i.e., a TTHM 

and an HAA5 sample must be taken at 

each sampling site) per treatment plant 

per quarter. Systems must monitor at 

locations recommended in the IDSE 

report, unless the State has required 

other locations. Most systems must take 

samples at each plant in the system as 

follows: One dual sample set at the 

existing Stage 1 DBPR average residence 

time monitoring location with the 

highest TTHM or HAA5 LRAA, one 

dual sample set at a point representative 

of the highest HAA5 levels, and two 

dual sample sets at points representative 

of the highest TTHM levels. 

Systems must schedule monitoring so 

that one quarter’s monitoring is 

conducted during the peak historical 

month for high TTHM concentration 

and the other quarterly monitoring is

49598 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

conducted approximately every 90 days 

on a predetermined schedule included 

in the system’s monitoring plan. 

Reduced monitoring: Only systems 

with source water TOC ≤4.0 mg/L as an 

RAA that have completed at least one 

year of routine monitoring may qualify 

for reduced monitoring (see Table V–5). 

Systems that have a TTHM LRAA 

≤0.040 mg/L and an HAA5 LRAA 

≤0.030 mg/L at all sites, in addition to 

a source water TOC RAA ≤ 4.0 mg/L, 

may reduce the monitoring frequency 

for TTHM and HAA5 to two dual 

sample sets (one each at sites 

representative of the highest HAA5 and 

TTHM LRAAs) per treatment plant per 

quarter. Systems on a reduced 

monitoring schedule may remain on 

that reduced schedule as long as the 

LRAA of all samples taken in the year 

is no more than 0.040 mg/L for TTHM 

and 0.030 mg/L for HAA5 or if source 

water TOC exceeds 4.0 mg/L as an RAA. 

Systems must revert to routine 

monitoring in the quarter immediately 

following any quarter in which the 

LRAA for any monitoring location 

exceeds 0.040 mg/L for TTHM or 0.030 

mg/L for HAA5. Additionally, the State 

may return a system to routine 

monitoring at the State’s discretion. 

Compliance determination: A PWS is 

in compliance with Stage 2B when the 

TTHM and HAA5 LRAAs for each 

sample location, computed quarterly, 

are less than or equal to the Stage 2B 

MCLs of 0.080 mg/L and 0.060 mg/L, 

respectively. Otherwise, the system is 

out of compliance. 

ii. Subpart H systems serving 500 to 

9,999 people. Routine monitoring: 

Systems must monitor quarterly for each 

treatment plant by taking two dual 

sample sets, one each at sites 

representative of high HAA5 levels and 

high TTHM levels (as recommended in 

the IDSE report). However, if the State 

determines that the sites representative 

of the high TTHM and HAA5 levels are 

at the same location, the State may 

determine that the system is only 

required to monitor at one site per 

treatment plant. 

Systems must conduct quarterly 

monitoring during the peak historical 

month for TTHM with quarterly 

samples taken approximately every 90 

days on a predetermined schedule 

specified in the system’s monitoring 

plan. All samples must be taken as dual 

sample sets (i.e., a TTHM and an HAA5 

sample must be taken at each site). 

Reduced monitoring: To qualify for 

reduced monitoring, systems must meet 

certain prerequisites (see Table V–5). 

Systems eligible for reduced monitoring 

may reduce the monitoring frequency 

from quarterly to annually. Samples 

must be taken during the month(s) of 

peak historical TTHM and HAA5 levels 

at the same locations specified under 

routine monitoring. Systems that have 

their highest TTHM and HAA5 levels in 

the same month must take dual sample 

sets at both the high TTHM and high 

HAA5 sites. If the high months for 

TTHM and HAA5 are not the same, the 

system must take dual sample sets in 

both the high TTHM and high HAA5 

months. Systems on a reduced 

monitoring schedule may remain on 

that reduced schedule as long as the 

annual sample taken at each location is 

no more than 0.060 mg/L for TTHM and 

0.045 mg/L for HAA5 or if source water 

TOC exceeds 4.0 mg/L as an RAA. 

Systems that do not meet these levels 

must revert to routine monitoring in the 

quarter immediately following the 

quarter in which the system exceeded 

0.060 mg/L for TTHM or 0.045 mg/L for 

HAA5. Additionally, the State may 

return a system to routine monitoring at 

the State’s discretion. 

Compliance determination: A PWS is 

in compliance with Stage 2B when the 

LRAAs of each sample location, 

computed quarterly, are less than or 

equal to the MCLs. Otherwise, the 

system is out of compliance. If the 

annual sample taken under reduced 

monitoring exceeds the MCL, the system 

must resume quarterly monitoring but is 

not immediately in violation of the 

MCL. The system is out of compliance 

if the LRAA of the quarterly sample for 

the past four quarter exceeds the MCL. 

iii. Subpart H systems serving fewer 

than 500 people. Routine monitoring: 

Systems are required to sample annually 

for each treatment plant at the location 

with high TTHM and HAA5 values 

during the month of peak historical 

TTHM levels. The system must take one 

dual sample set at the site representative 

of the high HAA5 and TTHM levels (at 

the Stage 1 DBPR monitoring site or as 

recommended in the IDSE report), 

unless the State determines that the 

highest TTHM site and the highest 

HAA5 site are not at the same location 

or are not during the same quarter. If the 

State determines that the highest TTHM 

and highest HAA5 do not occur in the 

same location, the system is required to 

take two samples, an HAA5 sample at 

the site representative of the high HAA5 

levels and a TTHM sample at the site 

representative the high TTHM levels. If 

the State determines that the highest 

TTHM and highest HAA5 do not occur 

in the same quarter, the systems is 

required to take one sample in the high 

TTHM quarter and one sample in the 

high HAA5 quarter. If the annual 

sample exceeds the MCL for either 

TTHM or HAA5, the system must 

monitor quarterly at the previously 

determined monitoring locations. 

Reduced monitoring: These systems 

may not reduce monitoring to less 

frequently than annually. Systems on 

increased (quarterly) monitoring may 

return to routine monitoring if the 

LRAAs of quarterly samples are no more 

than 0.060 mg/L for TTHM and 0.045 

mg/L for HAA5. 

Compliance determination: A PWS is 

in compliance when the annual sample 

(or LRAA of quarterly samples, if 

increased or additional monitoring is 

conducted) is less than or equal to the 

MCL. If the annual sample exceeds the 

MCL, the system must conduct 

increased (quarterly) monitoring but is 

not immediately in violation of the 

MCL. The system is out of compliance 

if the LRAA of the quarterly samples for 

the past four quarters exceeds the MCL. 

iv. Ground water systems serving 

10,000 or more people. Routine 

monitoring: Systems are required to 

monitor quarterly for each treatment 

plant in the system by taking two dual 

sample sets, one each at sites 

representative of high HAA5 levels and 

high TTHM levels (as recommended in 

the IDSE report). However, if the State 

determines that the sites representative 

of the high TTHM and HAA5 levels are 

the same, the State may determine that 

the system only has to monitor at one 

site per treatment plant. One quarterly 

sample must be taken during the peak 

historical month for TTHM, with 

subsequent quarterly samples taken 

approximately every 90 days. 

Reduced monitoring: To qualify for 

reduced monitoring, systems must meet 

certain requirements (see Table V–5). 

Systems eligible for reduced monitoring 

may reduce the monitoring frequency 

from quarterly to annually. Samples 

must be taken during the month(s) of 

peak historical TTHM and HAA5 levels 

at the same locations specified under 

routine monitoring. Systems that have 

their highest TTHM and HAA5 levels in 

the same quarter must take dual sample 

sets at both the high TTHM and high 

HAA5 sites. If the quarter for high 

TTHM and high HAA5 are not the same, 

the system must take dual sample sets 

in both the high TTHM and high HAA5 

quarters. Systems on a reduced 

monitoring schedule may remain on 

that reduced schedule as long as the 

annual sample taken at each location is 

no more than 0.060 mg/L for TTHM and 

0.045 mg/L for HAA5. Systems that do 

not meet these levels must revert to 

routine monitoring in the quarter 

immediately following the quarter in 

which the system exceeded 0.060 mg/L 

for TTHM or 0.045 mg/L for HAA5. 

Additionally, the State may return a

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49599

system to routine monitoring at the 

State’s discretion. 

Compliance determination: A PWS is 

in compliance with Stage 2B when the 

locational running annual average of 

each sample location, computed 

quarterly, is less than or equal to the 

MCL. Otherwise, the system is out of 

compliance. If the annual sample 

exceeds the MCL, the system must 

conduct increased (quarterly) 

monitoring but is not immediately in 

violation of the MCL. The system is out 

of compliance if the LRAA of the 

quarterly sample for the past four 

quarter exceeds the MCL. 

v. Ground water systems serving 

fewer than 10,000 people. Routine 

monitoring: Systems serving 500 to 

9,999 people are required to take two 

dual sample sets annually, one each at 

sites representative of high HAA5 levels 

and high TTHM levels (as 

recommended in the IDSE report). 

However, if the State determines that 

the sites representative of the high 

TTHM and HAA5 levels are the same, 

the State may allow the system to 

monitor at only one site per treatment 

plant. If the State makes a determination 

that high TTHM and high HAA5 occur 

in different quarters, the system must 

monitor accordingly. If the annual 

sample exceeds the MCL for either 

TTHM or HAA5, the system must 

monitor quarterly at the previously 

determined monitoring locations. 

Systems serving fewer than 500 

people are required to take one dual 

sample set at the site representative of 

both high HAA5 and TTHM levels, 

unless the State determines that the 

high TTHM site and the high HAA5 site 

are not at the same location. If the State 

makes this determination, the system is 

required to take samples at two 

locations, an HAA5 sample at the site 

representative of the high HAA5 levels 

and a TTHM sample at the site 

representative of the high TTHM levels. 

If the State makes a determination that 

high TTHM and high HAA5 occur in 

different quarters, the system must 

monitor accordingly. If the annual 

sample exceeds the MCL for either 

TTHM or HAA5, the system must 

monitor quarterly at the previously 

determined monitoring locations. 

Reduced monitoring: To qualify for 

reduced monitoring, systems must meet 

certain prerequisites (see Table V–5). 

Systems eligible for reduced monitoring 

may reduce the monitoring frequency 

for TTHM and HAA5 to every third 

year. Systems are required to take two 

water samples, at sites representative of 

high HAA5 and TTHM levels (as 

discussed under routine monitoring) 

during the month of peak TTHM levels. 

Systems on a reduced monitoring 

schedule may remain on that reduced 

schedule as long as the sample taken 

every third year is no more than 0.040 

mg/L for TTHM and 0.030 mg/L for 

HAA5. Systems that do not meet these 

levels must resume routine annual 

monitoring until their annual average is 

no more than 0.040 mg/L for TTHM and 

0.030 mg/L for HAA5.

Compliance determination: A PWS is 

in compliance when the annual sample 

(or LRAA of quarterly samples, if 

increased or additional monitoring is 

conducted) is less than or equal to the 

MCL. If the annual sample exceeds the 

MCL, the system must conduct 

increased (quarterly) monitoring but is 

not immediately in violation of the 

MCL. The system is out of compliance 

if the LRAA of the quarterly samples for 

the past four quarters exceeds the MCL. 

vi. Consecutive systems. Routine 

monitoring: Monitoring requirements 

are determined by whether the 

consecutive system purchases all of its 

finished water year-round or also treats 

source water, along with the population 

served and source water type of the 

wholesale system (unless the 

consecutive system also has a surface 

water or ground water under the direct 

influence of surface water (GWUDI) 

source and the wholesale system is only 

ground water, in which case the 

consecutive system is classified as a 

subpart H system). Section V.C. of 

today’s document provides a more 

detailed discussion of consecutive 

system issues. 

As noted earlier, for consecutive 

systems that purchase all their finished 

water year-round, EPA is proposing 

population-based monitoring. The 

proposed number of monitoring 

locations is based on the source water 

type of the wholesale system and 

consecutive system population. 

Proposed Stage 2B compliance 

monitoring requirements for 

consecutive systems that purchase all 

their finished water are contained in 

Table V–6. Consecutive systems that 

also treat source water to produce 

finished water must monitor at the same 

locations and same frequency as a nonconsecutive system with the wholesale 

system’s source water type and the 

consecutive system’s population.

TABLE V–6.—PROPOSED POPULATION-BASED ROUTINE MONITORING ROUTINE FREQUENCIES AND LOCATIONS UNDER

STAGE 2B FOR CONSECUTIVE SYSTEMS THAT PURCHASE ALL THEIR FINISHED WATER YEAR-ROUND

Source water type Population size category Monitoring 

frequency 1

Distribution system sample location 2

Total 

Highest 

TTHM 

locations 

Highest 

HAA5 

locations 

Existing 

stage 1 

compliance 

locations 3

Subpart H ................................................... 0–499 ............................. per year .............. 2 4 1 1 ....................

500–4,999 ...................... per quarter .......... 2 4 1 1 ....................

5,000–9,999 ................... per quarter .......... 2 1 1 ....................

10,000–24,999 ............... per quarter ......... 4 2 1 1 

25,000–49,999 ............... per quarter ......... 6 3 2 1 

50,000–99,999 ............... per quarter ......... 8 4 2 2 

100,000–499,999 ........... per quarter ......... 12 6 3 3 

500,000–1,499,000 ........ per quarter .......... 16 8 4 4 

1,500,000–4,999,999 ..... per quarter ......... 20 10 5 5 

≥5,000,000 ..................... per quarter ......... 24 12 6 6 

0–499 ............................. per year .............. 2 4 1 1 ....................

500–9,999 ...................... per year .............. 2 1 1 ....................

Ground Water ............................................. 10,000–99,999 ............... per quarter ......... 4 2 1 1 

100,000–499,999 ........... per quarter ......... 6 3 2 1 

≥500,000 ........................ per quarter .......... 8 4 2 2 

1All systems must take at least one dual sample set during month of highest DBP concentrations. Systems on quarterly monitoring must take 

dual sample sets approximately every 90 days. 

49600 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

2 Locations based on system recommendations for Stage 2B monitoring locations in IDSE report to the State, unless State requires different or 

additional locations. Locations should be distributed through distribution system to the extent possible. 3Alternate between highest HAA5 LRAA and highest TTHM LRAA locations among the existing Stage 1 compliance locations. If the number of 

existing Stage 1 compliance locations is fewer than the specified number for Stage 2B, alternate between highest HAA5 LRAA locations and 

highest TTHM LRAA locations from the IDSE. 4System is required to take individual TTHM and HAA5 samples at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same 

location. 

Reduced monitoring: Consecutive 

systems can qualify for reduced 

monitoring if the LRAA at each location 

is ≤0.040 mg/L for TTHM and ≤0.030 

mg/L for HAA5 based on at least one 

year of monitoring at Stage 2B locations. 

Consecutive systems that purchase all of 

their finished water year-round may 

reduce their monitoring as specified in 

Table V–7. Consecutive systems that 

also treat source water to produce 

finished must conduct reduced 

monitoring at the same locations and 

same frequency as a non-consecutive 

system with the wholesale system’s 

source water type and the consecutive 

system’s population.

TABLE V–7.—REDUCED MONITORING FREQUENCY FOR CONSECUTIVE SYSTEMS THAT BUY ALL THEIR WATER

Population served Reduced monitoring frequency and location 

Subpart H systems

<500 ..................................... Monitoring may not be reduced. 

500 to 4,999 ......................... 1 TTHM and 1 HAA5 sample per year at different locations or during different quarters if the highest TTHM and 

HAA5 occurred at different locations or different quarters or 1 dual sample per year if the highest TTHM and 

HAA5 occurred at the same location and quarter. 

5,000 to 9,999 ...................... 2 dual sample sets per year; one at the location with the highest TTHM single measurement during the quarter 

that the highest single TTHM measurement occurred, one at the location with the highest HAA5 single measurement during the quarter that the highest single HAA5 measurement occurred. 

10,000 to 24,999 .................. 2 dual sample sets per quarter at the locations with the highest TTHM and highest HAA5 LRAAs.

25,000 to 49,999 .................. 2 dual sample sets per quarter at the locations with the highest TTHM and highest HAA5 LRAAs.

50,000 to 99,000 .................. 4 dual sample sets per quarter at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

100,000 to 499,999 .............. 4 dual sample sets per quarter at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

500,000 to 1,499,999 ........... 6 dual sample sets per quarter at the locations with the three highest TTHM and three highest HAA5 LRAAs. 

1,500,000 to 4,999,999 ........ 6 dual sample sets per quarter at the locations with the three highest TTHM and three highest HAA5 LRAAs. 

>=5,000,000 ......................... 8 dual sample sets per quarter at the locations with the four highest TTHM and four highest HAA5 LRAAs. 

Ground water systems

<500 ..................................... 1 TTHM and 1 HAA5 sample every third year at different locations or during different quarters if the highest 

TTHM and HAA5 occurred at different locations or different quarters or 1 dual sample every third year if the 

highest TTHM and HAA5 occurred at the same location and quarter. 

500 to 9,999 ......................... 1 TTHM and 1 HAA5 sample every year at different locations or during different quarters if the highest TTHM and 

HAA5 occurred at different locations or different quarters or 1 dual sample every year if the highest TTHM and 

HAA5 occurred at the same location and quarter. 

10,000 to 99,000 .................. 2 dual sample sets per year; one at the location with the highest TTHM single measurement during the quarter 

that the highest single TTHM measurement occurred and one at the location with the highest HAA5 single 

measurement during the quarter that the highest single HAA5 measurement occurred. 

100,000 to 1,499,999 ........... 2 dual sample sets per quarter; at the locations with the highest TTHM and highest HAA5 LRAAs. 

≥1,500,000 ........................... 4 dual sample sets per quarter; at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

Systems may remain on reduced 

monitoring as long as the TTHM LRAA 

≤0.040 mg/L and the HAA5 LRAA 

≤0.030 mg/L at each monitoring location 

for systems with quarterly reduced 

monitoring. If the LRAA at any location 

exceeds either 0.040 mg/L for TTHM or 

0.030 mg/L for HAA5 or if the source 

water annual average TOC level, before 

any treatment, exceeds 4.0 mg/L at any 

of the system’s treatment plants treating 

surface water or ground water under the 

direct influence of surface water, the 

system must resume routine monitoring. 

For systems with annual or less frequent 

reduced monitoring, systems may 

remain on reduced monitoring as long 

as each TTHM sample ≤0.060 mg/L and 

each HAA5 sample ≤0.045 mg/L. If the 

annual sample at any location exceeds 

either 0.060 mg/L for TTHM or 0.045 

mg/L for HAA5, or if the source water 

annual average TOC level, before any 

treatment, exceeds 4.0 mg/L at any 

treatment plant treating surface water or 

ground water under the direct influence 

of surface water, the system must 

resume routine monitoring. 

Compliance determination: A PWS is 

in compliance when the annual sample 

or LRAA of quarterly samples is less 

than or equal to the MCLs. If an annual 

sample exceeds the MCL, the system 

must conduct increased (quarterly) 

monitoring but is not immediately in 

violation of the MCL. The system is out 

of compliance if the LRAA of the 

quarterly samples for the past four 

quarters exceeds the MCL. 

2. How Was This Proposal Developed? 

The proposed monitoring 

requirements for the IDSE and Stage 2B 

primarily follow a plant-based approach 

that was adopted from the 1979 TTHM 

Rule and the Stage 1 DBPR. This 

approach includes differences in 

monitoring frequency between surface 

water and ground water sources, and 

between large and small systems. 

However, the proposed monitoring 

requirements differ from Stage 1 DBPR 

requirements in certain areas, including 

(a) sampling intervals for quarterly 

monitoring, (b) reduced monitoring 

frequency, (c) different sampling 

locations by disinfectant type (for the 

IDSE), and (d) population-based 

monitoring requirements for certain 

consecutive systems. This subsection

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49601

presents the basis for these 

requirements. 

a. Sampling intervals for quarterly 

monitoring. Today’s proposal requires 

systems conducting routine quarterly 

monitoring to sample approximately 

every 90 days. This provision modifies 

the approach used in the 1979 TTHM 

rule and the Stage 1 DBPR, which 

requires certain systems to conduct 

monitoring based on calendar quarters. 

When systems are required to monitor 

based on calendar quarters, systems can 

choose to cluster samples during times 

of the year when DBP levels are lower 

(DBPs tend to form more slowly in 

colder water temperatures). For 

example, a system could sample in 

December (at the end of the fourth 

quarter) and again in January (at the 

beginning of the first quarter) when the 

water is the coldest and sample in April 

(at the beginning of the second quarter) 

and September (at the end of the third 

quarter) at either end of the hot summer 

months. 

To address the concern with systems 

not sampling during months with the 

highest DBP levels, EPA is proposing to 

require systems to monitor during the 

month of highest historical DBP 

concentrations and require that systems 

monitor approximately every 90 days. 

EPA believes that this new monitoring 

strategy will improve public health 

protection because systems will be 

required to monitor when high DBP 

levels are expected, and the LRAA will 

better reflect actual exposure during the 

year. 

b. Reduced monitoring frequency.

Today’s proposal contains provisions 

allowing reduced routine monitoring 

when certain criteria are fulfilled 

(shown in Table V–5 and V–7). EPA 

believes that more stringent standards 

are necessary to ensure public health 

protection when systems reduce the 

frequency of their DBP monitoring. 

Under the reduced monitoring 

provisions, systems must collect 

samples during the months of highest 

DBP occurrence. For systems sampling 

annually under the reduced monitoring 

provisions, EPA believes that public 

health protection would likely be 

ensured throughout the year if the high 

values are known to be below 0.060 mg/

L for TTHM and 0.045 mg/L for HAA5. 

Systems monitoring every three years 

must maintain single samples under 

0.040 mg/L for TTHM and 0.030 mg/L 

for HAA5 to ensure adequate public 

health protection over the course of the 

three years. 

c. Different IDSE sampling locations 

by disinfectant type. Today’s proposal 

contains different requirements for IDSE 

monitoring locations based on the 

disinfectant residual used in the 

distribution system. Systems that use 

chloramines are required to select more 

near-entry point monitoring sites for the 

IDSE than chlorinated systems of 

similar size and source water type. This 

is due to differences in DBP formation 

under chloraminated and chlorinated 

conditions. Chloramine residuals are 

more stable than chlorine residuals and 

do not react as readily with organic 

compounds in the water. Based on 

evaluation of Information Collection 

Rule data, DBP concentrations in 

chloraminated systems vary less 

throughout the distribution system than 

in chlorinated systems. HAA5, in 

particular, can peak at or near the entry 

point to the distribution system in a 

chloraminated system (USEPA 2003o). 

d. Population-based monitoring 

requirements for certain consecutive 

systems. While the Advisory Committee 

recommended basic principles for how 

consecutive systems should be 

regulated, it did not recommend how 

EPA should explicitly address some of 

the unique situations that pertain to 

consecutive systems. In this regard, 

consecutive systems that purchase all of 

their finished water year-round are 

different than other systems in that they 

do not have a treatment plant. Rather, 

these systems often receive water from 

multiple wholesale systems or through 

multiple consecutive system entry 

points on a seasonal or intermittent 

basis. Because a plant-based monitoring 

approach (which counts treated water 

distribution system entry points from 

different entities as plants) would be 

very difficult to implement for 

consecutive systems that purchase all of 

their finished water year-round, EPA is 

proposing a population-based approach 

for such systems. 

Under a population-based approach, 

the frequency of monitoring is based on 

the population served and remains the 

same regardless of how many entities 

are providing water to the consecutive 

system at different times of the year. 

The population categories and 

associated monitoring frequencies in 

Tables V–4 and V–6 for IDSE and Stage 

2B routine monitoring reflect EPA’s 

consideration that distribution system 

complexity generally increases as the 

population served grows. Increasing 

distribution system complexity warrants 

more monitoring to represent DBP 

occurrence. 

EPA developed the proposed 

population-based monitoring 

requirements in accordance with certain 

guidelines. These are stated as follows:

—The sampling frequency for surface 

water systems should be greater than 

for ground water systems. The basis 

for this is that, in general, systems 

using surface water or mixed source 

water supplies are likely to 

experience higher and more variable 

DBP occurrence over time than 

systems using ground water 

exclusively. 

—Smaller systems should be allowed to 

monitor less frequently per location 

than larger systems because their 

distribution systems are generally less 

complex and monitoring costs on a 

per capita basis are much higher.

—For systems using surface water, the 

ratio of IDSE sample locations to the 

number of routine sample locations 

required for Stage 2B should be 

approximately 2:1 (consistent with 

Advisory Committee 

recommendations for plant-based 

monitoring). IDSE sampling is 

intended to identify distribution 

system locations with high DBP levels 

and should, therefore, be more 

thorough than routine monitoring. 

—Because ground water systems have 

much less variable DBP levels within 

the distribution system than surface 

water systems (see section IV), a 

smaller number of additional IDSE 

monitoring locations is warranted. 

—Distribution system sampling 

locations should be approximately 

consistent with the proposed plantbased approach as recommended by 

the Advisory Committee. This will 

capture the locations with the high 

TTHM and HAA5 LRAAs identified 

in the IDSE, but also include Stage 1 

compliance locations with high 

TTHM and HAA5 for historical 

tracking.

Consistent with the first two 

guidelines, the proposed populationbased monitoring requirements 

maintain the same monitoring frequency 

per sample location as proposed under 

the plant-based approach. The following 

subsection provides further discussion 

of the population-based approach as it 

might apply to all systems. 

3. Request For Comment 

EPA is requesting comments on the 

proposed monitoring requirements. This 

subsection begins with a list of specific 

questions related to the proposed 

requirements for IDSE and Stage 2B 

monitoring. This is followed by a 

discussion of issues associated with 

plant-based monitoring requirements 

and a request for comment on potential 

approaches to address these issues, 

including the extension of populationbased monitoring requirements to all 

systems under the Stage 2 DBPR. 

a. Proposed IDSE and Stage 2B 

monitoring requirements. EPA is

49602 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

requesting comment on a number of 

specific aspects of the proposed 

monitoring requirements.

—Should EPA require all systems that 

are on reduced monitoring to revert to 

routine monitoring during the IDSE 

monitoring period to allow for more 

data to be evaluated in the IDSE 

report to better select Stage 2B 

monitoring locations? Or should EPA 

require a system to be on routine 

monitoring during the IDSE 

monitoring period in order to be 

eligible for an IDSE waiver? What 

limitations, if any, should EPA put on 

system eligibility for an IDSE waiver? 

—Should EPA require different IDSE 

monitoring locations for subpart H 

systems based on the residual 

disinfectant (chlorine or chloramines) 

in light of the possible difficulties for 

implementation and data 

management? Should EPA specify 

monitoring locations in the rule 

language for samples intended to 

represent exposure for people in highrise buildings? Should monitoring 

location selection be addressed in 

guidance? Where should these 

locations be so that they are truly 

representative of the levels of DBPs in 

water actually being consumed in 

these kinds of structures? 

—Is a population-based monitoring 

approach (instead of a plant-based 

monitoring approach) for consecutive 

systems that purchase all of their 

finished water year-round appropriate 

and, if so, is the population-based 

approach proposed today adequate?

EPA solicits comment on the 

significance of monitoring and 

implementation issues such as common 

aquifer determinations, consecutive 

system entry point determinations, 

seasonal plants, and monitoring 

inequities, and whether the proposed 

monitoring requirements should be 

modified. EPA also solicits comment on 

modifying the proposed monitoring 

requirements to address these issues, in 

part, with provisions such as the 

following:

—Should EPA set a limit on the 

maximum number of IDSE and 

routine monitoring samples that could 

be required? Should this limit be 

different for systems using ground 

water or surface water or mixed 

systems? For different system size 

categories? What rationale should be 

used to specify maximum sample 

numbers? 

—Should a provision be included that 

would allow States to reduce the 

sampling frequency, beyond those 

currently proposed (i.e., common 

aquifer determinations and low DBP 

levels)? If so, should specific criteria 

for systems to qualify for State 

approval of reduced monitoring be 

specified in the rule? 

—What, if any, criteria should be set by 

which systems with very large 

distribution systems but few plants 

would be required to conduct 

additional IDSE or routine 

monitoring, beyond that currently 

proposed? 

—For subpart H mixed systems, should 

States be given discretion to reduce 

routine compliance monitoring 

samples intended to represent ground 

water sources, since such sources 

typically have lower precursor levels 

and produce lower DBP 

concentrations? 

—Should EPA allow or require systems 

to reallocate plant-based IDSE 

monitoring locations from small 

plants to large plants? From plants 

with better water quality (based on 

expected lower DBP formation) to 

poorer water quality? What criteria 

should be used?

b. Plant-based vs. population-based 

monitoring requirements. The proposed 

monitoring requirements incorporate a 

plant-based approach for all systems 

other than consecutive systems that 

purchase all of their finished water yearround. The plant-based approach was 

adopted from the 1979 TTHM Rule and 

the Stage 1 DBPR and derives from the 

assumption that as systems increase in 

size, they will tend to have more plants 

(with different sources and treatment) 

and increased complexity. This 

warrants increased monitoring to 

represent DBP occurrence in the 

distribution system. 

EPA has identified a number of issues 

related to the use of a plant-based 

monitoring approach under the Stage 2 

DBPR. The following discussion 

presents these issues and solicits 

comment on approaches to address 

them, including the use of populationbased monitoring requirements. 

i. Issues with plant-based monitoring 

requirements. One issue with a plantbased monitoring approach is that it can 

result in disproportionate monitoring 

requirements for systems serving the 

same number of people. This occurs 

because the required number of 

sampling sites increases with the 

number of plants that feed disinfected 

water into a distribution system. 

Consequently, some systems, depending 

upon their size, the number of treatment 

plants, and the nature of their 

distribution system, will be required to 

collect relatively large or small numbers 

of TTHM and HAA5 samples relative to 

their population served. 

Table V–8 reflects EPA estimates of 

the number of plants per system by 

system size category for systems using 

ground water and subpart H systems. 

Subpart H systems include systems that 

use ground water as a source because 

under the proposal, ground water plants 

in subpart H systems are treated as 

surface water plants for purposes of 

determining monitoring requirements. 

While the proposed plant-based 

requirements distinguish sampling 

requirements by three systems sizes 

(<500 people, 500–9999 people, and 

10,000 or more people), Table V–8 

includes additional size categories to 

reflect the potential inequities in 

sampling requirements among differentsized systems.

TABLE V–8.—NUMBER OF TREATMENT PLANTS PER SYSTEM (BASED ON DATA FROM 1995 CWSS (1)) 

Source water type Population served 

No. of systems in 

database 

No. of treatment plants per system 

10th

percentile Median Mean 90thpercentile 

95th

percentile Maximum 

Subpart H ............................ 0–499 ..................... 124 1 1 1.4 2 3 5 

500–4,999 .............. 146 1 1 1.3 2 3 6 

5,000–9,999 ........... 64 1 1 1.7 3 4 6 

10,000–24,999 ....... 59 1 1 2.0 3 4 18 

25,000–49,999 ....... 46 1 1 2.2 4 6 9 

50,000–99,999 ....... 76 1 2 3.4 6 12 34 

100,000–499,999 ... 51 1 2 3.0 5 10 21 

≥500,000 ................ 23 2 4 5.8 10 13 56 

Ground Water ...................... 0–499 ..................... 181 1 1 1.4 3 4 11 

500–9,999 .............. 332 1 1 1.8 3 4 13 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49603

TABLE V–8.—NUMBER OF TREATMENT PLANTS PER SYSTEM (BASED ON DATA FROM 1995 CWSS (1))—Continued

Source water type Population served 

No. of systems in 

database 

No. of treatment plants per system 

10th

percentile Median Mean 90thpercentile 

95th

percentile Maximum 

10,000–99,999 ....... 128 1 4 4.2 9 11 18 

≥100,000 ................ 21 1 3 9.9 31 32 33 

(1) Results from analysis of 1995 CWSS data (Question Q18). The analysis uses a statistical bootstrapping approach to generate the number 

of plants per system. Details of this analysis are described in the 2002 revisions to the Model Systems Report [to be published]. The maximums 

reflect the maximum number of plants per system among the respondents to the 1995 CWSS. Since the 1995 CWSS database only reflects a 

fraction of all the systems in the respective size categories, some systems are likely to have a higher number of plants per system than the 

maximums listed in this table. 

Noteworthy in Table V–8 are the wide 

ranges of number of plants per system 

in the various size categories for both 

ground water and surface water systems 

and, consequently, the wide range of 

potential monitoring implications. Since 

the number of treatment plants directly 

influences the number of samples 

required, systems serving the same 

number of people may have more than 

a 10-fold difference in required 

sampling, depending on the numbers of 

plants in their systems. For example, 

Table V–8 indicates that for ground 

water systems serving at least 10,000 

people, at least 10% of the systems had 

only one treatment plant, while 10% 

(90th percentile) had 10 or more 

treatment plants. 

While Table V–8 does not take into 

account factors that may reduce 

monitoring requirements, such as 

common aquifer determinations, EPA 

believes these data indicate that DBP 

sampling requirements based on the 

number of water treatment plants per 

system may be excessive for many 

systems. This is particularly the case for 

those systems with many ground water 

plants, since their DBP levels are often 

low and relatively stable. 

Conversely, for other systems, such as 

large surface water systems with one 

plant, plant-based monitoring 

requirements may not require enough 

samples to fairly represent DBP 

occurrence in the distribution system. 

For example, under the plant-based 

approach, a system with only one plant 

serving 100,000—499,000 people would 

have the same sampling requirements as 

a system with one plant serving 11,000 

people. The larger of these two systems 

is likely to have much more pipe length 

and other complex factors influencing 

DBP formation (such as number of 

storage tanks or booster chlorination 

points in the distribution system). Also, 

systems with multiple plants must take 

the same number of samples per plant, 

even if one plant provides a much 

higher percentage of the water than 

another. 

Another issue with plant-based 

monitoring requirements is when plants 

or consecutive system entry points are 

operated seasonally or intermittently. A 

monitoring location that represents a 

plant or entry point during a monitoring 

period when it is in operation will not 

be representative when that plant or 

entry point it is not in operation. 

A third issue is requirements for 

consecutive systems. For consecutive 

systems that also treat source water to 

produce finished water, each 

consecutive system entry point is 

considered a treatment plant for the 

purpose of determining monitoring 

requirements, except when the State 

allows multiple entry points to be 

treated as a single plant (see section V.C. 

for further discussion). Each entry point 

is treated as a separate plant to 

recognize different source waters and 

treatment (resulting in different DBP 

levels) from the wholesale system(s) and 

the treatment plants(s) operated by the 

consecutive system. However, under 

this plant-based approach, State 

determinations of monitoring 

requirements for consecutive systems 

will be complicated, especially in large 

combined distribution systems with 

many connections between systems. 

ii. Approaches to addressing issues 

with plant-based monitoring. EPA is 

requesting comment on two approaches 

to address the issues with plant-based 

monitoring requirements described in 

this subsection. One approach is to keep 

the proposed plant-based monitoring 

approach and add new provisions to 

address specific concerns. Another 

approach is to base monitoring 

requirements on population served in 

lieu of the number of water treatment 

plants per system. The following 

paragraphs describe each approach. 

EPA could maintain a plant-based 

monitoring approach and try to address 

the related issues described in this 

subsection through modifying the 

proposed monitoring requirements with 

provisions like the following:

—Set a limit on the maximum number 

of IDSE and routine monitoring 

samples that could be required. EPA 

believes that this limit should be 

different for systems using ground 

water or surface water or mixed 

systems and for different system size 

categories. However, the Agency has 

not developed a rationale to specify 

maximum sample numbers for 

specific system categories. 

—Include a provision that would allow 

States to reduce the required number 

of samples for reasons other than 

those currently proposed (i.e., 

common aquifer determinations and 

low DBP levels). EPA would have to 

develop specific criteria in the rule for 

systems to qualify for State approval 

of reduced monitoring. For example, 

in subpart H mixed systems, States 

could be given discretion to reduce 

routine compliance monitoring for 

ground water sources, since such 

sources typically have lower DBP 

concentrations. 

—Develop criteria by which systems 

with very large distribution systems 

but with few plants would be required 

to conduct additional IDSE or routine 

monitoring in order to better 

characterize DBP exposure throughout 

the distribution system.

These provisions would allow for 

some issues to be addressed, but would 

make implementation complex and 

could add a significant burden to States. 

An alternative approach to addressing 

the issues with plant-based monitoring 

requirements is to apply populationbased monitoring requirements to all 

systems. Under a population-based 

monitoring approach, the total system 

population served and the source water 

type would determine the number of 

IDSE and routine monitoring samples 

taken. Monitoring requirements would 

not be based on the number of plants 

per system or consecutive system entry 

points. States would not be required to 

make common aquifer determinations or 

address whether plants are combined 

into a single pipe prior to entering the 

distribution system. 

Proposed population-based 

monitoring requirements for

49604 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

consecutive systems that purchase all 

their finished water year-round are 

shown in Tables V–4, V–6, and V–7. 

Also, the proposed rule language in 

subparts U and V contains requirements 

for population-based monitoring similar 

to what might be required for all 

systems. EPA believes that through 

using a broader array of system size 

categories than under the plant-based 

approach, population-based monitoring 

could result in an equitable 

proportioning of DBP sampling 

requirements. Tables V–9 and V–10 

compare the proposed numbers of 

sampling locations per system under a 

population-based approach with a 

plant-based approach, using the median 

and mean number of plants per system 

given in Table V–8 for each of the size 

categories. For surface water systems, 

the median provides a better indicator 

of the typical number of required 

sampling locations under the plantbased approach because it is much less 

sensitive to systems with a very large 

number of plants.

TABLE V–9.—COMPARISON OF MONITORING LOCATIONS PER SYSTEM UNDER IDSE FOR PLANT-BASED AND POPULATIONBASED APPROACHES

Source water type Population size category 

Number 

of sampling 

periods 

Plant-based Population-based 

Number of 

monitoring locations per 

plant 1

Number of monitoring locations per 

system 

Number of monitoring locations 

per system 3

Based on median number of 

plants per 

system 2

Based on mean 

number of plants 

per system 2

Subpart H ............................ 0–499 ............................. 2 2 2 3 2 

500–4,999 ...................... 4 2 2 3 2 

5,000–9,999 ................... 4 2 2 3 4 

10,000–24,999 ............... 6 8 8 16 8 

25,000–49,999 ............... 6 8 8 18 12 

50,000–99,999 ............... 6 8 16 27 16 

100,000–499,999 ........... 6 8 16 24 24 

500,000–1,499,000 ........ 32 

1,500,000–4,999,999 ..... 6 8 32 46 40 

≥5,000,000 ..................... 48 

Ground Water ...................... 0–499 ............................. 2 2 2 2 2 

500–9,999 ...................... 2 2 2 4 2 

10,000–99,999 ............... 4 2 8 9 6 

100,000–499,999 ........... 4 2 6 20 8 

≥500,000 ........................ 12 

1From Table V–5. 2 Calculated from the number of locations per plant multiplied by number of plants per system (Table V–8). 3From Table V–4. 

TABLE V–10.—COMPARISON OF ROUTINE MONITORING LOCATIONS PER SYSTEM UNDER STAGE 2B FOR PLANT-BASED

AND POPULATION-BASED APPROACHES

Source water type Population size category 

Frequency 

of 

monitoring 

Plant-based Population-based 

Number of 

monitoring locations per 

plant 1

Number of monitoring locations per 

system 

Number of monitoring locations 

per system 3

Based on median number of 

plants per 

system 2

Based on mean 

number of plants 

per system 2

Subpart H ............................ 0–499 ............................. 1 1 1 1 2 

500–4,999 ...................... 4 2 2 3 2 

5,000–9,999 ................... 4 2 2 3 2 

10,000–24,999 ............... 4 4 4 8 4 

25,000–49,999 ............... 4 4 4 9 6 

50,000–99,999 ............... 4 4 8 14 8 

100,000–499,999 ........... 4 4 8 12 12 

500,000–1,499,000 ........ 16 

1,500,000–4,999,999 ..... 4 4 16 23 20 

≥5,000,000 ..................... 24 

Ground Water ..................... 0–499 ............................. 1 1 1 1 2 

500–9,999 ...................... 1 2 2 4 2 

10,000–99,999 ............... 4 2 8 9 4 

100,000–499,999 ........... 4 2 6 20 6 

≥500,000 ........................ 8 

1From Table V–5. 2 Calculated from the number of locations per plant multiplied by number of plants per system (Table V–8). 3From Table V–6. 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49605

Under the population-based 

approach, the number of required 

sampling locations for systems of 

different size and source water type 

approximates the number of sampling 

locations that would be required for the 

majority of systems under the plantbased approach. However, systems in 

the tail ends of the distribution of 

number of plants per system would be 

required to take more or fewer samples 

than under the plant-based approach. 

EPA used the median number of plants 

in a given size category as the primary 

basis for establishing the number of 

monitoring locations for the populationbased approach. 

EPA adjusted the number of sampling 

locations for systems in population sizes 

25,000 to 49,999, 100,000–499,999, and 

greater than 1,500,000 to provide a more 

even upward trend in proportion to 

population increase. Consistent with the 

plant-based approach, ground water 

systems serving 10,000 people or greater 

would be required to sample at 

approximately 1⁄3 to 1⁄2 the frequency 

required for surface water systems 

under the population-based approach. 

EPA suggests that the monitoring 

frequencies for the IDSE and Stage 2B 

compliance proposed for consecutive 

systems that purchase all of their 

finished water year-round (as presented 

in Tables V–4 and V–6) are appropriate 

for all systems if a population-based 

approach were used in lieu of a plantbased approach in the final rule. EPA 

believes that the population-based 

approach would ensure more equal and 

rational monitoring requirements among 

systems serving similar populations 

than the plant-based approach does, 

while providing generally improved 

representation of DBP occurrence 

throughout the distribution system. 

Such an approach would simplify 

implementation and reduce 

transactional costs to States by 

facilitating determination of the number 

of sampling locations. 

To further evaluate the potential 

implications of monitoring under the 

population-based approach, EPA has 

prepared an economic analysis 

addressing monitoring impacts using 

the population-based approach 

(Economic Analysis for the Stage 2 

DBPR, EPA 2003i) and guidance on how 

plant-based monitoring requirements 

would be affected if a population-based 

approach were used instead (Draft IDSE 

Guidance Manual, EPA 2003j). 

EPA requests comments on alternative 

DBP monitoring requirements that are 

population-based versus plant-based; 

specifically on the merits of a 

population-based monitoring approach 

for all systems for the purpose of 

addressing the issues raised in this 

section. Specifically:

—Should alternative system size 

categories be specified under the 

suggested population-based 

approach? 

—What potential issues might be unique 

for a population-based monitoring 

approach and how might they be 

addressed? 

—Should alternative numbers of 

monitoring locations or frequencies be 

required in the IDSE or for Stage 2B 

monitoring? 

—Are reduced monitoring requirements 

adequate to ensure continued 

protection relative to the MCL? 

—What are the transition costs and 

issues associated with moving from a 

plant-based to a population based 

approach and how might they be 

addressed? 

J. Compliance Schedules 

1. What is EPA Proposing? 

Today’s proposed rule establishes 

compliance deadlines for public water 

systems to implement the requirements 

in this rulemaking. EPA is proposing a 

phased strategy for MCLs and 

simultaneous compliance with the 

LT2ESWTR consistent with the 

recommendation of the M-DBP 

Advisory Committee and to comply 

with SDWA requirements for risk 

balancing. Central to the determination 

of these deadlines is the principle of 

simultaneous compliance between the 

Stage 2 DBPR and the LT2ESWTR, 

which will ensure continued microbial 

protection as systems implement 

changes to decrease DBP levels and 

minimize risk-risk tradeoffs. 

IDSE schedule. Subpart H and ground 

water systems covered by today’s 

proposed rule that serve a population of 

10,000 or more must submit the results 

of their IDSE to the primacy agency two 

years after rule promulgation. In 

addition, wholesale or consecutive 

systems serving fewer than 10,000 that 

are part of a combined distribution 

system with at least one system serving 

≥10,000 must meet this same schedule. 

These systems must begin IDSE 

monitoring early enough to collect and 

analyze 12 months of data and prepare 

an IDSE report, which includes 

recommendations for Stage 2B 

monitoring locations (see section V.H). 

Subpart H and ground water systems 

covered by today’s proposed rule that 

serve a population of fewer than 10,000 

(except those noted before) must submit 

the results of their IDSE to the primacy 

agency four years after rule 

promulgation. These systems must 

begin IDSE monitoring early enough to 

collect and analyze the data and prepare 

the IDSE report. 

Stage 2A schedule. All systems must 

comply with the Stage 2A MCLs for 

TTHM and HAA5 three years after rule 

promulgation. 

Stage 2B schedule. Systems required 

to submit an IDSE report due two years 

after the rule is promulgated must 

comply with Stage 2B six years after 

rule promulgation. Subpart H systems 

required to submit IDSE reports four 

years after rule promulgation and 

required to do Cryptosporidium

monitoring under the LT2ESWTR must 

comply with Stage 2B 8.5 years after 

rule promulgation. Small systems not 

required to Cryptosporidium monitoring 

must be in compliance with Stage 2B 

7.5 years after rule promulgation. Figure 

V–2 contains several examples of how 

to determine IDSE and Stage 2B 

compliance dates.

FIGURE V–2. SCHEDULE EXAMPLES

—Wholesale system (pop. 64,000) with three consecutive systems (pops. 21,000; 15,000; 5,000): 

—IDSE report due for all systems two years after promulgation since wholesale system serves at least 10,000 

—Stage 2B compliance beginning six years after promulgation for all systems 

—Wholesale system (pop. 4,000) with three consecutive systems (pops. 21,000; 5,000; 5,000): 

—IDSE report due for all systems two years after promulgation since one consecutive system in combined distribution system serves at 

least 10,000 

—Stage 2B compliance beginning six years after promulgation for all systems 

—Wholesale system (pop. 4,000) with three consecutive systems (pops. 8,000; 5,000; 5,000): 

—IDSE report due for all systems four years after promulgation since no system in combined distribution system exceeds 10,000 (even 

though total population exceeds 10,000) 

—Stage 2B compliance beginning 7.5 years after promulgation if no Cryptosporidium monitoring under the LT2ESWTR is required or beginning 8.5 years after promulgation if Cryptosporidium monitoring under the LT2ESWTR is required 

49606 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

2. How Did EPA Develop This Proposal? 

EPA is proposing provisions for 

simultaneous rule compliance with the 

LT2ESWTR to maintain a balance 

between DBP and microbial risks. 

Simultaneous compliance was 

mandated by the 1996 SDWA 

Amendments which require that EPA 

‘‘minimize the overall risk of adverse 

health effects by balancing the risk from 

the contaminant and the risk from other 

contaminants, the concentrations of 

which may be affected by the use of a 

treatment technique or process that 

would be employed to attain the 

maximum contaminant level’’ (Sec. 

1412(b)(5)(B)(i)). 

If systems were required to comply 

with the Stage 2 DBPR prior to the 

LT2ESWTR, systems could lower their 

disinfectant dose or switch to a less 

effective disinfectant in an attempt to 

decrease DBP levels. This practice could 

leave segments of the population 

exposed to greater microbial risks. 

Therefore, simultaneous compliance 

was a consensus recommendation of the 

Stage 2 M-DBP Advisory Committee to 

ensure that systems would not 

compromise microbial protection while 

attempting to meet more stringent DBP 

requirements. 

The Advisory Committee supported 

the Initial Distribution System 

Evaluation, as discussed in section V.H, 

and EPA is proposing an IDSE schedule 

consistent with the Advisory 

Committee’s recommendations, in 

which systems are required to submit 

their IDSE reports to the State either two 

or to four years following rule 

promulgation. The Advisory Committee 

recommended this to allow enough time 

for the State to review (and revise, if 

necessary) systems’ recommendations 

for Stage 2B monitoring locations and to 

allow systems three years after 

completion of the State review to 

comply with Stage 2B MCLs as LRAAs 

at Stage 2B monitoring locations. 

This schedule requires systems 

serving ≥10,000 people and smaller 

wholesale and consecutive systems that 

are part of a combined distribution 

system that includes at least one system 

serving ≥10,000 to complete IDSE 

monitoring and prepare and submit the 

IDSE report two years after the rule is 

finalized. This requirement for 

wholesale systems and consecutive 

systems serving fewer than 10,000 that 

are part of a combined distribution 

system with at least one system serving 

at least 10,000 to conduct an ‘‘early 

IDSE’’ allows the wholesale system to be 

aware of compliance challenges facing 

the consecutive system and to 

implement treatment plant capital and 

operational improvements as necessary 

to ensure compliance. The Advisory 

Committee and EPA both recognized 

that DBPs, once formed, are difficult to 

remove and are generally best addressed 

by treatment plant improvements. 

While this schedule allows for 

systems to have the three years to 

comply with Stage 2B following State 

review of the IDSE report, it begins prior 

to States being required to obtain 

primacy to implement the IDSE. States 

have two years from promulgation to 

adopt and implement new regulations 

and may request a two year extension. 

While EPA is preparing to support 

implementation of those IDSE 

requirements that must be completed 

prior to States achieving primacy, 

several States have expressed concern 

about EPA providing guidance and 

reviewing reports from systems that the 

State has permitted, inspected, and 

worked with for a long time. These 

States believe that their familiarity with 

the systems enables them to make the 

best decisions to implement the rule 

and protect public health. 

As specific rule requirements were 

developed and implementation 

schedules and resource burdens 

determined, States also expressed 

concerns about the challenges that early 

implementation posed. In response to 

these concerns, EPA has developed 

several alternatives to the IDSE schedule 

and provisions that may meet the goals 

of the IDSE, but allow for greater State 

involvement, lower implementation 

burden, and no delay of the public 

health protection assured by compliance 

with Stage 2B. 

The first, the ‘‘Alternative IDSE’’

option, would delay the schedule for 

each IDSE requirement for two years. 

Since the compliance date for Stage 2B 

would not be delayed, systems would 

need to implement changes necessary 

for compliance on a much shorter 

schedule. 

The second, the ‘‘Concurrent 

Compliance Monitoring’’ option, would 

eliminate the IDSE but require 

compliance monitoring at an increased 

number of sites during the first year of 

compliance monitoring as a way to 

identify sites with high DBP levels. This 

option would reduce government 

oversight and management and, as with 

other rules, leave compliance 

determinations and preparations to 

individual systems (with guidance 

available from States). In addition to 

compliance monitoring at Stage 1 DBPR 

compliance monitoring sites during the 

first year under Stage 2B, systems would 

also monitor at additional compliance 

monitoring sites equal in number to the 

IDSE requirement and selected using the 

same criteria that systems use to select 

IDSE monitoring sites. Following one 

year of concurrent compliance 

monitoring, the system would select 

routine Stage 2B compliance monitoring 

locations using a protocol similar to the 

one used to recommend Stage 2B 

compliance monitoring locations in the 

IDSE report. 

Neither alternative would extend the 

compliance dates for either Stage 2A or 

Stage 2B. As with the proposed IDSE, 

systems would be eligible for the 40/30 

certification approach if all TTHM and 

HAA5 compliance monitoring results in 

the two years prior to the effective date 

were below 0.040 mg/L and 0.030 mg/

L, respectively. States would be able to 

grant very small system waivers to 

systems serving <500 with a State 

finding that Stage 1 DBPR compliance 

monitoring locations sites are adequate 

to represent both high TTHM and high 

HAA5 concentrations. Table V–11 

contains a comparison of the proposed 

IDSE schedule and the schedules for the 

alternatives.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49607

TABLE V–11.—COMPARISON OF IDSE AND IDSE ALTERNATIVE SCHEDULES

[Dates in italics are not in today’s proposed rule, but reflect EPA’s recommendation and guidance] 

Requirement 1 Today’s proposal ‘‘Alternative IDSE’’

option ‘‘Concurrent compliance monitoring’’ option 

IDSE start date for systems ≥10,000 ...............

IDSE start date for systems <10,000 ...............

IDSE report due for systems ≥10,000 .............

IDSE report due for systems <10,000 .............

State review of IDSE report complete for systems ≥10,000.

State review of IDSE report complete for systems <10,000.

0.5 years after 

publication.

2.5 years after 

publication.

2 years after 

publication.

4 years after 

publication.

3 years after 

publication.

4.5 years after publication.

2.5 years after 

publication 

4.5 years after 

publication 

4 years after 

publication 

6 years after 

publication 

5 years after 

publication 

6.5 years after publication 

Requirement is for system to conduct concurrent compliance monitoring (generally 

equal to number of samples required under 

Stage 1 plus number under IDSE) during 

first year of compliance monitoring. Based 

on results in first year, system would identify routine compliance monitoring locations 

using a procedure similar to that in IDSE 

report and begin routine monitoring. 

Stage 2B compliance for systems ≥10,000 ..... 6 years after publication 2

Stage 2B compliance for systems <10,000 ..... 7.5 years after publication if system is not required to conduct Cryptosporidium monitoring; 8.5 

years after publication if system required to conduct Cryptosporidium monitoring 2

1Systems serving ≥10,000 also include wholesale systems and consecutive systems serving <10,000 that are part of a combined distribution 

system in which at least one system serves ≥10,000. 2State may grant up to two additional years for capital improvements necessary to comply. 

3. Request for Comments 

EPA requests comments on today’s 

proposed compliance schedules. 

Specifically:

—Should EPA promulgate an alternative 

approach to the IDSE recommended 

in section V.H. that achieves the same 

goal of identifying Stage 2B 

compliance monitoring locations and 

does not delay compliance with Stage 

2B MCLs, but allows for the States to 

receive primacy and be more involved 

in IDSE implementation? Do either 

the ‘‘Alternative IDSE’’ option or the 

‘‘Concurrent Compliance Monitoring’’

option achieve this goal? Does one 

achieve the goal better than the other? 

Why? Are there either changes to 

these alternatives or other alternatives 

not presented that achieve this goal? 

—Should EPA allow small consecutive 

systems to meet Stage 2B compliance 

deadlines corresponding to their size 

(and later than the deadlines for their 

wholesale system) provided they 

complete their IDSE on the same 

schedule as the wholesale system and 

provided their water quality does not 

affect the water quality of any other 

system? 

K. Public Notice Requirements 

1. What is EPA Proposing? 

SDWA section 1414(c) requires PWSs 

to provide notice to their customers for 

certain violations or in other 

circumstances. EPA’s public notification 

rule was published on May 4, 2000 (65 

FR 25982), and is codified at 40 CFR 

141.201–141.210 (Subpart Q). Today’s 

proposal does not alter the existing 

TTHM and HAA5 health effects 

language that is required in most public 

notices under Subpart Q. Because of the 

uncertainties in the health data 

discussed in section III of today’s 

document, EPA is not proposing to 

include information about reproductive 

and developmental health effects in 

public notices at this time. 

2. Request for Comments 

EPA requests comment on the 

proposed public notification 

requirements, including whether 

information about the possible 

reproductive or fetal development 

effects that may be associated with high 

levels of DBPs should be provided. 

L. Variances and Exemptions 

States may grant variances in 

accordance with sections 1415(a) and 

1415(e) of the SDWA and EPA’s 

regulations. States may grant 

exemptions in accordance with section 

1416 of the SDWA and EPA’s 

regulations. 

1. Variances 

The SDWA provides for two types of 

variances—general variances and small 

system variances. Under section 

1415(a)(1)(A) of the SDWA, a State that 

has primary enforcement responsibility 

(primacy), or EPA as the primacy 

agency, may grant general variances 

from MCLs to those public water 

systems of any size that cannot comply 

with the MCLs because of 

characteristics of the water sources. A 

variance may be issued to a system on 

condition that the system install the best 

technology, treatment techniques, or 

other means that EPA finds available 

and based upon an evaluation 

satisfactory to the State that indicates 

that alternative sources of water are not 

reasonably available to the system. At 

the time this type of variance is granted, 

the State must prescribe a compliance 

schedule and may require the system to 

implement additional control measures. 

Furthermore, before EPA or the State 

may grant a general variance, it must 

find that the variance will not result in 

an unreasonable risk to health to the 

public served by the public water 

system. In this proposed rule, EPA is 

specifying BATs for general variances 

under section 1415(a) (see section V.F). 

Section 1415(e) authorizes the 

primacy agency to issue variances to 

small public water systems (those 

serving fewer than 10,000 people) where 

the primacy agent determines (1) that 

the system cannot afford to comply with 

an MCL or treatment technique and (2) 

that the terms of the variances will 

ensure adequate protection of human 

health (63 FR 1943–57; USEPA 1998d). 

These variances may only be granted 

where EPA has determined that there is 

no affordable compliance technology 

and has identified a small system 

variance technology under section 

1412(b)(15) for the contaminant, system 

size and source water quality in 

question. As discussed below, small 

system variances under section 1415(e) 

are not available because EPA has 

determined that affordable compliance 

technologies are available. 

The 1996 Amendments to the SDWA 

identify three categories of small public 

water systems that need to be addressed: 

(1) Those serving a population of 3301–

10,000; (2) those serving a population of 

500–3300; and (3) those serving a 

population of 25–499. The SDWA 

requires EPA to make determinations of 

available compliance technologies and,

49608 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

1EPA is currently receiving input from a National 

Drinking Water Advisory Council (NDWAC). This 

process is expected to conclude in the fall of 2003 

with a report that will be sent by the NDWAC. EPA 

has also received a report from the Science 

Advisory Board’s Environmental Economics 

Advisory Committee on its review of the nationallevel affordability criteria (USEPA 2002c). One of 

the charges given to both groups was to evaluate the 

process used by EPA to adjust the baseline water 

bills to account for costs attributable to regulations 

promulgated after 1996. Because the Stage 2 DBPR 

affordability analysis is being conducted before EPA 

can complete a comprehensive reassessment of 

affordability, today’s estimate for the increase to the 

average water bill to account for regulations after 

1996 reflects existing Agency affordability criteria 

and methodology. This estimate may change in the 

future.

if needed, variance technologies for 

each size category. A compliance 

technology is a technology that is 

affordable and that achieves compliance 

with the MCL and/or treatment 

technique. Compliance technologies can 

include point-of-entry or point-of-use 

treatment units. Variance technologies 

are only specified for those system size/

source water quality combinations for 

which there are no listed compliance 

technologies. 

EPA has completed an analysis of the 

affordability of DBP control 

technologies for each of the three size 

categories. Based on this analysis, 

multiple affordable compliance 

technologies were found for each of the 

three system sizes (USEPA 2003i) and 

therefore variance technologies were not 

identified for any of the three size 

categories. The analysis was consistent 

with the methodology used in the 

document ‘‘National-Level Affordability 

Criteria Under the 1996 Amendments to 

the Safe Drinking Water Act’’ (USEPA 

1998g) and the ‘‘Variance Technology 

Findings for Contaminants Regulated 

Before 1996’’ (USEPA 1998h). 

2. What Are the Affordable Treatment 

Technologies for Small Systems? 

The treatment trains considered and 

predicted to be used in EPA’s 

compliance forecast for systems serving 

under 10,000 people, are listed in Table 

V–12.

TABLE V–12.—TECHNOLOGIES CONSIDERED AND PREDICTED TO BE USED IN COMPLIANCE TECHNOLOGY FORECAST FOR

SMALL SYSTEMS 1

SW water plants GW water plants 

• Switching to chloramines as a residual disinfectant .............................

• Chlorine dioxide (Not for systems serving fewer than 100 people) .....

• UV .........................................................................................................

• Ozone (not for systems serving fewer than 100 people) .....................

• Micro-filtration/Ultra-Filtration 2 ..............................................................

• GAC20 2 ................................................................................................

• GAC20 + Advanced disinfectants .........................................................

• Membranes (Micro-Filtration/Ultra-Filtration + Nanofiltration) ...............

• Switching to chloramines as a residual disinfectant 

• UV 

• Ozone (not for systems serving fewer than 100 people) 2

• GAC20 2

• Nanofiltration 2

1Based on exhibits 6.8a and 6.8b in Economic Analysis for the proposed Stage 2 DBPR (USEPA 2003i) 

2 Italicized technologies are those predicted to be used in the compliance forecast. 

The household costs for these 

technologies were compared against the 

national-level affordability criteria to 

determine the affordable treatment 

technologies. The Agency’s nationallevel affordability criteria were 

published in the August 6, 1998 Federal 

Register (USEPA 1998g). In this 

document, EPA discussed the procedure 

for affordable treatment technology 

determinations for the contaminants 

regulated before 1996.

The following section provides a 

description of how EPA derived the 

national-level affordability criteria 

pertinent to this rule. First, EPA 

calculated an ‘‘affordability threshold’’

(i.e., the total annual household water 

bill that would be considered 

affordable). The total annual water bill 

includes costs associated with water 

treatment, water distribution, and 

operation of the water system. In 

developing the threshold of 2.5% 

median household income, EPA 

considered the percentage of median 

household income spent by an average 

household on comparable goods and 

services and on cost comparisons with 

other risk reduction activities for 

drinking water such as households 

purchasing bottled water or a home 

treatment device. The complete 

rationale for EPA’s selection of 2.5% as 

the affordability threshold is described 

in ‘‘Variance Technology Findings for 

Contaminants Regulated Before 1996’’

(USEPA 1998h). 

The Variance Technology Findings 

document also describes the derivation 

of the baselines for median household 

income, annual water bills, and annual 

household consumption. Data from the 

Community Water System Survey 

(CWSS) were used to derive the annual 

water bills and annual water usage 

values for each of the three small system 

size categories. The data on zip codes 

were used with the 1990 Census data on 

median household income to develop 

the median household income values 

for each of the three small-system size 

categories. The median householdincome values used for the affordable 

technology determinations are not based 

on the national median income. The 

value for each size category is a national 

median income for communities served 

by small water systems within that 

range. Table V–13 presents the baseline 

values for each of the three small-system 

size categories. Annual water bills are 

based on 1995 estimates (USEPA 1998h) 

and adjusted upward for anticipated 

costs attributed to new drinking water 

regulations since 1995, i.e., the IESWTR, 

Stage 1 DBPR, Filter Backwash 

Recycling Rule, Arsenic Rule, 

LT1ESWTR, Public Notification Rule, 

and Consumer Confidence Rule.1

Median household income estimates are 

based on estimates made in 1995 

(USEPA 1998h) and adjusted upward 

for inflation to represent 2000 incomes 

(USEPA 2003i).

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49609

TABLE V–13.—BASELINE VALUES FOR SMALL SYSTEMS CATEGORIES AND AVAILABLE EXPENDITURE MARGIN FOR

AFFORDABLE TECHNOLOGY DETERMINATIONS

System size category (pop. served) 

Annual HH 

consumption 

(1000 gallons/

yr) 

Median 

HH income ($) 

2.5% median HH 

income(s) 

Current annual 

water bills

($/yr) 

Available expenditure margin ($/hh/year) 

25–500 ............................................................................................. 72 35,148 878 290 588 

501–3,300 ........................................................................................ 74 30,893 772 230 542 

3,301–10,000 ................................................................................... 77 31,559 789 219 570 

For each size category, the threshold 

value was determined by multiplying 

the median household income by 2.5 

percent. The annual household water 

bills were subtracted from this value to 

obtain the available expenditure margin. 

Projected treatment costs were 

compared against the available 

expenditure margin to determine if 

there were affordable compliance 

technologies for each size category. The 

available expenditure margin for the 

three size categories is presented in 

Table V–13. 

The size categories specified in 

SDWA for affordable technology 

determinations are different from the 

size categories typically used by EPA in 

the Economic Analysis. A weighted 

average procedure was used to derive 

design and average flows for the 25–500 

category using design and average flows 

from the 25–100 and 101–500 

categories. A similar approach was used 

to derive design and average flows from 

the 501–1000 and 1001–3300 categories 

for the 501–3300 category. The Variance 

Technology Findings document (USEPA 

1998h) describes this procedure in more 

detail. Table V–14a lists the design and 

average flows for the three size 

categories.

TABLE V–14A.—DESIGN AND AVERAGE DAILY FLOWS USED FOR AFFORDABLE TECHNOLOGY DETERMINATIONS

System size category (population served) Design flow 

(mgd) 

Average flow 

(mgd) 

25–500 ................................................................................................................................................................. 0.058 0.015 

501–3,300 ............................................................................................................................................................ 0.50 0.17 

3,301–10,000 ....................................................................................................................................................... 1.8 0.70 

Capital and operating and 

maintenance costs were derived for each 

treatment technology used in the 

compliance forecast for small systems 

using the flows listed previously and 

the cost equations in the Technology 

and Cost Document (USEPA 2003k). 

Capital costs were amortized using the 

7 percent interest rate preferred by 

Office of Management and Budget 

(OMB) for benefit-cost analyses of 

government programs and regulations 

rather than a 3 percent interest rate. 

The annual system treatment cost in 

dollars per year was converted into a 

rate increase using the average daily 

flow. The annual water consumption 

values listed in Table V–13 were 

multiplied by 1.15 to account for water 

lost due to leaks. Since the water lost to 

leaks is not billed, the water bills for the 

actual water used were adjusted to cover 

this lost water by increasing the 

household consumption. The rate 

increase in dollars per thousand gallons 

used was multiplied by the adjusted 

annual consumption to determine the 

annual cost increase for the household 

for each treatment technology. 

With very few exceptions, the 

household costs for all predicted 

compliance technologies in Table V–12 

are below the available expenditure 

margin. The only technology that was 

predicted to be used in the compliance 

forecast for the Stage 2 DBPR and that 

costs slightly more than the available 

expenditure margin is GAC20 (240 day 

carbon replacement) with advanced 

disinfectants for systems serving 500 

people or fewer. As shown in the 

Economic Analysis (USEPA 2003i), 13 

systems (less than 1 percent) among 

systems serving fewer than 500 people 

are predicted to use GAC20 with 

advanced disinfection to comply with 

the proposed Stage 2 DBPR. However, 

alternate affordable technologies are 

available. Thus, EPA believes that 

compliance by these systems will be 

affordable. In some cases, the 

compliance data for these systems under 

the Stage 2 DBPR is the same as under 

the Stage 1 DBPR (because many 

systems serving fewer than 500 people 

will have the same single sampling site 

under both rules); these systems will 

have already installed the necessary 

compliance technology to comply with 

the Stage 1 DBPR. It is also possible that 

less costly technologies such as those 

for which percentage use caps were set 

in the decision tree may actually be 

used to achieve compliance (e.g., 

chloramines, UV). 

As shown in Table V–14b, the cost 

model (USEPA 2003i) predicts that 

households served by very small 

systems will experience household cost 

increases greater than the available 

expenditure margins as a result of 

adding advanced technology for the 

Stage 2 DBPR. This prediction is 

probably overestimated because small 

systems have other compliance 

alternatives available to them besides 

adding treatment. For example, some of 

these systems currently may be operated 

on a part-time basis; therefore, they may 

be able to modify the current 

operational schedule or use excessive 

capacity to avoid installing a costly 

technology to comply with the Stage 2 

DBPR. The system also may identify 

another water source that has lower 

TTHM and HAA5 precursor levels. 

Systems that can identify such an 

alternate water source may not have to 

treat that new source water as intensely 

as their current source, resulting in 

lower treatment costs. Systems may 

elect to connect to a neighboring water 

system. While connecting to another 

system may not be feasible for some 

remote systems, EPA estimates that 

more than 22 percent of all small water 

systems are located within metropolitan 

regions (USEPA 2000c) where distances 

between neighboring systems will not 

present a prohibitive barrier. More 

discussion of household cost increases 

is presented in a later section (Section 

VII) and the Economic Analysis (USEPA 

2003i).

49610 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

EPA is currently reviewing its 

national-level affordability criteria, and 

has solicited recommendations from 

both the NDWAC and the SAB as part 

of this review. If the national-level 

affordability criteria are revised prior to 

promulgation of the final Stage 2 DBPR, 

EPA may reevaluate the affordability of 

the identified small system compliance 

technologies based on the revised 

criteria and may revise its determination 

of whether to list any variance 

technologies as a result. EPA requests 

comment on the application of its 

affordability criteria in this rulemaking 

and on its determination that there are 

affordable small system compliance 

technologies for all three statutory small 

system size categories. 

M. Requirements for Systems To Use 

Qualified Operators 

EPA believes that systems that must 

make treatment changes to comply with 

requirements to reduce microbiological 

risks and risks from disinfectants and 

disinfection byproducts should be 

operated by personnel who are qualified 

to recognize and respond to problems. 

Subpart H systems were required to be 

operated by qualified operators under 

the SWTR (40 CFR 141.70). The Stage 1 

DBPR added requirements for all 

disinfected systems to be operated by 

qualified personnel who meet the 

requirements specified by the State, 

which may differ based on system size 

and type. The rule also required that 

States maintain a register of qualified 

operators (40 CFR 141.130(c)). While the 

proposed Stage 2 DBPR requirements do 

not supercede or modify the 

requirement that disinfected systems be 

operated by qualified personnel, the 

Stage 2 DBPR re-emphasizes the 

important role that qualified operators 

play in delivering safe drinking water to 

the public. States should also review 

and modify, as required, their 

qualification standards to take into 

account new technologies (e.g., 

ultraviolet (UV) disinfection) and new 

compliance requirements (including 

simultaneous compliance and 

consecutive system requirements). 

N. System Reporting and Recordkeeping 

Requirements 

1. Confirmation of Applicable Existing 

Requirements 

Today’s proposed Stage 2 DBPR, 

consistent with the current system 

reporting regulations under 40 CFR 

141.131, requires public water systems 

to report monitoring data to States 

within ten days after the end of the 

compliance period. In addition, systems 

are required to submit the data required 

in § 141.134. These data are required to 

be submitted quarterly for any 

monitoring conducted quarterly or more 

frequently, and within ten days of the 

end of the monitoring period for less 

frequent monitoring. 

2. Summary of Additional Reporting 

Requirements 

EPA proposes that two years after rule 

promulgation, systems serving 10,000 or 

more people (plus consecutive systems 

that are part of a combined distribution 

system with a system serving at least 

10,000) be required to report the results 

of their IDSE to their State, unless the 

State has waived this requirement for 

systems serving fewer than 500. Systems 

are also required to report to the State 

recommended long-term (Stage 2B) 

compliance monitoring sites as part of 

the IDSE report. While the IDSE options 

discussed in section V.J. would delay 

the timing of this requirement, EPA 

believes that the burden would not 

change. 

Beginning three years after rule 

promulgation, systems must report 

compliance with Stage 2A MCLs based 

on LRAAs (0.120 mg/L TTHM and 0.100 

mg/HAA5), as well as continue to report 

compliance with 0.080 mg/L TTHM and 

0.060 mg/L HAA5 as RAAs. Systems 

must report compliance with the Stage 

2B TTHM and HAA5 MCLs (0.080 mg/

L TTHM and 0.060 mg/L HAA5 as 

LRAAs) according to the compliance 

schedules outlined in section V.J. of 

today’s proposal. Reporting for DBP 

monitoring, as described previously, 

will remain generally consistent with 

current public water system reporting 

requirements (§ 141.31 and § 141.134); 

systems will be required to calculate 

and report each LRAA (instead of the 

system’s RAA) and each individual 

monitoring result (as required under the 

Stage 1 DBPR). Systems will also be 

required to consult with the State about 

each peak excursion event no later than 

the next sanitary survey for the system, 

as discussed in section V.E. 

3. Request for Comment 

EPA requests comment on all system 

reporting and recordkeeping 

requirements. 

O. Analytical Method Requirements 

1. What Is EPA Proposing Today? 

The Stage 2 DBPR proposed today 

does not add any new disinfectants or 

disinfection byproducts to the list of 

contaminants currently covered by 

MRDLs or MCLs. However, additional 

methods have become available since 

the analytical methods in the Stage 1 

DBPR were promulgated (USEPA 

1998c). EPA is proposing to add to 40 

CFR 141.131 one method for chlorine 

dioxide and chlorite, one method for 

HAA5 which can also be used to 

analyze for the regulated contaminant 

dalapon, three methods for bromate, 

chlorite, and bromide, one method for 

bromate only, and one method for total


EP18AU03.009</GPH>
Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49611

organic carbon (TOC) and specific 

ultraviolet absorbance (SUVA). One of 

the methods that is currently approved 

for bromate, chlorite, and bromide can 

be used to determine chloride, fluoride, 

nitrate, nitrite, orthophosphate, and 

sulfate, so EPA is proposing to add it as 

an approved method for those 

contaminants in 40 CFR 141.23 and 40 

CFR 143.4. EPA is also proposing to add 

the HAA5 method that includes dalapon 

to 40 CFR 141.24 for dalapon 

compliance monitoring. 

Several of the methods that were 

promulgated with the Stage 1 DBPR 

have been included in publications that 

were issued after December 1998. EPA 

is proposing to approve the use of the 

recently published versions of three 

methods for determining free, 

combined, and total chlorine residuals, 

two methods for total chlorine only, one 

method for free chlorine only, one 

method for chlorite and chlorine 

dioxide, one method for chlorine 

dioxide only, one method for HAA5, 

three methods for TOC and dissolved 

organic carbon (DOC), and one method 

for ultraviolet absorption at 254nm 

(UV 254). EPA is proposing to update the 

citation for one method for bromate, 

chlorite, and bromide. 

EPA is also proposing to standardize 

the HAA5 sample holding times and the 

bromate sample preservation procedure 

and holding time. EPA is clarifying 

which methods are approved for 

magnesium hardness determinations in 

40 CFR 141.131 and 40 CFR 141.135. 

Analytical methods that are proposed 

for approval or for which changes are 

proposed in today’s rule are 

summarized in Table V–15 and are 

described in more detail later in this 

section.

TABLE V–15.—ANALYTICAL METHODS ADDRESSED IN TODAY’S PROPOSED RULE

Analyte EPA method Standard method 1 Other 

§ 141.23 

Fluoride .................................................................................................................. 300.1

Nitrate ..................................................................................................................... 300.1

Nitrite ...................................................................................................................... 300.1

Orthophosphate ...................................................................................................... 300.1

§ 141.24 

Dalapon .................................................................................................................. 552.3

§ 141.131—Disinfectants 

Chlorine (free, combined, total) .............................................................................. 4500–Cl D 

4500–Cl F 

4500–Cl G 

(total) 4500–Cl E 

4500–Cl I 

(free) 4500–Cl H 

Chlorine Dioxide ..................................................................................................... 327.0 4500–ClO 2 D 

4500–ClO 2 E 

§ 141.131—Disinfection Byproducts 

HAA5 ...................................................................................................................... 552.1 2

552.3 

6251 B2

Bromate .................................................................................................................. 300.1 3

317.0 Revision 2 

321,8 4

326.0

ASTM D 6581–00 

Chlorite (monthly or daily) ...................................................................................... 300.1 3

317.0 Revision 2 

326.0

ASTM D 6581–00 

(daily) ...................................................................................................................... 327.0 4500–ClO 2 E 

§ 141.131—Other parameters 

Bromide .................................................................................................................. 300.1 3

317.0 Revision 2 

326.0

ASTM D 6581–00 

TOC/DOC ............................................................................................................... 415.3 5310 B 

5310 C 

5310 D 

UV254 ...................................................................................................................... 415.3 5910 B 

SUVA ...................................................................................................................... 415.3

§ 143.4 

Chloride .................................................................................................................. 300.1

Sulfate .................................................................................................................... 300.1 

1EPA is proposing to cite both the 20th edition and the 2003 On-Line Version of Standard Methods for the Examination of Water and Waste 

Water in addition to the currently cited 19th editions for all methods listed in this column with the exception of 4500–ClO2 D for chlorine dioxide 

which is not available in the 2003 On-Line Version. 2EPA is proposing to change the sample holding time to 14 days. 

3EPA is proposing to update the citation. 

4EPA is proposing that samples be preserved with 50 mg ethylenediamine/L and analyzed within 28 days. 

2. How Was This Proposal Developed? 

EPA evaluated the performance of the 

new methods for their applicability to 

compliance monitoring. The primary 

purpose of this evaluation was to 

determine if the new methods provide 

data of comparable or better quality than 

the methods that are currently 

approved. Methods currently approved 

for DBPs were also examined to 

determine applicability to other 

regulated contaminants. 

EPA reviewed the new publications of 

methods from consensus organizations 

such as Standard Methods and 

American Society for Testing and 

Materials (ASTM). As a result, EPA 

identified one new method from ASTM

49612 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

which is suitable for compliance 

monitoring. EPA also determined that 

the newer editions of Standard Methods 

did not change the individual methods 

approved under the Stage 1 DBPR. 

3. Which New Methods Are Proposed 

for Approval? 

a. EPA Method 327.0 for chlorine 

dioxide and chlorite. EPA is proposing 

to add a new method for the 

measurement of chlorine dioxide 

residuals and daily chlorite 

concentrations. EPA Method 327.0 

(USEPA 2003q) is an enzymatic/

spectrophotometric method in which a 

total chlorine dioxide plus chlorite 

concentration is determined in an 

unsparged sample and the chlorite 

concentration is determined in a 

sparged sample. The chlorine dioxide 

concentration is then calculated by 

subtracting the chlorite concentration 

from the total. 

The pH of the samples (sparged and 

unsparged) and blank are adjusted to 6.0 

with a citric acid/glycine buffer. The 

chromophore Lissamine Green B (LGB) 

and the enzyme horseradish peroxidase 

are added. The enzyme reacts with the 

chlorite in the sample to form chlorine 

dioxide which then reacts with the 

chromophore LGB to reduce the 

absorbance at 633nm of the sample. The 

absorbance of the samples and blank are 

determined spectrophotometrically. The 

difference in absorbance between the 

samples and the blank is proportional to 

the chlorite and total chlorine dioxide/

chlorite concentrations in the samples. 

EPA Method 327.0 offers advantages 

over the currently approved methods in 

that it is not subject to positive 

interferences from other chlorine 

species and it is easier to use. 

The single laboratory detection limits 

presented in the method are 0.08–0.11 

mg/L for chlorite and 0.04–0.16 mg/L 

for chlorine dioxide. The detection 

limits are based on the analyses of sets 

of seven replicates of reagent water that 

were fortified with low concentrations 

of chlorite with and without the 

presence of chlorine dioxide and low 

concentrations of chlorine dioxide with 

and without the presence of chlorite. 

The standard deviation of the mean 

concentration for each set of samples 

was calculated and multiplied by the 

student’s t-value at 99% confidence and 

n–1 degrees of freedom (3.143 for 7 

replicates) to determine the detection 

limit. The accuracy reported in the 

method for laboratory fortified blanks at 

concentrations of 0.2–1.0 mg/L is 103–

118 % for chlorite and 102–124 % for 

chlorine dioxide with relative standard 

deviations between 2.9 and 16 %. 

Replicate analyses of drinking water 

samples from surface and ground water 

sources fortified at concentrations of 

approximately 1 and 2 mg/L chlorite 

and chlorine dioxide showed average 

recoveries of 91–110 % with relative 

standard deviations of 1–9 %. 

EPA is proposing to approve EPA 

Method 327.0 as an additional method 

for monitoring chlorine dioxide and for 

making the daily determination of 

chlorite at the entry point to the 

distribution system. It will provide 

water systems with additional flexibility 

in monitoring the application of 

chlorine dioxide. EPA believes that 

many water plant operators will prefer 

the new method over the currently 

approved methods due to its ease of use. 

b. EPA Method 552.3 for HAA5 and 

dalapon. EPA is proposing to add a new 

method (EPA Method 552.3) for HAA5 

that provides comparable sensitivity, 

accuracy, and precision to the 

previously approved methods. EPA 

Method 552.3 (USEPA 2003p) has the 

added benefit of allowing laboratories to 

more easily measure four additional 

haloacetic acids (bromochloroacetic 

acid, bromodichloroacetic acid, 

chlorodibromoacetic acid, and 

tribromoacetic acid) at the same time 

the HAA5 compounds are being 

measured, without compromising the 

quality of data for the HAA5 

compounds. Of the currently approved 

methods for HAA5, only EPA Method 

552.2 (USEPA 1995) provides method 

performance data for all of these 

additional compounds, but the reaction 

conditions must be carefully controlled. 

EPA believes that analyses for these 

additional HAAs can be accomplished 

more easily without compromising the 

quality of data for the HAA5 

compounds by using EPA Method 

552.3. 

EPA Method 552.3 for HAA5, other 

haloacetic acids, and the regulated 

contaminant dalapon allows two 

extraction options. The first option 

involves an acidic extraction with 

methyl tertiary butyl ether (MTBE) 

which is the same solvent used in the 

currently approved HAA5 methods. The 

analytes (HAA5, other HAAs, and 

dalapon) are then converted to their 

methyl esters by the addition of acidic 

methanol to the extract followed by 

heating. The amount of acidic methanol 

that is added to the extract is increased 

in the new method resulting in 

increased methylation efficiency for 

some of the analytes. The increased 

methylation efficiency is significant for 

the additional HAAs and thus provides 

greater sensitivity, precision, and 

accuracy for them when compared to 

EPA Method 552.2. The acidic extract is 

neutralized with a saturated solution of 

sodium bicarbonate and the target 

analytes are identified and measured by 

gas chromatography using electron 

capture detection (GC/ECD). 

The second option in the new EPA 

Method 552.3 involves an acidic 

extraction with tertiary amyl methyl 

ether (TAME). The HAAs are then 

converted to their methyl esters by the 

addition of acidic methanol to the 

extract followed by heating. The use of 

TAME instead of MTBE as the 

extraction solvent allows the use of a 

higher temperature during the 

methylation process. This increases the 

methylation efficiency and thus 

provides significant increases in 

sensitivity, precision, and accuracy for 

the additional HAAs. The acidic extract 

is neutralized with a saturated solution 

of sodium bicarbonate and the target 

analytes are identified and measured by 

gas chromatography using electron 

capture detection (GC/ECD). 

The performance of EPA Method 

552.3 is comparable to the currently 

approved methods for determining the 

HAA5 analytes. A comparison of the 

performance of EPA Method 552.3 to 

the currently approved HAA5 methods 

is shown in Table V–16. The data are 

taken from the individual methods, so 

the precision, accuracy, and detection 

data were not generated using the same 

samples or by the same laboratory.

TABLE V–16.—PERFORMANCE OF HALOACETIC ACID METHODS

QC Parameter MCAA DCAA TCAA MBAA DBAA 

Precision (Max %RSD in fortified drinking water samples) 1

EPA 552.1 ................................................................................................ 15 14 28 11 7 

EPA 552.2 ................................................................................................ 13 6 15 6 5 

EPA 552.3 (MTBE option) ....................................................................... 6 4 1 4 5 

EPA 552.3 (TAME option) ....................................................................... 10 4 2 4 5 

SM 6251 B ............................................................................................... 8 7 6 8 7 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49613

TABLE V–16.—PERFORMANCE OF HALOACETIC ACID METHODS—Continued

QC Parameter MCAA DCAA TCAA MBAA DBAA 

Accuracy (Range of % Recoveries in fortified drinking water samples) 2

EPA 552.1 ................................................................................................ 76–100 75–126 56–106 86–97 94–103 

EPA 552.2 ................................................................................................ 84–97 96–105 62–82 86–100 72–112 

EPA 552.3 (MTBE option) ....................................................................... 98–126 96–103 89–100 99–113 101–111 

EPA 552.3 (TAME option) ....................................................................... 97–131 97–107 89–103 99 101–105 

SM 6251 B ............................................................................................... 99–103 96–103 100–103 97–101 102 

Detection Limit (μg/L) 3

EPA 552.1 ................................................................................................ 0.21 0.45 0.07 0.24 0.09 

EPA 552.2 ................................................................................................ 0.27 0.24 0.08 0.20 0.07 

EPA 552.3 (MTBE option) ....................................................................... 0.17 0.02 0.02 0.03 0.01 

EPA 552.3 (TAME option) ....................................................................... 0.20 0.08 0.02 0.13 0.02 

SM 6251 B ............................................................................................... 0.08 0.05 0.05 0.09 0.06 

1The highest relative standard deviation (%RSD) for replicate analyses of fortified drinking water samples as shown in each method. 2The range of recoveries reported for replicate analyses of fortified drinking water samples as shown in each method. 

3The detection limit as determined by analyzing seven or more replicates of reagent water that is fortified with low concentrations of the 

haloacetic acids. The standard deviation of the mean concentration for each analyte is calculated and multiplied by the student’s t-value at 99% 

confidence and n-1 degrees of freedom (3.143 for 7 replicates). 

Two of the currently approved HAA5 

methods (EPA Methods 552.1 (USEPA 

1992) and 552.2 (USEPA 1995)) are also 

approved for analyses of water samples 

for the regulated contaminant dalapon, 

a synthetic organic chemical. The new 

HAA5 method can also be used to 

determine dalapon in drinking water. 

As shown in Table V–17, both solvent 

options in EPA Method 552.3 provide 

comparable or better method 

performance than the approved 

methods.

TABLE V–17.—PERFORMANCE OF DALAPON METHODS

Dalapon performance characteristic EPA 552.1 EPA 552.2 

EPA 552.3 

MTBE TAME 

Precision1 (% RSD) ......................................................................................................... 14 11 2 4 

Accuracy2 (% Recovery) .................................................................................................. 88–102 86–100 98–112 87–103 

Detection Limit3 (μg/L) ..................................................................................................... 0.32 0.12 0.02 0.14 

1The highest relative standard deviation (%RSD) for replicate analyses of fortified drinking water samples as shown in each method. 2The range of recoveries reported for replicate analyses of fortified drinking water samples as shown in each method. 

3The detection limit as determined by analyzing seven or more replicates of reagent water that is fortified with low concentrations of dalapon. 

The standard deviation of the mean dalapon concentration is calculated and multiplied by the student’s t-value at 99% confidence and n-1 degrees of freedom (3.143 for 7 replicates). 

EPA is proposing to approve EPA 

Method 552.3 for dalapon 

(§ 141.24(e)(1)) in addition to HAA5 

even though dalapon is not a 

contaminant that is addressed in this 

proposed rule. EPA believes that 

extending approval to all the regulated 

contaminants covered by the method 

provides more flexibility to laboratories. 

It allows the laboratories the option of 

reducing the number of methods that 

they need to keep in operation for their 

clients, because the new method can be 

used for dalapon and HAA5 compliance 

monitoring samples and for determining 

the additional HAAs for non-regulatory 

purposes. EPA recognizes that 

laboratories will probably not be 

determining dalapon concentrations for 

compliance purposes in the same 

samples as used for HAA5 compliance 

monitoring. However, EPA believes 

allowing the same method to be used 

even if the samples are not the same is 

more cost effective for laboratories, 

because switching between methods 

results in increased analyst and 

instrument time. EPA is not proposing 

to withdraw the other dalapon methods, 

because that would reduce flexibility for 

the laboratories and place an 

unnecessary burden on laboratories that 

do not need to use EPA Method 552.3. 

c. ASTM D 6581–00 for bromate, 

chlorite, and bromide. ASTM Method D 

6581–00 (ASTM 2002) for the 

determination of bromate, chlorite, and 

bromide was adopted by ASTM in 2000. 

This method uses the same procedures 

as EPA Method 300.1 (USEPA 2000l) 

(the method promulgated in the Stage 1 

DBPR) and thus is considered 

equivalent to the approved method 

(Hautman et al. 2001). The ASTM 

method includes interlaboratory study 

data that were not available when EPA 

Method 300.1 was published. The study 

data demonstrate good precision and 

low bias for all analytes. 

Under section 12(d) of the National 

Technology Transfer and Advancement 

Act, the Agency is directed to consider 

whether to use voluntary consensus 

standards in its regulatory activities. 

ASTM Method D 6581–00 is an 

acceptable consensus standard and it is 

published in the 2001, 2002, and 2003 

editions of The ASTM Annual Book of 

Standards. EPA is proposing to approve 

ASTM Method D 6581–00 in order to 

provide additional flexibility to 

laboratories. Any edition containing the 

cited version may be used. 

d. EPA Method 317.0 revision 2 for 

bromate, chlorite, and bromide. EPA 

Method 317.0 Revision 2 (USEPA 

2001d) is an extension of the currently 

approved EPA Method 300.1 for 

bromate, chlorite, and bromide. It uses 

the EPA Method 300.1 technology, but 

it adds a postcolumn reactor that 

provides a more sensitive and specific 

analysis for bromate than is obtained 

using EPA Method 300.1. As with EPA 

Method 300.1, the anions are separated 

by ion chromatography and detected 

using a conductivity detector. (Bromate, 

chlorite, and bromide concentrations 

determined by the conductivity detector 

are equivalent to those measured using 

EPA Method 300.1.) After the sample

49614 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

passes through the conductivity 

detector, it enters a postcolumn reactor 

chamber in which o-dianisidine 

dihydrochloride (ODA) is added to the 

sample. This compound forms a 

chromophore with the bromate that is 

present in the sample and the 

chromophore concentration is 

determined using a ultraviolet/visible 

(UV/Vis) absorbance detector. There are 

several advantages of this method: 

(1) Very few ions react with ODA to 

form compounds that are detected by 

the UV/Vis detector. This makes the 

method less susceptible to interferences 

for bromate. 

(2) The UV/Vis detector is very 

sensitive to the chromophore, so lower 

concentrations of bromate can be 

detected and quantitated. (Bromate 

concentrations can be reliably 

quantitated as low as 1 μg/L using this 

detector versus 5 μg/L for EPA Method 

300.1.) 

(3) Since the front part of the analysis 

is the same as EPA Method 300.1, 

bromate, chlorite, and bromide can be 

determined in the same analysis. 

The first version of this method, EPA 

Method 317.0 has been evaluated in a 

multiple laboratory study (Wagner et al.

2001; Hautman et al. 2001). The results 

from the study indicate high precision 

and very low bias in data generated 

using this method. The interlaboratory 

precision for bromate, chlorite, and 

bromide using the conductivity detector 

and bromate using the UV/Vis detector 

are 12%, 4.2%, 6.9%, and 9.6% relative 

standard deviation (RSD), respectively. 

The interlaboratory bias for bromate, 

chlorite, and bromide using the 

conductivity detector and bromate using 

the UV/Vis detector are 0.35%, 

¥0.98%, ¥0.87%, and 4.8%, 

respectively. The average detection 

levels for bromate, chlorite, and 

bromide using the conductivity detector 

and bromate using the UV/Vis detector 

are 2.2, 1.6, 2.8, and 0.24 μg/L, 

respectively.

Subsequent to the interlaboratory 

study of EPA Method 317.0, a problem 

with ODA was discovered. The purity of 

the reagent can vary from lot to lot and 

this affects the performance of the 

method. EPA has evaluated the method 

performance using ODA obtained from 

several commercial sources and from 

different lots from the same supplier. 

Based on that new information, EPA 

revised Method 317.0 to document how 

to detect and correct problems that can 

result from a contaminated ODA supply. 

The revised method is designated EPA 

Method 317.0 Revision 2.0 and this is 

the version that is being proposed today. 

The performance of the revised method 

is identical to the original version. 

EPA believes EPA Method 317.0 

Revision 2.0 should be approved as an 

additional method for bromate, chlorite, 

and bromide compliance monitoring. 

EPA anticipates that water systems will 

prefer to have their bromate samples 

analyzed by this new method, because 

it provides higher quality data than the 

currently approved method when 

bromate concentrations are below the 

MCL of 0.010 mg/L (10 μg/L). Only a 

few laboratories are currently 

performing analyses using the 

postcolumn reactor technology included 

in the method, but the number is 

increasing as more laboratories become 

aware of the advantages. 

e. EPA Method 326.0 for bromate, 

chlorite, and bromide. EPA Method 

326.0 (USEPA 2002a) is based on the 

procedure reported by Salhi and von 

Gunten (1999) and uses an approach 

that is similar to EPA Method 317.0 

Revision 2.0. The method involves the 

separation of the anions (bromate, 

chlorite, and bromide) following the 

scheme outlined in EPA Methods 300.1 

and 317.0 Revision 2.0. (Bromate, 

chlorite, and bromide data from the 

conductivity detector are equivalent to 

data generated using EPA Method 

300.1.) The eluent stream exiting the 

conductivity detector is mixed with a 

postcolumn reagent consisting of an 

acidic solution of potassium iodide with 

a catalytic concentration of 

molybdenum (VI). Bromate reacts with 

the iodide to form triiodide which is 

measured by its UV absorption at 352 

nm. 

EPA Method 326.0 has similar 

accuracy, precision, and sensitivity for 

bromate compared to EPA Method 317.0 

Revision 2.0. Thirty drinking water 

samples fortified with 1–7 μg bromate/

L were analyzed using both methods. 

Accuracy, expressed as % recovery, 

ranged from 78.0 to 129% for both 

methods and precision, expressed as % 

RSD ranged from 3.7 to 13.5% (Wagner 

et al. 2002). The detection limit of EPA 

Method 326.0 is 0.17 μg/L as 

determined by analyzing seven or more 

replicates of reagent water that is 

fortified with low concentrations of 

bromate. The standard deviation of the 

mean bromate concentration is 

calculated and multiplied by the 

student’s t-value at 99% confidence and 

n-1 degrees of freedom (3.143 for 7 

replicates). 

EPA is proposing EPA Method 326.0 

as an additional method for bromate, 

chlorite, and bromide compliance 

monitoring. It provides higher quality 

bromate data than the currently 

approved EPA Method 300.1 when 

bromate concentrations are below 10 μg/

L. EPA anticipates the number of 

laboratories using this method will 

increase as utilities become aware of the 

method’s sensitivity and begin to 

request it be used for their samples. 

f. EPA Method 321.8 for bromate. EPA 

is proposing to add EPA Method 321.8 

(USEPA 2000d) specifically for bromate 

compliance monitoring. It involves an 

ion chromatograph coupled to an 

inductively coupled plasma mass 

spectrometer (IC/ICP–MS). The ion 

chromatograph separates bromate from 

other ions present in the sample and 

then bromate is detected and 

quantitated by the ICP–MS. Mass 79 is 

used for quantitation while mass 81 

provides isotope ratio information that 

can be used to screen for potential 

polyatomic interferences. The advantage 

of this method is that it is very specific 

and sensitive to bromate. The single 

laboratory detection limit presented in 

the method is 0.3 μg/L. The average 

accuracy reported in the method for 

laboratory fortified blanks is 99.8% 

recovery with a three sigma control 

limit of 10.2%. Average accuracy and 

precision in fortified drinking water 

samples are reported as 97.8% recovery 

and 2.9% relative standard deviation, 

respectively. 

During the Information Collection 

Rule, thirty-three samples were 

analyzed by this method in addition to 

the selective anion concentration (SAC) 

method used by EPA for the low-level 

bromate analyses. EPA Method 321.8 

provided comparable data to that 

generated by the SAC method (Fair 

2002). 

EPA Method 321.8 has undergone 

second laboratory validation (Day et al.

2001) and the results indicate the 

method can be successfully performed 

in non-EPA laboratories. The calculated 

detection limit determined by the 

second laboratory is 0.4 μg/L. The 

average accuracy achieved for laboratory 

fortified blanks at 5 μg/L is 93% 

recovery with a relative standard 

deviation of 8.9%. Average accuracy 

and precision in fortified drinking water 

samples are reported as 101% recovery 

and 9% relative standard deviation, 

respectively. 

The IC/ICP–MS instrumentation used 

in EPA Method 321.8 is a new 

technology in the drinking water 

laboratory community. Even though the 

technology is not yet widely used, EPA 

believes that approving this new 

method will provide laboratories with 

the flexibility to adopt the new 

technology if they have additional 

applications for it. The instrumentation 

is especially promising in the area of 

trace metal speciation. Laboratories that 

are performing that type of analysis 

would find it very useful to also be able

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49615

to perform bromate compliance 

monitoring analyses by EPA Method 

321.8. EPA believes that advances in 

analytical technology should be 

encouraged when they provide 

additional options for obtaining 

accurate and precise data for 

compliance monitoring. Approval of 

this method would not require 

laboratories to adopt the new 

technology; it strictly offers the choice 

for laboratories that would like to use 

the latest technology. 

EPA is proposing to add sample 

collection and holding time requirement 

to EPA Method 321.8. The current 

method does not address the potential 

for changes in bromate concentrations 

after the sample is collected as a result 

of reactions with hypobromous acid/

hypobromite ion. Hypobromous acid/

hypobromite ion are intermediates 

formed as byproducts of the reaction of 

either ozone or hypochlorous acid/

hypochlorite ion with bromide ion. If 

not removed from the sample matrix, 

further reactions may form bromate ion. 

The reactions can be prevented by 

adding 50 mg of ethylenediamine 

(EDA)/L of sample. This is the 

preservation technique specified in the 

other methods both approved and 

proposed for bromate compliance 

analyses. The fortified drinking water 

samples analyzed in the second 

laboratory validation study of EPA 

Method 321.8 (Day et al. 2001) and the 

Information Collection Rule samples 

that were analyzed using the SAC 

method and EPA Method 321.8 were 

preserved with EDA, thus 

demonstrating that EDA can be used in 

samples analyzed by IC/ICP–MS. EPA 

believes that adding this sample 

preservation requirement to EPA 

Method 321.8 will help ensure sample 

integrity. It will also simplify the 

sampling protocols that water systems 

must follow, because all sampling for 

bromate, regardless of the method 

employed to analyze the sample, will 

require the same sample preservation 

technique. 

EPA Method 321.8 does not include 

information concerning how long a 

sample may be stored prior to analysis. 

EPA is proposing to specify a maximum 

of 28 days for the sample holding time. 

This would make the method consistent 

with the other bromate methods 

proposed today and the method that is 

currently approved. 

g. EPA 415.3 for TOC and SUVA 

(DOC and UV254). Today’s rule proposes 

to add EPA Method 415.3 (USEPA 

2003r) as an approved method for TOC 

and SUVA. The Stage 1 DBPR included 

three Standard Methods for TOC and 

one method for UV254. Additional 

quality control (QC) requirements were 

included for these measurements, 

because the methods did not contain the 

necessary criteria. The rule included 

instructions for calculating SUVA based 

on UV254 and DOC analyses. The new 

EPA Method 415.3 includes the 

additional QC necessary to achieve 

reliable determinations for TOC, DOC, 

and UV254. It describes a procedure for 

removing inorganic carbon from the 

sample prior to the organic carbon 

analysis. The method uses the same 

technologies as already approved. The 

advantage of this new method is that it 

documents the precision and accuracy 

that can be expected when proper QC 

procedures are implemented and it 

places all the necessary information for 

SUVA in one place. 

EPA Method 415.3 provides 

sensitivity, precision and accuracy data 

for TOC and DOC measured using five 

different technologies: 

(1) Catalyzed 680°C combustion 

oxidation of organic carbon to carbon 

dioxide (CO2) followed by 

nondispersive infrared detection 

(NDIR). 

(2) High temperature (700 to 1100°C) 

combustion oxidation followed by 

NDIR. 

(3) Elevated temperature (95–100°C) 

catalyzed persulfate digestion of organic 

carbon to CO2 followed by NDIR. 

(4) UV catalyzed persulfate digestion 

followed by NDIR. 

(5) UV catalyzed persulfate digestion 

followed by membrane permeation into 

a conductivity detector.

These technologies are included in the 

currently approved Standard Methods 

5310 B and 5310 C (APHA, 1996). The 

new method indicates these 

technologies can provide detection 

limits between 0.02 mg/L and 0.12 mg/

L. Accuracy and precision data from 

analyses of fortified reagent water and 

natural waters indicate the technologies 

can produce acceptable data for 

determining compliance with the 

treatment technique for control of 

disinfection byproduct precursors 

specified in § 141.135. Seven natural 

waters were fortified with organic 

carbon from potassium hydrogen 

phthalate and analyzed by each of the 

five technologies. The average 

recoveries ranged from 97% to 103% for 

TOC and 98% to 106% for DOC. 

The method presents data from the 

analyses of seven different waters and 

demonstrates that comparable analytical 

results are obtained regardless of the 

technology used as long as all inorganic 

carbon is removed from the sample 

prior to the analysis. The samples 

ranged in concentration from 0.4 to 3.6 

mg/L and the relative standard 

deviations across the analyses ranged 

from 35% RSD (for the lowest 

concentration sample) to ≤13% RSD for 

the remainder of the samples. 

EPA Method 415.3 includes a 

procedure to ensure that inorganic 

carbon does not interfere with the 

organic carbon analyses. Since this is 

critical to obtaining accurate organic 

carbon determinations, EPA is 

proposing to add a requirement at 

§§ 141.131(d)(3) and (4)(i) to remove 

inorganic carbon prior to performing 

TOC or DOC analyses. Laboratories will 

have the option of using the procedure 

described in EPA Method 415.3 or 

verifying that the process used by their 

TOC instrument adequately removes the 

inorganic carbon prior to the organic 

carbon measurement. Determination of 

organic carbon by subtracting the 

inorganic carbon from the total carbon 

is not acceptable for compliance 

purposes, because the percentage of 

inorganic carbon is usually large in 

relation to the organic carbon of the 

sample and the subtraction process 

introduces a large potential for error.

The manufacturer of one of the 

instruments that was used during the 

development of EPA Method 415.3 

recommends that hydrochloric acid be 

used to acidify TOC and DOC samples 

prior to analysis. EPA confirmed that 

use of this acid is critical for proper 

operation of the instrument. However, 

use of hydrochloric acid is in conflict 

with the current regulation at 

§§ 141.131(d)(3) and (4)(i) which specify 

phosphoric or sulfuric acid. The type of 

acid used to preserve samples and to 

treat the samples to remove inorganic 

carbon prior to the organic carbon 

analysis should be based on the 

analytical method or the instrument 

manufacturer’s specification. Therefore, 

EPA is proposing to remove the 

specification of acid type from 

§§ 141.131(d)(3) and (4)(i). 

EPA Method 415.3 specifies that TOC 

samples be acid preserved at the time of 

collection in order to prevent microbial 

degradation of the organic carbon. This 

is consistent with the sampling 

instructions in the currently approved 

methods (Standard Methods 5310 B, 

5310 C, and 5310 D). EPA proposes to 

amend § 141.131(d)(3) by removing the 

phrase ‘‘not to exceed 24 hours’’ in the 

description of when samples must be 

preserved, so that the rule is consistent 

with the method specifications. 

Analyses for both DOC and UV254 are 

required for a SUVA determination. The 

DOC measurement is identical to the 

TOC measurement after the sample is 

filtered through a 0.45 μm pore size 

filter. The filtration step must be

49616 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

performed using a prewashed filter in 

order to eliminate positive interferences 

from material that can leach from 

improperly cleaned filters. EPA Method 

415.3 contains a description of how to 

properly rinse the filters and how to 

verify that the filter blank is acceptable. 

The method demonstrates that it is 

feasible to have a filter blank with a 

DOC concentration <0.2 mg/L. The 

method also provides performance data 

for DOC. 

The UV254 analysis that is part of the 

SUVA determination is also described 

in EPA Method 415.3. As with the DOC 

measurement, the UV254 analysis is 

performed on a sample that has been 

filtered through a prewashed 0.45 μm 

pore size filter. In addition to verifying 

that the filter blank is low enough, the 

method also includes a 

spectrophotometer check procedure to 

ensure that the spectrophotometer is 

operating properly. 

4. What Additional Regulated 

Contaminants Can Be Monitored by 

Extending Approval of EPA Method 

300.1? 

In addition to bromate, chlorite, and 

bromide, EPA Method 300.1 (USEPA 

2000l) can also be used to determine 

chloride, fluoride, nitrate, nitrite, 

orthophosphate, and sulfate in drinking 

water. A comparison of the performance 

of EPA Method 300.1 to the currently 

approved EPA Method 300.0 (USEPA 

1993) is shown in Table V–18 and 

demonstrates that EPA Method 300.1 

provides comparable or better precision, 

accuracy, and sensitivity for these 

contaminants based on the single 

laboratory data presented in each 

method.

TABLE V–18.—COMPARISON OF EPA METHODS 300.0 AND 300.1 

QC parameter Chloride Fluoride Nitrate Nitrite PhosphateP Sulfate 

Precision (Max % RSD in fortified water samples) 1

EPA 300.0 ........................................................................ 5.7 18 4.8 3.6 3.5 7.1 

EPA 300.1 ........................................................................ 0.22 0.85 0.41 0.77 4.7 0.39 

Accuracy (Range of % Recoveries in fortified water samples) 2

EPA 300.0 ........................................................................ 86–114 73–95 93–104 92–121 95–99 95–112 

EPA 300.1 ........................................................................ 93–98 80–89 88–96 72–87 61–92 89 

Detection Limit (mg/L) 3

EPA 300.0 ........................................................................ 0.02 0.01 0.002 0.004 0.003 0.02 

EPA 300.1 ........................................................................ 0.004 0.009 0.008 0.001 0.019 0.019 

1The highest relative standard deviation (%RSD) reported in the method for replicate analyses of fortified water samples in a single laboratory. 2The range of recoveries reported for replicate analyses of fortified water samples in a single laboratory as shown in the method. 3The detection limit as determined by analyzing seven or more replicates of reagent water that is fortified with low concentrations of the 

anions. The standard deviation of the mean concentration for each analyte is calculated and multiplied by the student’s t-value at 99% confidence and n-1 degrees of freedom (3.143 for 7 replicates). 

EPA is proposing to extend approval 

of EPA Method 300.1 for fluoride, 

nitrate, nitrite, and orthophosphate 

(§ 141.23(k)(1)) and for chloride and 

sulfate (§ 143.4(b)) even though these 

contaminants are not addressed in 

today’s proposed rule. As discussed 

before for dalapon, EPA believes that 

extending approval to all the regulated 

contaminants covered in a method 

provides greater flexibility to 

laboratories and allows them to reduce 

analytical costs. EPA recognizes that 

laboratories will probably not be 

determining concentrations of these 

non-DBP anions for compliance 

purposes in the same samples as used 

for chlorite or bromate compliance 

monitoring. However, EPA believes 

allowing the same method to be used 

even if the samples are not the same is 

more cost effective for laboratories. EPA 

is not proposing to withdraw any 

methods for the non-DBP anions, 

because that would place an 

unnecessary burden on laboratories that 

do not need to use EPA Method 300.1. 

5. Which Methods in the 20th Edition 

and 2003 On-Line Version of Standard 

Methods Are Proposed for Approval? 

The Stage 1 DBPR approved eight 

methods (4500–Cl D, 4500–Cl F, 4500–

Cl G, 4500–Cl E, 4500–Cl I, 4500–Cl H, 

4500–ClO2 D, and 4500–ClO2 E) for 

determining disinfection residuals from 

the 19th edition of Standard Methods 

(APHA, 1995). Standard Methods 6251 

B and 4500–CIO2 E in the 19th edition 

of Standard Methods (APHA, 1995) 

were approved for HAA5 and daily 

chlorite analyses, respectively. Three 

TOC methods (5310 B, 5310 C, and 5310 

D) from the Supplement to the 19th 

edition of Standard Methods (APHA, 

1996) and one UV254 method (5910 B) 

from the 19th edition of Standard 

Methods (APHA, 1995) were also 

approved in the Stage 1 DBPR. 

These thirteen methods are 

unchanged in the 20th edition of 

Standard Methods (APHA, 1998), so 

EPA proposes to cite the 20th edition for 

these analyses in addition to the 19th 

editions. 

The On–Line Version of Standard 

Methods is an effort to provide the 

consensus methods to the public prior 

to the release of the next full 

publication. Standard Methods is 

making sections of the next version 

available for purchase in both electronic 

or printed format. EPA has reviewed the 

applicable sections and determined that 

ten of the methods are identical to the 

currently approved versions from the 

19th editions. Section 4500–Cl contains 

the methods for determining chlorine 

residuals and it includes the 4500–Cl D, 

4500–Cl F, 4500–Cl G, 4500–Cl E, 4500–

Cl I, and 4500–Cl H. Section 4500–ClO2

contains the methods for determining 

chlorine dioxide residuals and chlorite 

and it includes method 4500–ClO2 E. 

Section 5310 contains the methods for 

determining TOC and it includes 

methods 5310 B, 5310 C, and 5310 D. 

Because the ten listed methods in these 

sections are unchanged from the 

versions that were published in the 19th 

editions, EPA is proposing to cite the 

On–Line Version for these analyses in

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49617

addition to the currently approved 19th 

editions and the proposed 20th edition. 

Section 6251 includes method 6251 B 

for HAA5. The method has been 

updated for the On–Line Version to 

include precision and accuracy data 

from the Information Collection Rule 

and the sample holding time has been 

extended from 9 days to 14 days. The 

additional quality control data does not 

technically change the method from the 

previously approved version in the 19th 

edition; it simply demonstrates the 

performance that can be expected when 

the method is used. The change in 

sample holding time is consistent with 

EPA’s proposal to standardize the HAA5 

sample holding time at 14 days (See

discussion in section V.O.7). Thus EPA 

is proposing to cite the On–Line Version 

for this analysis in addition to the 

currently approved 19th edition and the 

proposed 20th edition. 

Section 5910 includes method 5910 B 

for determining UV254. The method has 

been updated for the On–Line Version 

to include precision data from the 

Information Collection Rule. Because 

the additional quality control data does 

not technically change the method from 

the previously approved version in the 

19th edition, EPA is proposing to cite 

the On–Line Version for this analysis in 

addition to the currently approved 19th 

edition and the proposed 20th edition. 

The On–Line Version of Standard 

Methods will not include method 4500–

ClO2 D, so it is not being proposed with 

the other twelve methods cited in the 

On–Line Version. 

EPA is proposing to add a citation to 

the 20th edition and the On–Line 

Version of Standard Methods for 

thirteen and twelve methods, 

respectively. EPA believes these should 

be cited in addition to the 19th editions 

in order to allow flexibility for the water 

systems performing the analyses. 

Withdrawal of the older editions would 

require all systems to purchase one of 

the newer editions, which could impose 

an unnecessary burden on systems that 

use the reference for only a few 

methods. 

6. What Is the Updated Citation for EPA 

Method 300.1? 

EPA Method 300.1 (USEPA 2000l) for 

bromate, chlorite and bromide is now 

included in an EPA methods manual 

that was published August 2000. The 

manual titled ‘‘Methods for the 

Determination of Organic and Inorganic 

Compounds in Drinking Water’’ is a 

compilation of methods developed by 

EPA for drinking water analyses. EPA 

Method 300.1 was previously only 

available as an individual method. EPA 

proposes to update the bromate, 

chlorite, and bromide citation for this 

method to the August 2000 methods 

manual in today’s rule so that the users 

are directed to the correct source of the 

method. 

7. How Is the HAA5 Sample Holding 

Time Being Standardized? 

The analytical methods approved for 

HAA5 compliance monitoring (EPA 

552.1, EPA 552.2, and Standard Method 

6251 B) all specify the use of 

ammonium chloride to eliminate the 

free chlorine residual in samples and 

they require samples be iced/

refrigerated after collection. Even 

though the sampling parameters agree in 

the three methods, the methods specify 

different sample holding times (time 

between sample collection and 

extraction). EPA Methods 552.1 (USEPA 

1992) and 552.2 (USEPA 1995) allow at 

least 14 days while Standard Method 

6251 B (APHA 1995 and 1998) specifies 

that samples must be extracted within 

nine days of sample collection. The 

holding time for the Standard Method is 

based on data which indicated an 

increase in DCAA concentration to 

slightly greater than 120% of the initial 

concentration after the sample was 

stored for 14 days (Krasner et al. 1989). 

All other HAA5 compounds were well 

within the 80–120% criteria set by the 

researchers. The decision was made to 

use a conservative approach to be sure 

that the concentrations of all HAAs 

were stable, and nine days was the 

closest data point to the 14 day–data 

point in question. Subsequent to 

Krasner’s study, EPA conducted 

additional sample holding time studies 

as part of the EPA methods 

development process. EPA has 

published data to support the 14–day 

sample holding time for the HAA5 

compounds (Pawlecki–Vonderheide et 

al. 1997; USEPA 2003p). Since there is 

no technical reason for the holding 

times to be different between the HAA5 

methods addressed in this rule, EPA 

proposes to allow a 14–day sample 

holding time for samples being analyzed 

by Standard Method 6251 B. This would 

provide consistency across methods and 

it would simplify sampling 

considerations for water systems. EPA is 

only proposing to standardize the 

holding time allowed for the samples. 

Due to differences in the sample 

preparation (i.e., extraction) procedures 

in the various methods, the extract 

holding times cannot be standardized. 

Laboratories must follow the individual 

method requirements when determining 

storage conditions and holding times for 

the extracts. 

EPA Method 552.1 specifies a 28–day 

holding time for HAA samples. This 

was based on studies conducted on 

fortified reagent water samples rather 

than drinking water samples. Because 

HAAs have been shown to biodegrade 

in some distribution systems (Williams 

et al. 1995), EPA believes that some 

samples may not be stable for 28 days. 

Today’s rule proposes reducing the 

holding time to 14 days when EPA 

Method 552.1 is used in order to better 

ensure sample stability. During the 

Information Collection Rule, EPA only 

allowed the 14–day sample holding 

time for all HAA samples (regardless of 

the method used to analyze the 

samples), so laboratories and water 

systems have demonstrated their 

capability to implement this method 

change.

EPA believes that by standardizing 

the sample holding times allowed in the 

various HAA5 methods, the burden for 

laboratories and water systems will be 

reduced. Sampling considerations will 

be simplified, because all HAA5 

samples will be collected and stored the 

same way. 

8. How Is EPA Clarifying Which 

Methods Are Approved for Magnesium 

Determinations? 

The Stage 1 DBPR allows systems 

practicing enhanced softening that 

cannot achieve the specified level of 

TOC removal, to meet instead one of 

several alternative performance criteria, 

including the removal of 10 mg/L 

magnesium hardness (as CaCO3) from 

the source water. Analytical methods for 

measuring magnesium hardness were 

not included in the rule, but they were 

later promulgated in a Methods Update 

Rule (USEPA 1999b). The December 

1999 Methods Rule cited the 

magnesium methods at § 141.23(k)(1), 

but it did not identify that these 

methods were to be used to demonstrate 

compliance with the alternative 

performance criteria specified in 

§ 141.135(a)(3)(ii). EPA is proposing to 

clarify this today by referencing the 

approved magnesium methods at 

§ 141.131(d)(6) and § 141.135(a)(3)(ii). 

9. Which Methods Can Be Used To 

Demonstrate Eligibility for Reduced 

Bromate Monitoring? 

Today’s rule proposes to change the 

monitoring requirements for 

demonstrating eligibility to reduce 

bromate monitoring from monthly to 

quarterly. The Stage 1 DBPR allows the 

monitoring to be reduced if the system 

demonstrates that the average source 

water bromide concentration is less than 

0.05 mg/L based upon monthly bromide 

measurements for one year. Today’s rule 

proposes to change that requirement to 

a demonstration that the finished water

49618 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

bromate concentration is <0.0025 mg/L 

as a running annual average. If this 

change is implemented, there will no 

longer be a need for bromide 

compliance monitoring methods. EPA is 

proposing additional bromide methods 

today in order to provide flexibility to 

the laboratories and water systems in 

the interim period before the Stage 2 

DBPR compliance monitoring 

requirements becomes effective. 

In order to qualify for reduced 

bromate monitoring, EPA is proposing 

that the samples must be analyzed for 

bromate using either EPA Method 317.0 

Revision 2.0 (UV/Vis detector), EPA 

Method 326.0 (UV/Vis detector), or EPA 

Method 321.8. These three methods can 

provide quantitative data for bromate 

concentrations as low as 0.001 mg/L, 

thus ensuring that a bromate running 

annual average of <0.0025 mg/L can be 

reliably demonstrated. Laboratories that 

analyze samples by these three methods 

must report quantitative data for 

bromate concentrations as low as 0.001 

mg/L. 

Since EPA Methods 317.0 Revision 

2.0, 326.0, and 321.8 offer significantly 

greater sensitivity for bromate analyses, 

EPA considered whether these should 

be the only methods approved for 

bromate compliance monitoring. 

However, the new methods using 

postcolumn reactions with UV/Vis 

detection (EPA Methods 317.0 Revision 

2.0 and 326.0) or IC/ICP–MS (EPA 

Method 321.8) require greater analyst 

skill than is necessary for the standard 

ion chromatographic (IC) methodology 

(EPA Method 300.1 and ASTM Method 

D 6581–00). They also require 

instrumentation that may not be 

currently owned by many laboratories 

that perform bromate analyses. As a 

result of these factors and because the 

standard IC methods are adequate for 

determining compliance with the 

bromate MCL that was promulgated as 

part of the Stage 1 DBPR, EPA decided 

not to propose withdrawal of the 

currently approved method (EPA 

Method 300.1). In addition, EPA 

decided to propose ASTM Method D 

6581–00, because it is equivalent to EPA 

Method 300.1. EPA strongly encourages 

laboratories to expand their services by 

adding the capability to perform 

analyses using one of the more sensitive 

methods for bromate. EPA believes that 

there will be a shift to the more 

sensitive methods as water systems 

realize that the analytical capabilities 

are available for a slightly increased 

analytical cost. (The ability to determine 

bromate concentrations as low as 1 μg/

L will provide water systems more 

information concerning the 

optimization of ozone application to 

control for bromate formation.) 

10. Request for Comments 

EPA requests comments on whether 

the methods proposed today should be 

approved for compliance monitoring. 

EPA solicits comments as to whether 

standardizing the sample holding times 

for the HAA5 methods is appropriate. 

Specifically, should the sample holding 

time for Standard Method 6251 B be 

extended from 9 days to 14 days and 

should the sample holding time for EPA 

Method 552.1 be shortened from 28 

days to 14 days? 

EPA requests comments as to whether 

laboratories should be required to 

switch to one of the more sensitive 

bromate methods for compliance 

monitoring sample analyses. Should 

EPA Method 300.1 be withdrawn as a 

compliance monitoring method for 

bromate and be replaced by EPA 

Methods 317.0 Revision 2.0, 326.0, and 

321.8 which provide reliable data for 

bromate concentrations as low as 1μg/L? 

P. Laboratory Certification and 

Approval 

1. What Is EPA Proposing Today? 

EPA recognizes that the effectiveness 

of today’s proposed regulation depends 

on the ability of laboratories to reliably 

analyze the regulated disinfection 

byproducts at the proposed MCLs. EPA 

has established a drinking water 

laboratory certification program that 

States must adopt as part of primacy. 

Laboratories must be certified in order 

to analyze samples for compliance with 

the MCLs. EPA has also specified 

laboratory requirements for analyses, 

such as alkalinity, bromide, disinfectant 

residuals, magnesium, TOC, and SUVA, 

that must be conducted by parties 

approved by EPA or the State. EPA’s 

‘‘Manual for the Certification of 

Laboratories Analyzing Drinking Water’’

(USEPA 1997b) specifies the criteria 

that EPA uses to implement the 

drinking water laboratory certification 

program. Today’s proposed rule 

maintains the requirements of 

laboratory certification for laboratories 

performing analyses to demonstrate 

compliance with MCLs and all other 

analyses to be conducted by approved 

parties. It revises the acceptance criteria 

for performance evaluation (PE) studies 

and proposes reporting limits for the 

DBPs as part of the certification 

program. Today’s rule also proposes that 

TTHM and HAA5 analyses that are 

performed for the IDSE or systemspecific study be conducted by 

laboratories certified for those analyses. 

2. What Changes Are Proposed for the 

PE Acceptance Criteria? 

The Stage 1 DBPR specified that in 

order to be certified the laboratory must 

pass an annual performance evaluation 

(PE) sample approved by EPA or the 

State using each method for which the 

laboratory wishes to maintain 

certification. The acceptance criteria for 

the DBP PE samples were set as 

statistical limits based on the 

performance of the laboratories in each 

study. This was done because EPA did 

not have enough data to specify fixed 

acceptance limits. 

Subsequent to the 1998 promulgation, 

EPA evaluated the results for the EPA 

Water Supply (WS) PE studies and the 

Information Collection Rule PE studies 

to determine if fixed acceptance limits 

could now be applied. (Fixed limits 

were used during the Information 

Collection Rule). 

Four different fixed limits (±20%, 

±30%, ±40%, and ±50% of the true 

value) were applied to each analyte in 

the WS PE study TTHM, HAA5, 

bromate, and chlorite samples. 

Successful analysis of the sample was 

defined as passing all four THMs 

individually in the TTHM PE sample; 

passing four of the five HAAs in the 

HAA5 PE sample; and passing bromate 

and chlorite individually. The number 

and percentage of laboratories that 

successfully passed each study sample 

were determined for the four fixed 

limits. These results were then 

evaluated to determine how narrow the 

criteria could be set in order to achieve 

accurate data and also provide enough 

certified laboratories to meet the 

capacity needs. Only the last six WS PE 

Studies administered by EPA (WS36–

WS41 conducted between 1996–1998) 

were used in the final recommendation, 

because they provided a better estimate 

of current laboratory capabilities. Table 

V–19 summarizes the results of this WS 

PE Study evaluation. 

The number of laboratories that 

analyzed WS TTHM PE samples was 

significantly larger than for the other 

DBPs, because a laboratory certification 

program for TTHM has been in effect 

since the promulgation of the THM rule 

in 1979 (USEPA 1979). Most of the 

analytical methods for TTHM have been 

in use for many years, and the 

laboratories are experienced in their 

use. The Stage 1 DBPR established the 

first requirements to monitor for the 

other DBPs and certification was not 

required until December 2001. 

Therefore, the WS PE results for HAA5, 

chlorite, and bromate were from 

laboratories that were not part of a 

certification process and the laboratories

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49619

were using methods that were relatively 

new. In addition, the method used for 

bromate during the WS studies was EPA 

Method 300.0 which was replaced by 

EPA Method 300.1 in the Stage 1 DBPR, 

because Method 300.1 is more sensitive. 

Laboratories would be expected to have 

greater success in passing the bromate 

PE samples using Method 300.1 and the 

bromate methods that are being 

proposed in today’s rule.

TABLE V–19.—FIXED LIMIT EVALUATION OF WS PE STUDIES 36—41 

[Average # and % of labs successfully completing studies] 

DBP Sample 

±20% of TV ±30% of TV ±40% of TV ±50% of TV 

#Labs %Labs #Labs %Labs #Labs %Labs #Labs %Labs 

TTHM ............................................................... 609 73 731 88 773 93 788 94 

HAA5 1 .............................................................. 50 37 83 61 103 75 115 84 

chlorite .............................................................. 55 63 68 78 72 82 74 85 

bromate ............................................................ 45 50 52 57 57 64 60 68 

1Study 38 was excluded from this analysis, because a valid DCAA true value was not available for the HAA sample. 

Based on the results from the analyses 

described previously, EPA believes it is 

reasonable to set the TTHM acceptance 

criteria at ±20% around the study true 

values. The number of laboratories 

capable of performing TTHM analyses is 

large and the results described 

previously show that in the time frame 

of 1996–1998, over 70% of the 

laboratories could successfully meet the 

±20% criteria. The PE studies 

conducted during the Information 

Collection Rule used the same 

acceptance criteria (USEPA 1996b). 

The data indicate that ±40% are 

probably the tightest criteria that could 

be used to evaluate HAA5 PE samples. 

Setting this criteria balances the need 

for approval of enough labs to meet 

monitoring capacity and the need to 

provide data of acceptable accuracy. 

The ±40% criteria is consistent with the 

Information Collection Rule PE study 

acceptance criteria and it is tighter than 

the criteria established in the Stage 1 

DBPR. During the Information 

Collection Rule, laboratories that were 

approved using the ±40% criteria were 

able to provide accurate and precise 

data as evidenced by the quality control 

data collected when the Information 

Collection Rule samples were analyzed 

(Fair et al. 2002). Of the 1,250 

Information Collection Rule samples 

that were fortified with known amounts 

of HAAs, the median recovery was 

103% and the recoveries ranged 

between 89% and 120% in 80% of the 

fortified samples. There were 1,211 

Information Collection Rule samples 

that were analyzed in duplicate and the 

median relative percent difference for 

those HAA5 analyses was 4%. Ninety 

percent of the analyses had RPDs less 

than 21%. EPA believes laboratories 

that are certified using the ±40% criteria 

in PE studies should be capable of 

performing at a level comparable to the 

Information Collection Rule 

laboratories. 

EPA believes chlorite PE samples 

should be evaluated using a ±30% 

criteria. Over 70% of the laboratories 

could meet this requirement for chlorite 

in the WS studies. 

The percentage of passing labs for 

bromate is almost 60% when a ±30% 

criteria is applied to the WS study data. 

Since the data do not accurately reflect 

the bromate methods that are now being 

used by laboratories, EPA believes a 

greater percentage of laboratories would 

pass the bromate PE study using today’s 

technology. Unfortunately, EPA does 

not have the data to verify this 

assumption, because EPA no longer 

conducts PE studies. Even if the 

assumption is flawed, a 57% acceptance 

rate would still provide enough certified 

laboratories to handle the number of 

bromate samples required for 

compliance monitoring under the Stage 

1 DBPR. 

The proposed acceptance criteria are 

listed in Table V–20.

TABLE V–20.—PROPOSED PERFORMANCE EVALUATION (PE) ACCEPTANCE CRITERIA

DBP 

Acceptance

limits

(percent) 

Comments 

TTHM 

Chloroform 

Bromodichloromethane 

Dibromochloromethane 

Bromoform 

±20 

±20 

±20 

±20 

Laboratory must meet all 4 individual THM acceptance limits in 

order to successfully pass a PE sample for THMs. 

HAA5 

Monochloroacetic Acid 

Dichloroacetic Acid 

Trichloroacetic Acid 

Monobromoacetic Acid 

Dibromoacetic Acid 

±40 

±40 

±40 

±40 

±40 

Laboratory must meet the acceptance limits for 4 out of 5 of 

the HAA5 compounds in order to successfully pass a PE 

sample for HAA5. 

Chlorite ±30 

Bromate ±30 

EPA is also proposing that the PE 

acceptance limits described previously 

become effective within 60 days of 

promulgation of the final rule. This will 

allow the laboratory certification 

program to implement the fixed limits 

as soon as possible. Laboratories that 

were certified under the Stage 1 PE 

acceptance criteria would be subject to 

the new criteria when it is time for them 

to analyze their annual DBP PE 

samples(s).

49620 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

3. What minimum reporting limits are 

being proposed? 

The Consumer Confidence Reports 

Rule (USEPA 1998i) requires that all 

detected regulated contaminants be 

reported in the annual reports, but 

detection is not defined for the DBP 

contaminants. This rule addresses the 

deficiency by proposing reporting limits 

for the regulated DBPs.

Laboratories that analyze compliance 

samples must be able to reliably 

measure the DBPs at concentrations 

below the MCL. Laboratories must also 

be able to measure the individual TTHM 

and HAA5 compounds at levels that are 

much lower than the MCLs for these 

compound classes, because the MCLs 

are based on the sum of the individual 

compound concentrations. 

Historically, EPA has used practical 

quantitation levels to estimate the 

lowest concentration at which 

laboratories can be expected to provide 

data within specified limits of precision 

and accuracy during routine operating 

conditions (USEPA 1985). The estimates 

are based on PE data, if available, or are 

set at five or ten times the method 

detection level. 

In today’s rule, EPA is proposing an 

alternate approach for establishing the 

lowest concentration for which 

laboratories are expected to report 

quantitative data for DBPs. The 

approach is based on a unique data set 

from the Information Collection Rule. 

Laboratories were required to meet 

specific quality control criteria when 

they analyzed samples for the 

Information Collection Rule. The rule 

established a regulatory minimum 

reporting level (MRL) for each analyte 

and laboratories were required to 

demonstrate they could accurately 

measure at these concentrations each 

time a set of samples was analyzed. The 

regulatory MRLs were based on 

recommendations from experts who 

were experienced in DBP analyses and 

were set at concentrations for which 

most laboratories were expected to be 

able to meet the precision and accuracy 

criteria under normal operating 

conditions. Most samples were also 

expected to contain concentrations 

greater than the specified MRLs. 

EPA evaluated the data from the 

Information Collection Rule to 

determine if the laboratories were able 

to reliably measure down to the 

required MRL concentrations. Precision 

and accuracy data from the calibration 

check standards prepared at the MRL 

concentrations (listed in Table V–21) 

were examined. The data indicated most 

laboratories were able to provide 

quantitative data for samples with these 

concentrations. 

Because laboratories demonstrated the 

capability to meet the Information 

Collection Rule MRLs, EPA believes it is 

reasonable to expect similar 

performance during the analyses of DBP 

compliance monitoring samples. In 

today’s rule, EPA is proposing to 

incorporate MRL requirements into the 

laboratory certification program for 

DBPs and to use regulatory MRLs as the 

minimum concentrations that must be 

reported as part of the Consumer 

Confidence Reports (§ 141.151(d)).

TABLE V–21.—PROPOSED MINIMUM REPORTING LEVEL (MRL) REQUIREMENTS

DBP 

MRL (μg/L) 

Information Comments 

collection

rule 

Proposed stage 

2 DBPR 

TTHM 

Chloroform ........................................................... 1.0 1.0 

Bromodichloromethane ........................................ 1.0 1.0 

Dibromochloromethane ........................................ 1.0 1.0 

Bromoform ........................................................... 1.0 1.0 

HAA5 

Monochloroacetic Acid ......................................... 2.0 2.0 

Dichloroacetic Acid .............................................. 1.0 1.0 

Trichloroacetic Acid .............................................. 1.0 1.0 

Monobromoacetic Acid ........................................ 1.0 1.0 

Dibromoacetic Acid .............................................. 1.0 1.0 

Chlorite ........................................................................ 20.0 200.0 

Bromate ....................................................................... 5.0 5.0 or 1.0 Laboratories that use EPA Methods 317.0 Revision 

2.0, 326.0, or 321.8 must meet a 1.0 μg/L MRL 

for bromate. 

As part of the request for certification, 

EPA is proposing to require laboratories 

to demonstrate they can reliably 

measure concentrations at least as low 

as the ones listed in Table V–21 in order 

to be certified for those parameters. This 

would mean that the calibration curve 

must encompass the proposed 

regulatory MRL concentration and that 

the laboratory must verify the accuracy 

of the calibration curve at the lowest 

concentration for which quantitative 

data are reported by analyzing a 

calibration check standard at that 

concentration prior to analyzing each 

batch of samples. (Laboratories would 

analyze a check standard at the 

specified MRL concentration daily or 

each time samples are analyzed.) The 

measured concentration for this check 

standard must be within ±50% of the 

expected value. Laboratories may 

choose to report quantitative data at 

concentrations lower than the proposed 

regulatory MRLs as long as the required 

accuracy criteria (±50% of the expected 

value) is met by daily analyzing 

standards at the lowest reporting limit 

chosen by the laboratory. 

Laboratories were not given the 

opportunity to report concentrations 

lower than the specified MRLs during 

the Information Collection Rule. Some 

laboratories indicated they have met the 

precision and accuracy criteria at lower 

concentrations, so EPA believes that 

each laboratory should have the 

flexibility to continue using its own 

reporting limits as long as the laboratory 

MRLs are not higher than the regulatory 

ones proposed in this rule. This 

flexibility would minimize the cost of 

implementing the regulatory MRL 

requirements, because the laboratory 

would not have to make changes in its 

established quality control procedures 

unless its procedures are less stringent 

than those being proposed today. 

Requiring a laboratory to adopt 

regulatory MRLs that are higher than the 

laboratory reporting limits currently in

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49621

use offers no advantage and could 

increase analytical costs. The capability 

to provide quantitative data at the 

laboratory’s MRL or the regulatory MRL 

would need to be demonstrated on a 

daily basis by analyzing a check 

standard at that concentration and by 

achieving a recovery in the range of 50 

to 150%. 

The proposed regulatory MRL for 

MCAA is 2.0 μg/L based on the 

Information Collection Rule 

performance data. However, MCAA was 

not present at concentrations higher 

than this in more than half of the 

samples analyzed for HAAs during the 

Information Collection Rule (USEPA 

2003o). Some laboratories reported that 

they could have provided quantitative 

data for MCAA down to concentrations 

as low as 1.0 μg/L. 

EPA is proposing a regulatory MRL 

for chlorite that is much higher than can 

easily be achieved using the approved 

or proposed methods. The MRL 

specified during the Information 

Collection Rule was 20. μg/L and 

laboratories were able to successfully 

obtain quantitative data at that level. 

However, in the context of this rule, 

EPA believes that requiring laboratories 

to verify their calibration curves down 

to 20. μg/L each time samples are 

analyzed is unnecessary. This is because 

chlorite analyses are only performed on 

samples from water plants that use 

chlorine dioxide and most of the 

applied chlorine dioxide is converted to 

chlorite, so the concentrations that are 

expected in most compliance 

monitoring samples will be much higher 

than 20. μg/L. (The Information 

Collection Rule data showed a median 

chlorite concentration of 380 μg/L in the 

finished water and 333 μg/L as the 

distribution system average in systems 

using chlorine dioxide (USEPA 2003o).) 

EPA is proposing a regulatory MRL of 

200. μg/L for chlorite, because most of 

the samples are expected to contain 

concentrations higher than 200. μg/L. 

The MCL for chlorite is 1.0 mg/L (1,000 

μg/L). EPA recognizes that setting the 

regulatory MRL for chlorite based on the 

concentrations expected to be found in 

the samples rather than the sensitivity 

of the analytical method is inconsistent 

with the approach taken for other 

compounds in this rule. Nevertheless, 

EPA believes setting the MRL based on 

occurrence information is appropriate 

because it will not compromise the 

compliance data. Water systems would 

have the option of requiring that 

laboratories establish a lower reporting 

limit when their samples are analyzed 

and EPA would encourage this in cases 

in which the samples consistently 

contain chlorite concentrations that are 

<200. μg/L. If a lower reporting limit is 

used, then the laboratory will be 

required to meet the precision and 

accuracy requirements at that lower 

concentration by daily successfully 

analyzing a check standard at the 

laboratory reporting limit concentration 

prior to analyzing compliance samples. 

EPA believes very few water systems 

will request more sensitive chlorite 

analyses, because their samples won’t 

have low enough concentrations to 

require it. 

EPA is proposing two regulatory 

MRLs for bromate analyses in today’s 

rule. This is because the traditional ion 

chromatographic (IC) methods using 

conductivity detection (EPA Method 

300.1 and ASTM Method 6581–00) are 

only capable of quantitating down to 5.0 

μg/L while the new IC methods using 

either post column reactions with UV/

Vis detection (EPA Methods 317.0 

Revision 2.0 and 326.0) or IC followed 

by ICP–MS detection (EPA Method 

321.8) can reliably quantitate bromate 

concentrations as low as 1.0 μg/L. EPA 

believes it is appropriate to set the 

regulatory MRL based on the capability 

of the method. (EPA has published 

detection limits for inorganic 

contaminants based on method 

capability (§ 141.23(a)(4)(i)), so the 

approach proposed today is consistent 

with previous regulations.) If the 

regulatory MRL is based on the most 

sensitive method, then the routine IC 

methods could no longer be used even 

though they are adequate for 

demonstrating compliance with the 

bromate MCL. If the regulatory MRL is 

set using the least sensitive method, 

then the feasibility for reduced bromate 

monitoring based on a running annual 

average of <0.0025 μg/L (<2.5 μg/L) 

would not be adequately demonstrated 

based on data reported with a reporting 

limit of 5.0 μg/L.

EPA is proposing MRLs as part of the 

certification process. Laboratories 

would be required to demonstrate they 

can reliably quantitate at the specified 

MRL concentration when their current 

DBP certification is subject to renewal 

or if they are applying for certification 

for DBP methods for the first time. 

(Demonstration would be accomplished 

by providing precision and accuracy 

data from the analyses of check 

standards at or below the regulatory 

MRL concentration over a several day 

period. The laboratory’s standard 

operating procedure for HAA5 analyses 

would include a requirement to daily 

meet the MRL accuracy criteria for a 

check standard at or below the 

regulatory MRL concentration.) 

Although ensuring laboratories can meet 

the regulatory MRLs is a new 

certification requirement, EPA does not 

believe this significantly increases the 

time required to review a laboratory 

prior to certification. Each DBP method 

requires the laboratory to generate a 

similar set of data at a higher 

concentration and to meet specific 

accuracy and precision criteria as part of 

the initial demonstration of laboratory 

capability to perform the method; 

review of the MRL data set will be 

comparable to what is already being 

done. This new requirement will ensure 

that laboratories can reliably analyze 

samples that contain low concentrations 

of DBPs on an on-going basis. 

EPA is also proposing to require the 

regulatory MRLs be used for compliance 

reporting by the Public Water Systems. 

Finally, the regulatory MRLs would be 

used when Public Water Systems inform 

customers of their water quality relative 

to DBP concentrations in the annual 

Consumer Confidence Reports. 

4. What Are the Requirements for 

Analyzing IDSE Samples? 

EPA is proposing that the TTHM and 

HAA5 samples collected for the Initial 

Distribution System Evaluations (IDSE) 

and the system specific studies 

conducted in lieu of IDSEs be analyzed 

by certified laboratories. EPA recognizes 

that this will require additional 

laboratory capacity during the time 

period in which these studies are 

conducted. The largest challenge will be 

in developing the capacity to analyze 

the samples for the water systems that 

must complete the studies, analyze the 

data, and recommend Stage 2 DBP 

sampling sites within two years of the 

promulgation date of the rule. However, 

EPA believes commercial laboratories, 

in particular, will be able to expand 

their capacity to meet the demand based 

in the information presented below. 

Assuming no waivers or systemspecific studies, the number of IDSE 

samples is estimated to be between 

14,000 and 21,000 per month in the first 

round of IDSE monitoring, depending 

on whether the monitoring requirements 

are based on population or number of 

treatment plants, respectively. 

Laboratories should easily be able to 

accommodate this increase in TTHM 

samples, because experience performing 

TTHM analyses is spread across a large 

number of laboratories. Hundreds of 

laboratories have been certified for 

TTHM analyses, since certification was 

first required in 1979. There were close 

to 600 laboratories certified to perform 

TTHM analyses in 1991. In the 1996–

1998 period, there were over 800 

laboratories participating in the PE 

studies for TTHMs and 600 of those 

laboratories were capable of meeting the

49622 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

TTHM PE acceptance criteria proposed 

in today’s rule. Many water system 

laboratories are certified to perform 

TTHM analyses and will be able to 

incorporate the IDSE TTHM samples 

from their systems into the laboratory 

schedule. It is reasonable to expect that 

commercial laboratories will be able to 

handle the remainder of the TTHM 

samples. (EPA does not have a current 

estimate of the number of laboratories 

certified to perform TTHM analyses. 

However, if the number of IDSE samples 

from large systems was evenly spread 

over the 600 laboratories that were 

certified in 1991, this would be less 

than 40 additional samples per month 

for each laboratory. Analysis of 40 

TTHM samples would involve less than 

two days of analyst and instrument time 

which does not seem unreasonable for 

commercial laboratories to 

accommodate.) 

Analyses of the HAA5 samples will 

present a greater challenge, because 

certification is relatively new for this 

measurement. EPA anticipates that most 

of the HAA5 samples will be analyzed 

by commercial and State laboratories, 

because the methods are more complex 

than the TTHM analyses and monitoring 

was not widely required until January 

2002. Laboratories were not required to 

be certified to perform HAA5 analyses 

until January 2002. However, the PE 

Study results from 1996–1998 indicate 

that over 130 laboratories were 

performing HAA5 analyses during that 

time frame and approximately 100 of 

those laboratories were capable of 

meeting the HAA5 PE acceptance 

criteria proposed in today’s rule. 

Ninety-four laboratories were approved 

to perform HAA analyses during the 

Information Collection Rule; twentyseven of them were commercial 

laboratories and nine were State 

laboratories. EPA anticipates that large 

commercial laboratories already 

certified to perform HAA5 analyses will 

recognize this market potential and add 

staff and instrumentation to 

accommodate the increased demand. 

Most systems serving <10,000 people 

will not begin their IDSE studies until 

after the large systems have completed 

their studies. Even though the potential 

number of samples is greater, the small 

systems have two additional years in 

which to complete their studies, so 

there is more opportunity to schedule 

the sampling in such a manner that 

laboratory capacity is maintained. The 

laboratory capacity should be readily 

available by the time analyses of these 

samples are required. 

5. Request for Comments 

EPA requests comments concerning 

the appropriateness of the proposed PE 

acceptance criteria. 

EPA solicits comments as to whether 

an MRL lower than 2 μg/L is feasible for 

MCAA and if so, what should that MRL 

concentration be? 

EPA requests comments concerning 

whether the MRL for chlorite should be 

based on the sensitivity of the method 

(i.e., 20. μg/L) or on the expected 

concentration range of the samples (i.e., 

200. μg/L).

EPA solicits comments concerning 

which MRL approach should be 

considered for bromate. Specifically, 

should EPA set the MRL based on the 

capability of the method which would 

mean that two different MRLs are 

defined or should one MRL be 

established based on either the least or 

most sensitive method? 

EPA requests comments concerning 

the appropriateness of the MRL 

certification requirements and whether 

additional certification requirements 

should be considered. 

EPA solicits comments on the 

availability of laboratory capacity to 

perform TTHM and HAA5 analyses for 

IDSE studies. 

VI. State Implementation 

This section describes the regulations 

and other procedures and policies States 

would have to adopt to implement the 

Stage 2 DBPR, if finalized as proposed 

today. States must continue to meet all 

other conditions of primacy in 40 CFR 

part 142. 

The SDWA establishes requirements 

that a State or eligible Indian Tribe must 

meet to assume and maintain primary 

enforcement responsibility (primacy) for 

its public water systems. These SDWA 

requirements include: (1) adopting 

drinking water regulations that are no 

less stringent than Federal drinking 

water regulations, (2) adopting and 

implementing adequate procedures for 

enforcement, (3) keeping records and 

making reports available on activities 

that EPA requires by regulation, (4) 

issuing variances and exemptions (if 

allowed by the State), under conditions 

no less stringent than allowed under the 

SDWA, and (5) adopting and being 

capable of implementing an adequate 

plan for the provision of safe drinking 

water under emergency situations. 

General rule implementation activities 

include notifying systems of rule 

requirements, updating internal and 

external databases, providing training 

and technical assistance, and reviewing 

(and, if necessary, approving) 

monitoring and other reports and plans. 

To receive primacy for the Stage 2 

DBPR, when final, States will be 

required to adopt the following new or 

revised requirements under their own 

regulations:

—Section 141.33(a) and (f), Record 

maintenance; 

—Section 141.64, MCLs for disinfection 

byproducts; 

—Subpart L, Disinfectant Residuals, 

Disinfection Byproducts, and 

Disinfection Byproduct Precursors; 

—Subpart O, Consumer Confidence 

Reports; 

—Subpart Q, Public Notification of 

Drinking Water Violations; 

—Subpart U, Initial Distribution System 

Evaluation; and 

—Subpart V, Stage 2B Disinfection 

Byproducts Requirements.

In addition to adopting basic primacy 

requirements specified in 40 CFR part 

142, States are required to address 

applicable special primacy conditions. 

Special primacy conditions pertain to 

specific regulations where 

implementation of the rule involves 

activities beyond general primacy 

provisions. The purpose of these special 

primacy requirements in today’s 

proposal is to ensure State flexibility in 

implementing a regulation that: (1) 

Applies to specific system 

configurations within the particular 

State and (2) can be integrated with a 

State’s existing Public Water Supply 

Supervision Program. States must 

include these rule-distinct provisions in 

an application for approval or revision 

of their program. These primacy 

requirements for implementation 

flexibility are discussed in the following 

section. 

A. State Primacy Requirements for 

Implementation Flexibility 

To ensure that a State program 

includes all the elements necessary for 

an effective and enforceable program 

within that State under today’s rule, a 

State primacy application must include 

a description of how the State will 

review IDSE reports and approve new or 

revised monitoring sites for long-term 

DBP compliance monitoring. If a State 

will use the authority to grant blanket 

waivers for IDSE requirements to very 

small systems, it must comply with the 

special primacy provision for granting 

such waivers. A State that intends to use 

the authority for addressing consecutive 

system monitoring requirements must 

include a description of how it intends 

to implement that authority. A State 

primacy application must also include a 

description of how the State will require 

systems to identify significant 

excursions.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49623

B. State Recordkeeping Requirements 

The current regulations in § 142.14 

require States with primacy to keep 

various records, including analytical 

results to determine compliance with 

MCLs, MRDLs, and treatment technique 

requirements; system inventories; State 

approvals; enforcement actions; and the 

issuance of variances and exemptions. 

The proposed Stage 2 DBPR requires 

that the State keep records related to 

any decisions made pursuant to the 

requirements in subparts U and V, plus 

copies of IDSE reports submitted by 

systems until those reports are reversed 

or revised in their entirety. Today’s 

proposal also includes a revision to the 

State recordkeeping requirements that 

requires States to maintain records of 

DBP monitoring plans submitted by 

public water systems until superceded 

by a new system monitoring plan. 

C. State Reporting Requirements 

EPA currently requires in § 142.15 

that States report information such as 

violations, variance and exemption 

status, and enforcement actions to EPA. 

The proposed Stage 2 DBPR will not 

add any additional reporting 

requirements. 

D. Interim Primacy 

On April 28, 1998, EPA amended its 

State primacy regulations at 40 CFR 

142.12 to incorporate the new process 

identified in the 1996 SDWA 

Amendments for granting primary 

enforcement authority to States while 

their applications to modify their 

primacy programs are under review (63 

FR 23362) (USEPA 1998j). The new 

process grants interim primary 

enforcement authority for a new or 

revised regulation during the period in 

which EPA is making a determination 

with regard to primacy for that new or 

revised regulation. This interim 

enforcement authority begins on the 

date of the complete primacy 

application submission or the effective 

date of the new or revised State 

regulation, whichever is later, and ends 

when EPA makes a final determination. 

However, this interim primacy authority 

is only available to a State that has 

primacy for every existing NPDWR in 

effect when the new regulation is 

promulgated. 

As a result, States that have primacy 

for every existing NPDWR already in 

effect may obtain interim primacy for 

this rule, beginning on the date that the 

State submits the application for this 

rule to EPA, or the effective date of its 

revised regulations, whichever is later. 

In addition, a State which wishes to 

obtain interim primacy for future 

NPDWRs must obtain primacy for this 

rule. 

E. IDSE Implementation 

As discussed in section V.J., many 

systems will be performing certain IDSE 

activities prior to their State receiving 

primacy. During that period, EPA will 

act as the primacy agency, but will 

consult and coordinate with individual 

States to the extent practicable and to 

the extent that States are willing and 

able to do so. In addition, prior to 

primacy, States may be asked to assist 

EPA in identifying and confirming 

systems that are required to comply 

with certain IDSE activities. Once the 

State has received primacy, it will 

become responsible for IDSE 

implementation activities. 

F. State Burden 

Section VII of today’s document 

contains an analysis of the burden that 

this rule will place on States in 

receiving primacy and implementing 

this rule. 

G. Request for Comment 

EPA requests comment on the State 

implementation requirements including 

the special primacy requirements. 

VII. Economic Analysis 

This section summarizes the Health 

Risk Reduction and Cost Analysis 

(HRRCA) in support of the Stage 2 DBPR 

as required by section 1412(b)(3)(C) of 

the 1996 SDWA. In addition, under 

Executive Order 12866, Regulatory 

Planning and Review, EPA must 

estimate the costs and benefits of the 

Stage 2 DBPR in an Economic Analysis 

(EA). EPA has prepared an EA to 

comply with the requirements of this 

order and the SDWA Health Risk 

Reduction and Cost Analysis (HRRCA) 

(USEPA 2003i). SDWA (Section 1412 

(b)(4)(C)) also requires the Agency to 

determine that the benefits of the 

promulgated rule would justify the costs 

of compliance. The proposed EA is 

available in the docket and is also 

published on the Agency’s web site: 

http://www.epa.gov/edocket.

It is important to note that the 

regulatory options considered by the 

Agency are the direct result of an 

Advisory Committee process that 

involved various drinking water 

stakeholders. More information on this 

process is discussed in sections II and 

V of today’s preamble.

In order to analyze both benefits and 

costs of the proposed rule and other 

regulatory alternatives considered by 

the Agency, EPA relied on several data 

sources to understand DBP occurrence, 

an analytical model to predict treatment 

changes and changes in DBP 

occurrence, and input and analysis from 

expert technical review panels to assist 

with model validation and technology 

selection. A brief description of the 

process is outlined in section VII.E. but 

a more detailed explanation of the 

analytical process is in the EA for the 

proposed Stage 2 DBPR (USEPA 2003i). 

The Stage 2 DBPR economic impact 

analysis uses a model, (referred to as the 

Surface Water Analytical Tool or 

SWAT) and information collected under 

the Information Collection Rule to make 

predictions about finished water and 

delivered water DBP levels, as well as 

predicting technology changes 

necessary for systems to comply with 

rule alternatives. Specifically, SWAT 

estimates post-Stage 1 DBPR (pre-Stage 

2) and post-Stage 2 DBPR DBP levels 

and likely technology choices by the 

industry to achieve compliance. For 

smaller systems and for all ground water 

systems, expert panels considered 

occurrence data and current treatment 

technology specific to these systems and 

used this information to predict 

technology treatment changes that may 

result from this proposed rule. 

Both benefits and costs are presented 

as annualized values. The process 

allows comparison of cost and benefit 

streams that are variable over a given 

time period. The time frame used for 

both benefit and cost comparisons is 25 

years; approximately five years account 

for rule implementation and 20 years for 

the average useful life of the equipment. 

The Agency uses social discount rates of 

both three percent and seven percent to 

calculate present values from the stream 

of benefits and costs and also to 

annualize the present value estimates. 

The EA for the proposed rule (USEPA 

2003i) also shows the undiscounted 

stream of both benefits and costs over 

the 25 year analysis period. 

A. Regulatory Alternatives Considered 

by the Agency 

Today’s proposed Stage 2 DBPR 

represents the second of a set of rules 

that address public health risks from 

DBPs. The Stage 1 DBPR was 

promulgated to decrease average 

exposure to DBPs and associated health 

risks by focusing compliance on MCLs 

based on average concentrations of 

TTHM and HAA5 within the 

distribution system. Today’s proposed 

Stage 2 DBPR further reduces exposure 

to chlorinated DBPs by basing 

compliance on the LRAA of TTHM and 

HAA5 concentrations at each sampling 

point within the distribution system. 

Section V illustrated the LRAA concept 

and differences in the two compliance 

calculation methodologies. In addition,

49624 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

section V provided a comparison of the 

regulatory options considered. This 

subsection will summarize the 

comparison of options and subsection 

VII.B. will outline the exposure analyses 

that led EPA to propose the preferred 

option and will present the predicted 

national occurrence distributions that 

were used to quantify predicted 

exposure reductions from today’s 

proposed rule. A detailed discussion of 

EPA’s exposure analyses can be found 

in the Economic Analysis for the Stage 

2 DBPR (USEPA 2003i). 

There are two components in the 

Agency’s M–DBP regulatory 

development process that are 

particularly relevant to evaluation of 

options discussed in today’s proposal: 

(1) the data synthesis and evaluation 

resulting from the Information 

Collection Rule; and (2) the analysis and 

recommendations of the M–DBP 

Advisory Committee. Data from the 

Information Collection Rule were used 

with the SWAT model to estimate the 

national distributions of DBP 

occurrence. The Advisory Committee 

considered several questions during the 

negotiation process, including:

—What are the remaining health risks 

after implementation of the Stage 1 

DBPR? 

—What are approaches to addressing 

these risks? 

—What are the risk tradeoffs that need 

to be considered in evaluating these 

approaches? 

—How do the estimated costs of the 

approach compare to reductions in 

peak occurrences and overall 

exposure for that approach? How does 

this measure (ratio of costs to 

exposure reduction) compare among 

the approaches?

The Advisory Committee considered 

the DBP occurrence estimates and 

characteristics of these distributions to 

be important in understanding the 

nature of public health risks. Although 

the Information Collection Rule data 

were collected prior to promulgation of 

the Stage 1 DBPR, the data support the 

concept that a system could be in 

compliance with the Stage 1 DBPR 

MCLs of 0.080 mg/L and 0.060 mg/L for 

TTHM and HAA5, respectively, and yet 

have points in the distribution system 

with either periodically or consistently 

higher DBP levels (see section IV). 

Based on these findings, and in order 

to address disproportionate risk within 

distribution systems, the Advisory 

Committee discussed an array of options 

that would base compliance on 

exposure at specific sampling locations 

rather than on average exposures for the 

entire distribution system. These 

included options for determining 

compliance as an LRAA (requiring 

systems to meet the MCL at individual 

sampling locations as a running annual 

average) or as absolute maximums 

(requiring that no samples taken exceed 

the MCL concentration), in addition to 

a combination of these approaches. For 

example, the Advisory Committee 

reviewed the exposure reductions for a 

number of approaches based on 

different LRAA and absolute maximum 

incremental MCL levels, and 

combinations of an LRAA approach 

with a companion absolute maximum 

for a variety of different concentration 

levels. The Advisory Committee also 

evaluated the associated technology 

changes and costs for these alternatives. 

In the process of narrowing down 

alternatives based on this vast amount 

of information, the Advisory Committee 

primarily focused on four types of 

alternative rule scenarios illustrated 

next. 

Preferred Alternative 

—Long-term MCLs of 0.080 mg/L for 

TTHM and 0.060 mg/L for HAA5 as 

LRAAs. 

—Bromate MCL remaining at 0.010 mg/

L. 

Alternative 1 

—Long-term MCLs of 0.080 mg/L for 

TTHM and 0.060 mg/L for HAA5 as 

LRAAs. 

—Bromate MCL of 0.005 mg/L. 

Alternative 2 

—Long-term MCLs of 0.080 mg/L for 

TTHM and 0.060 mg/L for HAA5 as 

absolute maximums for individual 

measurements. 

—Bromate MCL remaining at 0.010 mg/

L. 

Alternative 3 

—Long-term MCLs of 0.040 mg/L for 

TTHM and 0.030 mg/L for HAA5 as 

an RAA. 

—Bromate MCL remaining at 0.010 mg/

L.

Figure VII–1 shows how compliance 

would be determined under each of the 

TTHM/HAA5 alternatives described and 

the Stage 1 DBPR for a hypothetical 

large surface water system. This 

hypothetical system has one treatment 

plant and measures TTHM in the 

distribution system in four locations per 

quarter (the calculation methodology 

shown would be the same for HAA5). 

Ultimately, the Advisory Committee 

recommended the Preferred Alternative 

in combination with an IDSE 

requirement. 

BILLING CODE 6560–50–P

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49625

The Preferred Alternative, coupled 

with the IDSE’s refocused sampling (see 

section V), was recommended by the 

Advisory Committee because this 

approach addresses the objective of 

reducing potential adverse reproductive 

and developmental health risks. It 

achieves this objective by controlling 

peak TTHM and HAA5 concentrations 

at sites throughout the distribution 

system without compromising microbial 

protection. At the same time, it will 

only require a few higher risk systems 

to face the cost of employing additional 

advanced technologies. While this 

alternative controls the occurrence of 

consistently high DBP levels, it is still 

possible that individual samples could 

exceed the MCL, and consumers could 

thus be exposed to higher DBP 

concentrations for some portion of the 

year. In addition, this alternative will 

further reduce average DBP levels as 

systems make changes to reduce these 

peak concentrations. Subsection VII.B. 

will show how today’s proposed 

requirements are predicted to decrease 

exposure risks. The benefits and costs of 

each alternative are presented in 

subsections VII.C. through VII.E.


EP18AU03.010</GPH>
49626 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

B. Rationale for the Proposed Rule 

Option 

DBP concentrations can be highly 

variable throughout a distribution 

system and over time at the same 

location in a distribution system 

(USEPA 2003o). The determination of 

compliance with an RAA under the 

Stage 1 DBPR requires a system to 

average all of their spatially-distributed 

samples collected in one quarter of the 

year and to combine this average 

concentration with the three prior 

quarterly averages determined by the 

system. Thus, the RAA-based standard 

allows utilities to average spatial and 

temporal variability in TTHM and 

HAA5 samples to determine 

compliance, as shown in figure VII–1. 

This allows lower results found, 

perhaps, nearer a water treatment plant 

to offset higher results that might be 

found at the ends of the distribution 

system. In addition, systems with 

multiple plants of differing water 

quality (either multiple surface water 

plants or surface and ground water 

plants) may have particular plant 

distribution system sampling locations 

with high DBPs that are offset by lower 

measurements observed in the portion 

of the distribution network served by 

other plants. 

Under the Stage 2 DBPR proposed 

today, TTHM and HAA5 MCLs will 

remain the same, but compliance will be 

based on a locational running annual 

average (LRAA) for each of the sampling 

sites in the distribution system. In 

addition, the IDSE requirement will 

increase the probability that the 

compliance sampling sites will capture 

the highest DBP levels in the 

distribution system. Thus, the reduction 

in DBP exposure from the Stage 1 DBPR 

to the proposed Stage 2 DBPR results 

from the revised requirements for 

compliance calculations combined with 

new compliance monitoring sites. 

EPA expects the Stage 2 DBPR, as 

proposed, will result in health benefits 

by reducing the estimated health risks 

associated with the following exposures:

—Individual TTHM/HAA5 occurrences 

significantly exceeding 0.080 mg/L 

and 0.060 mg/L; 

—Chronic exposures at individual 

distribution system locations that 

average more than 0.080 mg/L and 

0.060 mg/L; 

—Chronic exposures at all locations in 

the distribution system by reducing 

overall system average DBP 

concentrations; and 

—Chronic and peak exposures in 

consecutive systems (systems that 

purchase treated water from another 

system).

Under the Stage 1 DBPR, high DBP 

concentrations at specific locations in 

the distribution system could be masked 

by spatial and temporal averaging. As 

discussed in subsection VII.C, short 

term exposures resulting from these 

high concentrations may be of concern 

in regard to potential adverse 

reproductive and developmental health 

effects. Chronic exposures at locations 

having repeated high DBP 

concentrations may be of concern for 

cancer endpoints as well. The 

remainder of this subsection will 

illustrate how today’s proposed rule is 

expected to reduce ‘‘peak’’ and average 

exposures to address these health 

concerns. 

1. Reducing Peak Exposure 

EPA used Information Collection Rule 

data to estimate the reduction in 

exposure to DBP peaks resulting from 

the Stage 2 DBPR. Because the 

Information Collection Rule data 

represent pre-Stage 1 DBPR conditions, 

subsets of those plants already in 

compliance with the Stage 1 DBPR and 

Stage 2 DBPR were used to estimate preStage 2 and post-Stage 2 occurrence 

respectively. By comparing these 

subsets of data, EPA estimated that 

approximately 69% of plant locations 

having TTHM peaks greater than 0.080 

mg/L remaining after the Stage 1 DBPR 

could be reduced through 

implementation of the Stage 2 DBPR. 

EPA conducted this additional peak 

reduction analysis only for TTHMs and 

not HAA5s because current 

epidemiological data only considers the 

association between TTHM exposure 

and adverse health impacts (see 

subsection VII.C). Additional 

information on reduction of peak 

exposures can be found in section 5.4.1 

of the Economic Analysis (USEPA 

2003i). EPA recognizes that temporal 

and spatial variability in systems that 

need to install treatment to comply with 

the Stage 1 DBPR may be different than 

in those that do not, perhaps due to low 

source water TOC concentrations. 

However, EPA does not have data 

representing DBP levels post-Stage 1. 

EPA requests comment on its approach 

of using data from plants in compliance 

with Stage 1 DBPR requirements 

without implementing additional 

treatment as a proxy for post-Stage 1 

DBP levels. 

2. Reducing Average Exposure 

To quantify the benefits of today’s 

proposed rule, EPA compared predicted 

post-Stage 2 DBPR occurrence and 

compared this to the predicted baseline 

concentrations after the Stage 1 DBPR to 

determine reductions in exposure 

resulting from the Stage 2 DBPR. The 

SWAT model was the main tool used in 

this analysis. SWAT results were used 

directly for medium and large surface 

water systems. For small surface water 

systems and all ground water systems. 

Adjustments were made to the SWAT 

results to account for different 

percentages of plants changing 

technology to meet Stage 2 DBPR 

requirements. The Economic Analysis 

for today’s proposed rule (USEPA 2003i) 

provides an in-depth discussion of this 

analysis. 

Table VII–2 shows the reduction in 

average plant-level TTHM and HAA5 

concentrations estimated to result from 

the Stage 2 DBPR. EPA expects average 

DBP levels to decline by 4.7 percent for 

all surface water systems. DBP averages 

are expected to decline by 2.2 percent 

for all large ground water systems and 

1.7 percent for all small ground water 

systems. These estimates include both 

systems already in compliance with the 

Stage 2 DBPR and systems making 

treatment changes to comply with the 

rule. The Agency uses these national 

average reductions to quantify the 

primary benefit of this rule which is the 

estimated range of reduction in bladder 

cancer cases nationally. Systems making 

treatment changes to comply with the 

rule will experience significantly greater 

estimated average reductions than the 

national average for all systems. Chapter 

5 of the EA (USEPA 2003i) includes a 

more detailed discussion of this 

analysis.

TABLE VII–2.—REDUCTION IN AVERAGE DBP LEVELS FROM PRE-STAGE 2 TO POST-STAGE 2 (ALL PLANTS) 

Source water 

System size 

(population 

served) 

Average plant-level TTHM concentrations 

(μg/L) 

Average plant-level HAA5 concentrations 

(μg/L) 

Pre-stage 2 Post-stage 

2 

Percent 

reduction Pre-stage 2 Post-stage 2 

Percent 

reduction 

SW ....................................................... ≤ 10,000 35.5 33.8 4.7 25.0 23.8 4.7 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49627

TABLE VII–2.—REDUCTION IN AVERAGE DBP LEVELS FROM PRE-STAGE 2 TO POST-STAGE 2 (ALL PLANTS)—Continued

Source water 

System size 

(population 

served) 

Average plant-level TTHM concentrations 

(μg/L) 

Average plant-level HAA5 concentrations 

(μg/L) 

Pre-stage 2 Post-stage 

2 

Percent 

reduction Pre-stage 2 Post-stage 2 

Percent 

reduction 

> 10,000 35.5 33.8 4.7 25.0 23.8 4.7 

GW ....................................................... ≤ 10,000 16.0 15.6 2.2 8.5 8.3 2.2 

10,000 16.2 16.0 1.7 8.6 8.5 1.7 

Note: Due to rounding, percent reductions calculated from data in the tables may differ from the actual values presented here 

Source: Economic Analysis (USEPA 2003i) Exhibit 5.22b 

C. Benefits of the Proposed Stage 2 

DBPR 

As described previously, the Stage 2 

DBPR is expected to reduce both peak 

and long-term exposure to DBPs, 

thereby reducing the potential risk of 

both adverse reproductive and 

developmental health effects and 

bladder cancer. As discussed in section 

III of this preamble, both 

epidemiological and toxicological 

evidence suggest a possible increased 

risk for pregnant women and their 

fetuses who are exposed to DBPs in 

drinking water. The Agency believes 

and the Advisory Committee concluded 

that the weight of evidence is enough to 

take regulatory action to help address 

the potential reproductive and 

developmental endpoints in the Stage 2 

DBPR. However, data are not available 

at this time to conduct a traditional 

quantitative risk assessment. Instead, 

the benefits from reducing most 

reproductive and developmental risks 

are discussed qualitatively in this 

preamble. For one endpoint, fetal loss, 

the Agency provides an illustrative 

calculation to explore the implications 

of some published results for potential 

benefits associated with reducing fetal 

losses that may be attributable to certain 

DBP exposures. 

In addition to achieving greater 

protection from possible adverse 

reproductive and developmental health 

effects, the rule may provide additional 

reduction in bladder cancer cases as the 

overall level of DBPs in distribution 

systems nation-wide decreases. The 

Agency estimated and monetized the 

potential benefits from reduction in 

bladder cancers resulting from this rule. 

Reductions in bladder cancer (including 

both fatal and non-fatal cases) provide a 

range of annualized present value 

benefits from $0 to $986 million using 

a three percent discount rate ($0 to $854 

million using a seven percent discount 

rate) depending on the risk level 

assumed. These estimates are based on 

the assumption that the percent 

reductions in TTHM and HAAs will 

correspond to the percent reductions in 

bladder cancer risk attributed to 

populations receiving chlorinated 

drinking water as indicated by various 

epidemiology studies (USEPA 1998a). 

Zero is included in this range because 

of the inconsistent evidence regarding 

the association between exposure from 

DBPs and cancer. 

Other regulatory alternatives 

considered by the FACA committee and 

the Agency could provide greater 

benefits but with greater technology cost 

implications. Table VII–3 presents 

benefits estimates of the proposed Stage 

2 DBPR using two population 

attributable risks derived from 

published studies (2% and 17%) and 

assuming there is a causal link between 

DBP exposure and bladder cancer. In 

subsection VII.G., Table VII–14 shows 

potential benefits of all regulatory 

alternatives considered by the Agency. 

BILLING CODE 6560–50–P

49628 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

It is important to note that the 

monetized benefits only reflect 

estimated benefits from reductions in 

bladder cancer. As shown in subsection 

VII.C.1.and in Table VII–3, there may be 

significant nonquantifiable benefits 

associated with regulating DBPs in 

drinking water. Were EPA able to 

quantify some of the currently 

nonquantifiable health effects and other 

benefits potentially associated with DBP 

regulation, monetized benefits estimates 

could be significantly higher than what 

is shown in the table. A complete 

discussion of how EPA calculated the 

risks and the corresponding health 

benefits potentially associated with 

exposure to DBPs in drinking water can 

be found in the Stage 2 DBPR EA 

(USEPA 2003i). 

For additional perspective EPA used 

updated cancer risk factors for four 

DBPs for which we have toxicological 

data. Table III–3 (see section III of this 

preamble) shows the estimated preStage 2 concentrations of these four 

compounds and the estimated number


EP18AU03.028</MATH>
Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49629

2Use of unadjusted PAR estimates has the effect 

of removing the adjustments for known 

confounders, however, EPA believes the unadjusted 

estimates are adequate for purposes of the 

illustrative calculations presented here.

3The negative lower 95% confidence intervals for 

all three studies was truncated at zero.

of people exposed to them. The Agency 

used these four DBPs to calculate an 

alternative baseline number of annual 

pre-Stage 2 cancer cases. The 

calculations use the linearized 

multistage model and predict 37 cases 

for the ED10 risk factors and 87 cases for 

the LED10 risk factors. The ED10 risk 

factors (also known as the maximum 

likelihood estimate) are based on the 

estimated dose that the model predicts 

will result in a carcinogenic response in 

10 percent of the subjects, while LED10

risk factors correspond to the lower 95% 

confidence bound on the dose that the 

model predicts will result in a 

carcinogenic response in 10% of the 

subjects (LED10 is EPA’s more 

conservative and more commonly used 

expression of toxicologically based 

cancer risk). Assuming that DBP risk 

reductions for Stage 2 for the entire 

population average 4.2% (corresponding 

to the reduction in average TTHM 

levels), Stage 2 cancer cases avoided 

based on the toxicological data range 

from 1.7 to 4.0 cases per year. Section 

5.2.2.2 of the Economic Analysis 

(USEPA 2003i) presents a more detailed 

basis for the derivation of these 

estimates. It is important to note that 

these estimates do not include risks 

from dermal or inhalation exposure nor 

do they account for many other DBPs (or 

the mixture of DBPs seen in actual 

PWSs) for which occurrence or 

toxicological risk data do not exist. 

1. Non-Quantifiable Health and NonHealth Related Benefits 

Although there are significant 

monetized benefits that may result from 

this rule from the reduction in bladder 

cancer, other important potential 

benefits of this rule are not quantified 

including potential reductions in 

adverse reproductive and 

developmental effects and other 

cancers. 

The primary purpose of the Stage 2 

DBPR is to address potential adverse 

reproductive and developmental health 

effects that might be associated with 

DBP exposure. EPA concludes that, ‘‘the 

epidemiologic data, although not 

conclusive, are suggestive of potential 

developmental, reproductive, or 

carcinogenic health effects in humans 

exposed to DBPs’’ (Simmons et al 2002). 

EPA does not believe the available 

evidence provides an adequate basis for 

quantifying potential reproductive/

developmental risks. Nevertheless, 

given the widespread nature of exposure 

to DBPs and the priority our society 

places on reproductive/developmental 

health, and the large number of fetal 

losses experienced each year in the U.S. 

(nearly 1 million (Ventura et al. 2000)), 

we believe it is important to provide 

some quantitative indication of the 

potential risk suggested by some of the 

published results on reproductive/

developmental endpoints, despite the 

absence of certainty regarding a causal 

link between disinfection byproducts 

and these risks. To do this, we have 

adapted illustrative PAR calculations 

from several studies on the relationship 

between chlorinated water exposure and 

fetal loss and applied these to national 

statistics on annual incidence of fetal 

loss.

Specifically, we calculate the 

unadjusted population attributable risk 

associated with each of the three 

distinct population-based 

epidemiological studies of fetal loss 

published: Waller et al. 2001, King et al. 

2000a, and Savitz et al. 1995. All three 

are high quality studies that have 

sufficient sample sizes and high 

response rates, adjust for known 

confounders 2, and have exposure 

assessment information from water 

treatment data, residential histories, and 

THM measurements. Because the 

populations in these three studies 

appear to have TTHM exposures 

significantly greater than those of the 

general U.S. population, we have 

chosen to scale the results using 

Information Collection Rule data to 

allow us to derive population 

attributable risks that may be more 

relevant to the general U.S. population 

(USEPA 2003i).

These three studies (using unadjusted 

data to allow for comparability, and 

scaled to the TTHM levels reported in 

the Information Collection Rule data 

base) yield median PARs of 0.4%, 1.7%, 

and 1.7% (with 95% confidence 

intervals for each of the studies of 0 to 

4%) 3. Using the prevalence of fetal loss 

reported by CDC, the median PARs for 

these three studies suggest that the 

incidence of fetal loss attributable to 

exposure to chlorinated drinking water 

could range from 3,900 to 16,700 

annually. As part of the analysis to 

evaluate potential reduction in fetal loss 

for the Stage 2 DBPR, EPA assumed that 

reductions in risk are proportional to 

the 28 percent reductions in the number 

of locations having one or more 

quarterly TTHM measurements that 

exceed the study population cut-offs 

(>75 to >81 ug/l, depending on study). 

This analysis implies that a range of 

1,100 to 4,700 fetal losses could be 

avoided per year as a result of the Stage 

2 rule.

Caution is required in interpreting the 

numbers because many experts 

recommend that population attributable 

risk analysis should not be conducted 

unless causality has been established. 

Causality has not been established 

between exposure to disinfection 

byproducts and fetal loss. The estimates 

presented here are not part of EPA’s 

quantitative benefits analysis, and the 

ranges are not meant to suggest upper 

and lower bounds. Rather, they are 

intended to illustrate quantitatively the 

potential risk implications of some of 

the published results. 

EPA has not monetized the value of 

potential reductions in fetal loss, but 

recognizes that there is a significant 

value associated with improvements in 

reproductive and developmental health. 

In the absence of valuation studies 

specific to the health endpoints of 

concern, the Agency typically draws 

upon existing studies of similar health 

endpoints to estimate benefits. The 

‘‘transfer’’ of the results of these studies 

to value similar health endpoints must 

be done carefully and methodically, 

controlling for differences in the health 

endpoints and in the relevant 

populations. Some researchers have 

attempted to transfer values using 

sophisticated analytical techniques such 

as preference calibration methods (e.g., 

Smith et al. 2002). Regardless of the 

approach used, ‘‘benefit transfer’’

requires systematic comparison of the 

differences in the health effects in the 

studies and those resulting from the 

regulation. Application of benefit 

transfer leads to a detailed qualitative 

examination of the implications of using 

those studies and potentially to 

empirical adjustments to the results of 

the existing studies. 

The Agency is investigating further 

work specific to the case of fetal loss 

valuation. One possible area of further 

research is the value that prospective 

parents attach to reducing risks during 

pregnancy. In this regard, the 

substantial lifestyle changes that 

prospective parents often undertake 

during pregnancy suggests that reducing 

these kinds of risks is of value. A second 

possible area of further investigation 

would be work on benefit transfer 

methodologies that address how 

existing studies can inform the 

estimation of the benefits of reduced 

fetal loss. 

EPA has not monetized the potential 

reductions in fetal loss. Without more 

information and discussion on these 

subjects the Agency cannot fully 

consider and describe the implications 

of relying upon existing studies.

49630 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

However, research on valuation and 

benefit transfer continues to progress 

and the Agency anticipates new 

research and future efforts to value 

reproductive and developmental 

endpoints. 

EPA was also unable to quantify or 

monetize the benefit from potential 

reductions in other cancers, such as 

colon and rectal, that may result from 

this rule. Both toxicology and 

epidemiology studies indicate that other 

cancers may be associated with DBP 

exposure but currently there is not 

enough data to quantify or monetize 

these cancer risks. 

Other potential non-health related 

benefits not quantified or monetized in 

today’s proposed rule include reduced 

uncertainty about becoming ill from 

consumption of DBPs in drinking water, 

the ability for some treatment 

technologies to eliminate or reduce 

multiple contaminants, and monitoring 

changes that will ensure that systems 

can effectively measure their DBP levels 

resulting in greater equity in protection 

from DBPs. First, the reduced 

uncertainty concept depends on several 

factors including consumer’s degree of 

risk aversion, their perceptions about 

drinking water quality (degree to which 

they will be affected by the regulatory 

action), and the expected probability 

and severity of human health effects 

associated with DBPs in drinking water. 

This effect could be positive or negative 

depending on whether knowledge of the 

rule decreases or increases their concern 

about DBPs in drinking water and 

potentially associated health effects.

Another nonquantified potential 

benefit is the impact of technology 

selection to address DBPs on a system’s 

ability to address other contaminants. 

For example, membrane technology 

(depending on pore size), can be used to 

lower DBP formation but it can also 

remove other contaminants that EPA is 

in the process of regulating or 

considering regulating. Therefore, by 

installing membrane technology, a 

system may not have to make new 

capital improvement to comply with 

future regulations. 

Last, today’s proposed rule makes 

changes to Stage 1 monitoring 

requirements. The IDSE monitoring 

provision of the proposed Stage 2 DBPR 

will help systems identify locations to 

conduct their routine monitoring to 

capture high DBP occurrence levels. 

Also, the proposed Stage 2 DBPR will 

prevent a system from conducting 

sampling designed to avoid monitoring 

when DBP formation is generally higher. 

For example, the Stage 1 DBPR required 

systems to take quarterly samples but 

samples could conceivably be taken in 

December (4th quarter) and January (1st 

quarter) when the waters in the 

distribution system are colder and DBP 

formation generally lower. The 

proposed Stage 2 DBPR addresses this 

issue by requiring that the samples must 

be taken about 90 days apart. The 

benefits of these provisions include the 

greater certainty that health protection 

is actually achieved because it is more 

likely that a system’s high DBP levels 

will be identified. In addition, the rule 

will reduce variability in the DBP levels 

throughout the distribution system, 

ensuring greater equity in public health 

protection. 

2. Quantifiable Health Benefits 

Although DBPs in drinking water 

have been associated with noncancerous health effects discussed 

previously, the quantified benefits that 

result from today’s rule are associated 

only with estimated reductions in DBPrelated bladder cancer. A complete 

discussion of risk assessment 

methodology and assumptions can be 

found in Chapter 5 of the Stage 2 DBPR 

Economic Analysis (USEPA 2003i). 

Section III of this preamble also 

discusses the health effects that have 

been associated with DBP exposure. 

The annualized present value benefits 

for reductions in bladder cancer that are 

the result of today’s rule for both 

community water system (CWS) and 

non-transient non-community water 

systems (NTNCWSs) range from $0 to 

$986 million using a three percent 

discount rate ($0 to $854 million using 

a seven percent discount rate). Overall, 

the Stage 2 DBPR may reduce on 

average 0 to 182 bladder cancer cases 

per year. 

The lower estimate of zero is included 

because of inconsistent evidence 

regarding the association between 

exposure to DBPs and cancer. The upper 

estimate of monetized benefits and cases 

avoided is based on a population 

attributable risk (PAR) of 17 percent. 

Table VII–3 also presents monetized 

benefits based on a PAR value of 2%. 

The PAR estimates are derived from an 

analysis of five epidemiological studies 

which indicate that perhaps 2 to 17 

percent of bladder cancers may be 

attributable to DBP exposure. These 

PAR estimates are described in more 

detail in section III of today’s document. 

These are the same PAR values that EPA 

used in the Stage 1 DBPR benefits 

analysis, as discussed in the Regulatory 

Impact Analysis for the Stage 1 DBPR 

(USEPA 1998f). Table VII–3 shows the 

estimated benefits associated with 

bladder cancer reduction as a result of 

the proposed rule. Table VII–4 

summarizes the mean, median and 

confidence intervals used to value 

reductions in bladder cancer. 

To calculate the total value of benefits 

derived from reductions in bladder 

cancer cases as a result of the Stage 2 

DBPR, a stream of estimated monetary 

benefits is calculated by combining the 

annual cases avoided with valuation 

inputs using Monte Carlo simulation. 

Use of a Monte Carlo simulation allows 

the characterization of uncertainty 

around final modeling outputs based on 

the uncertainty underlying the various 

valuation inputs. The Stage 2 DBPR 

benefits model uses distributions of 

value of statistical life (VSL), 

willingness-to-pay (WTP), and income 

elasticity values to attribute monetary 

values (with uncertainty bounds) to the 

number of bladder cancer cases avoided. 

Several of the inputs needed in the 

benefit analysis, such as the VSL and 

WTP estimates, are based on older 

studies that were updated to current 

dollar values. In addition, both the VSL 

and WTP values are dependent on 

income levels. Therefore, these values 

also have to be adjusted for increases in 

real income growth from when the 

studies were conducted. The valuation 

inputs and an explanation of the update 

factors used to bring these values to 

current price levels and discussed in the 

following two sections. 

Valuation inputs. In order to monetize 

the benefit from the bladder cancer 

fatalities, EPA applied a VSL estimate to 

the cancer cases that result in mortality. 

EPA assumed a 26 percent mortality rate 

for bladder cancer (USEPA 1999d). The 

Agency uses a distribution of VSL 

values which are based on 26 wage-risk 

studies. The mean VSL value from these 

studies is $4.8 million in 1990 dollars. 

The mean value reflects the best 

estimate in the range of plausible values 

reflected by the 26 studies. A more 

detailed discussion of these studies and 

the VSL estimate can be found in EPA’s 

Guidelines for Preparing Economic 

Analyses (USEPA 2000b). 

The VSL represents the value of 

reducing the risk of a premature death. 

This valuation, however, does not take 

into account the medical costs 

associated with the period of illness 

(morbidity increment) leading up to a 

death. In its review of the Arsenic Rule, 

the Science Advisory Board (SAB) 

suggested that the appropriate measure 

to use in valuing the avoidance of the 

morbidity increment is the medical cost 

attributable to a cancer case (USEPA 

2001e). Based on available medical data, 

EPA estimates the medical costs for a 

fatal bladder cancer case to be $93,927 

at a 1996 price level (USEPA 1999d). 

This medical cost value (updated to 

2000 price levels) is applied as a point

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49631

4SAB included the following in its report on 

arsenic to emphasize this difference: ‘‘An important 

point is that the time to benefits from reducing 

arsenic in drinking water may not equal the 

estimated time since first exposure to an adverse 

effect. A good example is cigarette smoking: the 

latency between initiation of exposure and an 

increase in lung cancer risk is approximately 20 

years. However, after cessation of exposure, risk for 

lung cancer begins to decline rather quickly. A 

benefits analysis of smoking cessation programs

Continued

estimate to each fatal case of bladder 

cancer in the benefits model.

A review of the available literature 

did not reveal any studies that 

specifically measured the WTP to avoid 

risks of contracting nonfatal cases of 

bladder cancer. Instead, two alternates 

were used, the WTP to avoid the risk of 

contracting a case of curable lymph 

cancer (lymphoma) and the WTP to 

avoid a case of chronic bronchitis. The 

SAB suggested this approach in their 

review of the Arsenic Rule (USEPA 

2001e). The median risk-risk trade-off 

for a curable case of lymphoma was 

equivalent to 58.3 percent of the risk 

attributed to reducing the chances of 

facing a sudden death and are derived 

from the Magat et al. study (1996). 

Therefore, the Agency applies the 58.3 

percent to the VSL distribution to derive 

a range of value for non-fatal cancers 

with a mean WTP value of $2.8 million 

($4.8 million * 58.3 percent) at a 1990 

price level. The WTP for avoiding a case 

of chronic bronchitis is based on the 

same methodology used for the Stage 1 

DBPR (see Stage 2 DBPR EA (USEPA 

2003i) for a complete discussion). The 

estimate is based on a lognormal 

distribution that uses the risk-dollar 

tradeoff estimate and has a mean of 

$587,500, standard deviation of 

$264,826, and a maximum value of $1.5 

million at 1998 price values. 

Update factors. All valuation 

parameters must be updated to the same 

price level so comparisons can be made 

in real terms. Values for VSL, WTP, and 

the morbidity increment used in the 

model are updated based on adjustment 

factors derived from Bureau of Labor 

Statistics (BLS) consumer price index 

(CPI) data so that each represents a year 

2000 price level. Table VII–4 

summarizes these updates.

Although the price level (year 2000) is 

held constant throughout the benefits 

model, projections of benefits in future 

years are subject to income elasticity 

adjustments. Income elasticity 

adjustments represent changes in 

valuation in relation to changes in real 

income. For fatal cancers, the Agency 

used a triangular distribution with a 

central estimate of 0.40 (low end: 0.08; 

high end:1.00) to represent the 

uncertainty of the income elasticity 

value. For non-fatal cancers, the Agency 

uses a triangular distribution with a 

central estimate of 0.45 (low end: 0.25; 

high end: 0.60). These distributions are 

used as assumptions in the Monte Carlo 

simulation to further characterize 

uncertainty in benefits estimates. 

In order to apply the income elasticity 

values in the model, they are combined 

with projections of real income growth 

over the time frame for analysis. 

Population and real gross domestic 

product (GDP) projections are combined 

to calculate per-capita real GDP values. 

A more detailed discussion of these 

adjustments is in Chapter 5 of the EA 

(USEPA 2003i). 

The development of cancer due to 

exposure to environmental carcinogens 

involves a complex set of processes that 

are not well-understood for most 

specific substances. In general, however, 

the development of cancer involves 

some time period, usually referred to as 

the latency period, between the initial 

exposure and the manifestation of 

disease. Defining a latency period is 

highly uncertain because the mode of 

action for most chemical contaminants 

are poorly understood. Latency periods 

in humans often involve many years, 

even decades. 

EPA recognizes that despite 

uncertainties in the latency period 

associated with different types of 

carcinogens, it is unlikely that all cancer 

reduction benefits would be realized 

immediately upon exposure reduction. 

If it is assumed that lower risk is 

attained immediately upon reduction in 

exposure, this would tend to 

overestimate the benefits. On the other 

hand, assuming that no risk reduction 

occurs for some period of time following 

exposure reduction may lead to an 

underestimation of the benefits. There 

will likely be some transition period as 

individual risks become more reflective 

of the new lower exposures than the 

past higher exposures. 

Recently, the Arsenic Rule Benefits 

Review Panel of the EPA Science 

Advisory Board (SAB) addressed this 

issue in detail and provided some 

guidance for computing benefits to 

account for this transition period 

between higher and lower steady-state 

risks (USEPA 2003s). The Arsenic Rule 

Benefits Review Panel coined the term 

‘‘cessation-lag’’ to emphasize the focus 

on the timing of the attenuation of risk 

after reduction in exposures to avoid 

confusion with the more traditional 

term of ‘‘latency’’ that reflects the 

increased risk 4 from the time of initial 

exposure.


EP18AU03.011</GPH>
49632 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

based on the observed latency would greatly 

underestimate the actual benefits.’’

Although the focus of the cessation 

lag discussion in the SAB review was on 

reducing levels of arsenic in drinking 

water, much of their consideration of 

this issue has more general applications 

beyond just the arsenic issue at hand. In 

particular, SAB noted the following: 

• The same model should be used to 

estimate the time pattern of exposure 

and response as is used to estimate the 

potency of the carcinogen. 

• If possible, information about the 

mechanism by which cancer occurs 

should be used in estimating the 

cessation lag (noting that late-stage 

mechanisms in cancer formation imply 

a shorter cessation lag than early stage 

mechanisms). 

• If specific data are not available for 

characterizing the cessation lag, an 

upper bound for benefits can be 

provided based on the assumption of 

immediately attaining steady-state 

results. 

• In the absence of specific cessation 

lag data, other models should be 

considered to examine the influence of 

the lag. 

Following the release of the SAB 

report on arsenic, EPA initiated an effort 

to explore approaches to including the 

cessation lag in modeling risk reduction 

and calculating benefits for the arsenic 

regulation. EPA recognized, however, 

that the concept of cessation lag is not 

only applicable to arsenic but to other 

drinking water contaminants having a 

cancer end-point as well. 

In response to the SAB cessation lag 

recommendations, EPA has: 

• Conducted a study using data on 

lung cancer risk reductions following 

cessation of smoking that resulted in the 

January 2003 report Arsenic in Drinking 

Water: Cessation Lag Model (USEPA 

2003s). 

• Conducted an expert scientific peer 

review of that draft report. 

• Initiated development of general 

criteria for incorporating cessation lag 

modeling in benefits analyses for other 

drinking water regulations. 

In the effort to develop a cessation lag 

model specific to DBPs, EPA reviewed 

the available epidemiological literature 

for information relating to the timing of 

exposure and response, but could not 

identify any studies that were adequate, 

alone or in combination, to support a 

specific cessation lag model for DBPs in 

drinking water. Thus, in keeping with 

the SAB recommendation to consider 

other models in the absence of specific 

cessation lag information, EPA explored 

the use of information on other 

carcinogens that could be used as a 

indicator to characterize the influence of 

cessation lag in calculating benefits. The 

carcinogen for which the most extensive 

database was available for 

characterizing cessation lag was for 

cigarette smoking. EPA examined 

several extensive epidemiological 

studies on the comparison of the risks 

of adverse health effects, including lung 

cancer, for smokers and former smokers. 

EPA selected the Hrubek and 

McLaughlin (1997) study as the most 

appropriate study for development of a 

statistical model of disease response to 

smoking cessation. This was a 

comprehensive study involving a 26-

year follow-up of almost 300,000 U.S. 

male military veterans. More detail 

about this study and how it is applied 

to estimate the cessation lag can be 

found in Chapter 5 of the EA (USEPA 

2003i) and the cessation lag document 

(USEPA 2003s).

The smoking cessation lag data imply 

that the majority of the potential steady 

state cases avoided occur within the 

first several years, but with diminishing 

incremental increases in later years. For 

example, the cessation lag model 

indicates that approximately 40 percent 

of the steady-state cases avoided are 

achieved by the end of the second year, 

with 70 percent achieved by the end of 

the fifth year, and approximately 80 

percent by the tenth year. By the 

twentieth year, 90 percent of the steady 

state cases are avoided. 

EPA recognizes that there are several 

factors that contribute to the uncertainty 

in the application of the specific 

cessation lag model used in the 

estimation of the benefits of the 

proposed Stage 2 regulation. A key 

factor to consider in assessing this 

impact is the likely mode of action of 

DBPs in eliciting bladder cancer versus 

the mode of action of tobacco smoke in 

producing lung cancer, and in particular 

whether they behave as initiators or 

promoters of the carcinogenic process. 

As discussed in the SAB report and the 

EPA Cessation Lag report (USEPA 

2001e, USEPA 2003s), carcinogens that 

act solely or primarily as initiators 

would tend to show a longer cessation 

lag (lower rate of risk reduction 

following reductions in exposure) than 

carcinogens that act solely or primarily 

as promoters. The available information 

on tobacco smoke and lung cancer 

suggests that it involves a mixture of 

both initiators and promoters, and 

therefore the cessation lag derived from 

smoking data is expected to reflect the 

combined influence of these divergent 

mechanisms. There are no data available 

on the mechanism of action for DBPs 

and bladder cancer; indeed the specific 

carcinogenic agent(s) present in 

disinfected water responsible for the 

observed effect have not been identified. 

The use of the tobacco smoke cessation 

lag model reflecting a mixture of 

initiators and promoters would be 

expected to attenuate a possible bias in 

either direction if the DBPs responsible 

for bladder cancer are acting 

predominately as either initiators or 

promoters. 

Another factor to consider is that the 

cessation lag model used is based upon 

exposure to tobacco smoke where lung 

cancer is the end-point but is being 

applied to exposure to disinfection byproducts where the end-point is bladder 

cancer. Of concern here is that there is 

a more direct correlation between 

inhalation and the site of cancer for 

smoking than there is for ingestion and 

inhalation of drinking water and the 

sites of cancer for DBP exposure. 

Unfortunately, EPA does not have data 

on which to develop a cessation lag 

model using data specific to how 

changes in DBP exposures affect the 

risks of developing bladder cancer. 

Another divergence, and perhaps the 

most important, between the smoking 

model and the DBP application is that 

the smoking model is based on complete 

cessation of exposure, whereas in the 

case of DBP exposure is only being 

reduced. In some water systems the 

reduction is only 10 percent, whereas in 

others it may be as high as 60 percent, 

with an average of approximately 30%. 

This moderate reduction in exposure 

may prevent full DNA repair, which 

some scientists interpret as the basis for 

the short cessation lag associated with 

smoking. 

Currently, smoking is the only 

contaminant for which enough data 

exist to estimate a cessation lag. In the 

absence of a reliable cessation lag model 

based specifically on DBPs and bladder 

cancer, EPA used the cessation lag 

model based on smoking to provide a 

means of estimating the rate at which 

bladder cancer risk in the exposed 

population falls from the pre-Stage 2 

levels to the post-Stage 2 levels. 

However, this model is derived from 

data involving notable differences from 

DBPs in drinking water, including 

different cancer sites (lung versus 

bladder), different exposure pathways 

(inhalation versus a combination of 

ingestion, inhalation and dermal), 

different risk levels, and, perhaps most 

importantly, complete cessation for 

smoking versus small exposure 

decreases for DBPs. For these reasons, 

the extent to which the smoking / lung 

cancer model is directly transferable to 

DBP / bladder cancer is uncertain. It is 

not possible to know, however, whether 

and to what degree the tobacco smoke

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cessation lag model either over-states or 

under-states the rate at which 

population risk reduction for bladder 

cancer occurs following DBP exposure 

reductions. 

EPA is currently examining the 

recently published meta-analysis by 

Villanueva et al. (2003) to determine if 

the information provided on increases 

in risk as a function of duration of 

exposure can provide any insight on 

how reductions in risk over time might 

occur following reductions in exposure. 

Villanueva et al. (2003) demonstrated 

that the risk associated with chlorinated 

drinking water and bladder cancer are 

related to exposure duration. 

Specifically, they estimated a unit 

increase in the odds ratio of 1.006 per 

year (95% CI of 1.004 to 1.009). The 

model suggests a cumulative odds ratio 

of 1.13 after 20 years of exposure (95% 

CI of 1.08 to 1.20), and 1.27 (95% CI of 

1.17 to 1.43) after 40 years. This result 

is consistent with most of the individual 

studies which do not show statistically 

significant risk increases until at least 

30–40 years of exposure. However, these 

studies provide indirect evidence only 

about the latency of potential effects. 

For perspective, it is important to note 

that the latency between initiation of 

exposure and an increase in lung cancer 

risk is approximately 20 years. As noted 

above, latency is not the same as the 

cessation lag. EPA is requesting 

comment on (a) the potential 

application of the Villanueva et al.

(2003) model to estimate reductions in 

bladder cancer risk that might 

accompany decreased exposure to DBPs 

as a result of the Stage 2 Rule; (b) the 

advantages and disadvantages of using 

the current approach—i.e., application 

of the smoking cessation lag model; and 

(c) suggestions for alternative data sets 

or approaches to characterize cessation 

lag. 

In addition to the delay in reaching a 

new steady-state level of risk reduction 

as a result of cessation lag effects, there 

is a delay in exposure reduction 

resulting from the Stage 2 DBPR 

implementation. In general, EPA 

assumes that a fairly uniform increment 

of systems will complete installation of 

new treatment technologies each year, 

with the last systems installing 

treatment by 2013. EPA recognizes that 

more systems may start in early or later 

years, but believes that a uniform 

schedule is a reasonable assumption. 

Appendix D of the EA presents detailed 

information regarding the rule activity 

schedule assumptions (USEPA 2003i). 

The delay in exposure reduction 

resulting from the rule implementation 

schedule is incorporated into the 

benefits model by adjusting the 

cessation lag weighting factor. For 

example, if ten percent of systems 

install treatment equipment (and start 

realizing reductions in cancer cases) in 

year one, only that portion of the cases 

are modeled to begin the cessation lag 

equilibrium process in that year. Thus, 

the resulting ‘‘weighted weighting 

factor’’ is higher relative to the base 

factor. Appendix E in the EA (USEPA 

2003i) presents detailed breakdowns of 

all weighting factor adjustments and 

resulting cancer cases avoided, by year, 

for each rule alternative based on the 

application of the cessation lag 

methodology. 

3. Benefit Sensitivity Analyses 

The Agency performed one other 

benefit sensitivity analysis which is 

included in the EA to allow for 

comparison with the benefit estimates 

calculated for the Stage 1 DBPR. This 

analysis assumes that there is not a 

cessation lag or latency adjustment 

associated with bladder cancer 

reductions that result from the rule. In 

this case, the analysis assumes that the 

steady state reduction in bladder cancer 

occurs immediately with rule 

implementation. This is the same 

methodology used to estimate the 

quantified benefits of the Stage 1 DBPR.

D. Costs of the Proposed Stage 2 DBPR 

In estimating the costs of today’s 

proposed rule, the Agency considered 

impacts on water systems (CWSs and 

NTNCWSs) and on States (including 

territories and EPA implementation in 

non-primacy States). EPA assumed that 

systems would be in compliance with 

the Stage 1 DBPR, which has a 

compliance date of January 2004 for 

ground water systems and small surface 

water systems and January 2002 for 

large surface water systems. Therefore, 

the cost estimate only considers the 

additional requirements that are a direct 

result of the Stage 2 DBPR. More 

detailed information on cost estimates 

are described later and a complete 

discussion can be found in Chapter 6 of 

the Stage 2 DBPR EA (USEPA 2003i) 

1. National cost estimates 

EPA estimates that the mean 

annualized cost of the proposed rule 

ranges from approximately $59.1 

million using a three percent discount 

rate to $64.6 million using a seven 

percent discount rate. Drinking water 

utilities will incur approximately 98 

percent of the rule’s costs. States will 

incur the remaining rule cost. Tables 

VII–5 a and b summarize the total 

annualized cost estimates for the 

proposed Stage 2 DBPR. In addition to 

mean estimates of costs, the Agency 

calculated 90 percent confidence 

bounds by considering the uncertainty 

around the mean unit technology costs. 

Table VII–6 shows the undiscounted 

capital cost and all one-time costs 

broken out by rule component. A table 

comparing total annualized costs among 

the regulatory alternatives considered 

by the Agency is located in subsection 

VII.G. 

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2. Water system costs 

The proposed Stage 2 DBPR applies to 

all community or nontransient 

noncommunity water systems that add 

a chemical disinfectant other than UV or 

distribute water that has been treated 

with a disinfectant other than UV. EPA 

has estimated the cost impacts for both 

types of public water systems. As shown 

in Tables VII–5 a and b, the total 

annualized present value costs for CWSs 

is approximately $55.8 million and for 

NTNCWSs, $2.2 million, using a three 

percent discount rate ($60.8 million and 

$2.2 million using a seven percent 

discount rate). 

Although the number of systems 

adding treatment is small, treatment 

costs make up a significant portion of 

the total costs of the rule (more than 75 

percent of total rule costs). Table VII–7 

shows the baseline number of plants 

and the estimated percent of those 

plants adding treatment. The estimated 

percent of plants adding advanced 

treatment or converting to chloramines 

is 2.8 percent of all systems. A higher 

percentage of surface water plants are 

predicted to add treatment compared to 

ground water plants. However, the 

baseline number of ground water plants 

is larger than that of surface water 

plants, so there is a larger number of 

ground water plants adding treatment. 

Subsection VII.F. provides a more 

detailed explanation of treatment 

changes that may occur as a result of the 

proposed rule. 

All systems will incur costs for rule 

implementation. Some will need to 

conduct a one-time Initial Distribution 

System Evaluation (IDSE) and others (a 

different subgroup depending on the 

system size) may incur additional costs 

for routine DBP monitoring. Some 

systems may also have to conduct a 

peak excursion evaluation if single 

samples indicate high DBP levels. 

Sixty-nine percent of surface water 

and 7 percent of ground water CWSs are 

predicted to conduct the IDSE 

monitoring. EPA estimates that a very 

small portion of systems (approximately 

16 percent overall) will conduct 

additional routine monitoring beyond 

the Stage 1 DBPR requirements. 

However, fewer samples overall would 

be required if a population-based 

approach is implemented instead of the 

plant-based approach that is currently 

being used to estimate monitoring costs. 

Section V describes the populationbased approach in more detail and a 

discussion of how this approach may 

influence costs is provided in Appendix 

H of the EA (USEPA 2003i). A small 

percentage of systems (approximately 

3.0 percent of surface water CWSs and 

0 percent of ground water systems) are 

expected to experience significant 

excursions. 

A complete discussion of the rule 

provisions is located in section V of this 

preamble; the Stage 2 DBPR Economic 

Analysis includes a complete analysis of 

rule impacts (USEPA 2003i). Table VII–

8 summarizes the number of systems 

subject to non-treatment related rule 

activities. Column D indicates the 

number of systems expected to use the 

standard monitoring program to 

implement the IDSE. Column F 

indicates the number of systems 

expected to increase monitoring sites 

beyond that required by Stage 1. The 

last two columns show the number and 

percent of plants estimated to 

experience significant excursions each 

year.

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In addition to using distributions to 

develop unit cost estimates, the Agency 

conducted sensitivity analyses to further 

explore uncertainty regarding system 

compliance estimates. The first two 

sensitivity analyses were prepared to 

evaluate the possibility that the IDSE 

monitoring requirement will result in 

more systems needing to install 

treatment beyond what is predicted in 

the current cost model (see chapter 7 of 

the EA, USEPA 2003i, for details of this 

analysis). Table VII–9 lists the high-end 

estimates of the number of systems 

adding treatment in IDSE sensitivity 

analyses No. 1 and No. 2. For both IDSE 

sensitivity analyses, only small 

additional impacts were assumed 

possible for systems serving 10,000 

people or fewer because such systems 

generally have much less complicated 

distribution systems than larger 

systems. EPA estimated that the mean 

annualized costs at the 3% discount rate 

could be as high as $77.5 million (IDSE 

Sensitivity Analysis No. 1) or $108.8 

million (IDSE Sensitivity Analysis No. 

2) versus the Preferred Alternative 

analysis estimate of $57.4 million. At 

the 7% discount rate these estimates 

would respectively correspond to $86.1 

million, $120.7 million, and $63.3 

million.

EPA believes that the percentage of 

systems estimated to add treatment 

under IDSE sensitivity analyses No. 1 

and No. 2 are overestimates and that the 

estimate for the Preferred Alternative is 

likely to already capture the influence of 

the IDSE because of the conservative 

assumptions used in the analysis. For 

example, the compliance forecast 

analysis assumes that systems will try to 

meet the LRAA MCLs with a 20% 

margin of safety. Systems complying by 

switching to chloramines may choose to 

meet the new MCLs with a much 

smaller margin of safety since 

chloramines dampen the variability of 

DBP concentrations within the 

distribution system. Furthermore, EPA 

believes that the number of ground 

water and small surface water systems 

adding chloramines or changing 

technology in the baseline analysis may 

be overestimated because their 

monitoring requirements are expected to 

be very similar from Stage 1 to Stage 2. 

The Stage 1 DBPR required only one 

compliance monitoring location (at the 

point of maximum residence time) for 

producing surface water systems serving 

between 500 and 10,000 people and for 

all ground water systems. The Stage 2 

DBPR requires that these systems add an 

additional site if they determine that 

their high TTHM and high HAA5 

concentrations do not occur at the same 

location. If systems maintain a single 

monitoring location for the Stage 2 

DBPR, as many are expected to do, 

calculation of compliance will produce 

the same results for the running annual 

average (RAA) and locational running 

annual average (LRAA) measure, 

implying that they are not likely to add 

treatment for the Stage 2 DBPR if they 

comply with the Stage 1 DBPR. 

EPA conducted a third sensitivity 

analysis to evaluate the possibility that 

small systems will continue to monitor 

at one point in their distribution system. 

In this sensitivity analysis, EPA 

assumed that no surface water plants 

serving fewer than 10,000 people and no 

ground water plants would add 

treatment to meet Stage 2 DBPR 

requirements (i.e., only costs are 

associated for large surface water 

systems). Under this analysis, the 

average cost figures are reduced 

dramatically from $57.4 million or $63.3 

million to $22.9 million or $25.7 million 

using a 3 percent or 7 percent discount 

rate, respectively, for the Preferred 

Regulatory Alternative. Chapter 7 of the 

Economic Analysis (USEPA 2003i) 

contains a detailed explanation of the 

aforementioned sensitivity analysis. 

3. State Costs 

The Agency estimates that the States 

and primacy agencies will incur an 

annualized present value cost of $1.1 

million to $1.5 million (using a three 

percent and seven percent discount rate, 

respectively). In order to estimate the 

cost impact to States, EPA considered 

initial implementation costs, costs for 

assisting systems in evaluating IDSE 

information, and for annual rule 

implementation activities. EPA 

considered the incremental change in 

activities that result from the Stage 2 

DBPR. For example, States may have to 

update their databases to track the new 

Stage 2 DBPR monitoring strategy but 

could modify the system they developed 

for the Stage 1 DBPR. EPA accounted for 

the cost of a Stage 1 DBPR database in 

the Stage 1 Regulatory Impact Analysis 

(USEPA 1998f). State costs are not 

expected to change dramatically 

between alternatives. 

4. Non-quantifiable 

EPA has identified and quantified 

costs that it believes are likely to be 

significant. In some instances, EPA did 

not include a potential cost element 

because it believes the effects are 

relatively minor and difficult to 

estimate. For example, the Stage 2 DBPR 

may be the determining factor in the 

decision by some small water systems to 

merge with neighboring systems. Such 

changes have both costs (legal fees and 

connecting infrastructure) and benefits 

(economies of scale). Likewise, costs for 

procuring a new source of water would 

have costs for new infrastructure but 

could result in lower treatment costs. 

Also, EPA was unable to quantify 

several distribution system-related


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changes that can reduce TTHM and 

HAA5 levels. Activities such as looping 

distribution systems and optimizing 

storage can minimize retention times 

and help to control DBP formation. 

Costs for these activities range from 

almost zero (modifying retention time) 

to more substantial costs for modifying 

distribution systems. In the absence of 

detailed information needed to make 

cost evaluations for situations such as 

these, EPA has included a discussion of 

possible effects where appropriate. 

E. Expected System Treatment Changes 

In order to quantify the effects of the 

Stage 2 DBPR, it is necessary to predict 

how plants will modify their treatment 

processes to meet the proposed 

requirements. To estimate the 

incremental impacts of the Stage 2 

DBPR, relative to the Stage 1 DBPR, EPA 

compared predicted ‘‘ending 

technologies’’ (types of treatment in use 

after implementation of the Stage 2 

DBPR) to the distribution of baseline 

technologies predicted to be in place 

after the implementation of the Stage 1 

DBPR. This subsection outlines the 

process for deriving baseline and ending 

Stage 2 technology distributions that are 

the basis for the national cost estimates 

of today’s proposed rule. 

1. Pre-Stage 2 DBPR Baseline Conditions 

Development of the Pre-Stage 2 

baseline (i.e., conditions following the 

Stage 1 DBPR) consists of the following 

processes: 

• Compiling an industry profile—

identifying and collecting information 

on the segment(s) of the water supply 

industry subject to the Stage 2 DBPR; 

• Characterizing influent water 

quality—summarizing the relevant 

characteristics of the raw water treated 

by the industry; and 

• Characterizing treatment for the 

Stage 1 DBPR—predicting what the 

industry will do to comply with the 

provisions of the Stage 1 DBPR.

Section IV of this document details 

the data sources EPA used to 

characterize water quality and treatment 

practices for the nation’s public water 

systems. EPA also used information in 

the Water Industry Baseline Handbook

(USEPA 2000j) to develop the industry 

profile. The Baseline Handbook uses 

data derived from the 1995 Community 

Water Systems Survey and the Safe 

Drinking Water Information System to 

characterize the U.S. drinking water 

systems. Another EPA study, 

Geometries and Characteristics of Water 

Systems Report (USEPA 2000k), also 

provided information for the industry 

profile. 

EPA developed and used a model 

(SWAT) to characterize treatment 

following the Stage 1 DBPR and Stage 2 

DBPR options considered. SWAT served 

as the primary tool to predict changes in 

treatment and DBP occurrence. The 

model used a series of algorithms and 

decision rules to predict the type of 

treatment a large surface water plant 

will use given a specific regulatory 

alternative and source water quality. 

Other tools were used to estimate 

practices at large ground water systems 

or any medium or small systems. A 

Delphi process (a detailed technical 

treatment characterization and DBP 

occurrence review by drinking water 

experts) was used to predict treatment 

changes for large ground water systems 

(those serving 10,000 or more people). 

The results of the SWAT analyses and 

the Delphi process were extrapolated to 

the medium surface water and ground 

water systems based on analysis of 

source water treatment characteristics 

and treatment decision trees. For the 

small surface and ground water systems 

analyses, a group of experts provided 

predictions for a pre-Stage 2 baseline 

and resulting treatment and water 

quality conditions under the Stage 2 

DBPR regulatory alternatives. A detailed 

description of these analyses can be 

found in the Economic Analysis for the 

Stage 2 DBPR (USEPA 2003i). 

2. Predicted Technology Distributions 

Post-Stage 2 DBPR 

The treatment compliance forecast for 

the Stage 2 DBPR has two components—

1) the percent of plants that must add 

treatment to comply with Stage 2 DBPR 

requirements, and 2) the treatment 

technologies these plants are predicted 

to select. This information, coupled 

with the baseline data discussed before, 

provides an estimate of the total number 

of plants using specific technologies to 

meet the requirements of the proposed 

Stage 2 DBPR. National costs are then 

generated using technology unit cost 

information. 

The four step process EPA used to 

develop a Stage 2 DBPR compliance 

forecast is summarized in table VII–10. 

The difference between the Stage 1 

DBPR Technology Selections and Stage 

2 DBPR Technology Selections (Step 4—

Incremental Technology Selections) was 

used to develop national cost estimates 

for today’s proposed rule. Tables VII–11 

a and b (surface water) and VII–12 a and 

b (ground water) show the incremental 

technology selections shown as the 

percent change between Stage 1 and 

Stage 2 DBP rules.

TABLE VII–10.—STAGE 2 DBPR 

COMPLIANCE FORECAST SUMMARY

Step Description of Step 

1 ........ Model a pre-Stage 1 baseline scenario using Information Collection 

Rule data to allow consistent comparison between different rule alternatives. 

2 ........ Model technology selection to meet 

Stage 1 DBPR requirements 

(Stage 1 DBPR Technology Selection). 

3 ........ Model technology selection to meet 

Stage 2 DBPR requirements 

(Stage 2 DBPR Technology Selection). 

4 ........ Subtract the results in Step 2 from 

Step 3 and adjust to obtain the incremental impact of an alternative 

(Stage 2 DBPR incremental technology selection). 

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F. Estimated Household Costs of the 

Proposed Rule 

This analysis considers the potential 

increase in a household’s water bill if a 

system passed the entire cost increase 

resulting from this rule on to their 

customers. It is a tool to gauge potential 

impacts and should not be construed as 

precise estimates of potential changes to 

individual water bills. 

Overall, the potential increase in 

mean annual water bill per household is 

estimated to be $8.38 for those systems 

that need to install technology to 

comply with this rule. Table VII–13 

shows the range of household costs for 

all surface and ground water systems 

subject to the rule and also only for 

those systems installing technology to 

comply with this rule. For all systems, 

including those that may not have to 

take any additional action to comply 

with this rule but are still subject to its 

provisions, the mean annual household 

cost is $0.51. The last two columns of 

Table VII–13 show the potential impact 

as the percent of households that will 

incur either less than a $1 or less than 

a $10 increase in their monthly water 

bills (shown in the table as annual 

values). For systems adding treatment, 

84% of households will face less than 

a $1 increase in their monthly bill, 

while 99% are expected to face less than 

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Both household cost estimates reflect 

costs for rule implementation (e.g., 

reading and understanding the rule), 

IDSE, additional routine monitoring, 

and treatment changes. Although 

implementation and the IDSE represent 

relatively small, one-time costs, they 

have been annualized and included in 

the analysis to provide a complete 

picture of household costs. 

Overall, EPA estimates that 99 percent 

of the 98 million households that are 

provided disinfected drinking water 

would face less than $1 increase in their 

monthly water bill. Approximately 86 

percent of the households impacted by 

the rule are served by systems serving 

at least 10,000 people; these systems 

experience the lowest increases in costs 

due to significant economies of scale. 

Households served by small systems 

that install advanced technologies will 

face the greatest increases in annual 

costs. The cumulative distributions of 

household costs for all systems are 

presented in the Economic Analysis 

(USEPA 2003i). 

When interpreting the results of the 

household cost analysis, it is important 

to remember that systems, especially 

small systems, may have other options 

that were not included in the 

compliance forecast. For example, the 

system may identify another water 

source that may form lower levels of 

TTHM and HAA5. Systems that can 

identify such an alternate water source 

may not have to treat that water as much 

as their current source, resulting in 

lower treatment costs that may offset the 

costs of obtaining water from the 

alternate source. Systems may also be 

able to connect to a neighboring water 

system. While connecting to another 

system may not be feasible for some 

remote systems, EPA estimates that 

more than 22 percent of all small water 

systems are located within metropolitan 

regions (USEPA 2000c) where distances 

between potential connecting water 

systems may not present a prohibitive 

barrier. Consolidation was not an 

element used in developing the 

compliance forecasts for small systems. 

Costs for consolidation may be either 

greater or less than the costs for 

changing technologies, and 

consolidation may have other benefits 

(e.g., lower costs for compliance with 

future regulations). In addition, 

potentially lower cost alternatives such 

as controlling water residence time in 

the distribution systems were not 

included in the compliance forecast.

Also, more small systems than 

projected in the primary analysis may 

already be in compliance with Stage 2 

DBPR. A sensitivity analysis discussed 

in the subsection VII.D.2 describes this 

issue in more detail. Also, certain 

technologies installed to treat DBPs may 

treat many other contaminants thus 

eliminating the need to install 

additional equipment to comply with 

future drinking water regulations. 

G. Incremental Costs and Benefits of the 

Proposed Stage 2 DBPR 

Incremental costs and benefits are 

those that are incurred or realized in 

reducing DBP exposures from one 

alternative to the next more stringent 

alternative. Estimates of incremental 

costs and benefits are useful in 

considering the economic efficiency of 

different regulatory options considered 

by the Agency. However, as pointed out 

by the Environmental Economics 

Advisory Committee of the Science 

Advisory Board, efficiency is not the 

only appropriate criterion for social 

decision making (USEPA 2000n). 

Generally, the goal of an incremental 

analysis is to identify the regulatory 

option where net social benefits are 

maximized. If net incremental benefits


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are positive, society is incurring greater 

costs as a result of the health damages 

compared to the costs society could pay 

to reduce those health damages (i.e.

society would be better off to invest 

more in controlling the health damage). 

If net incremental benefits are negative, 

than the cost of the additional control is 

higher than the value of the additional 

health damages avoided. Therefore, the 

‘‘efficient’’ regulatory level is where the 

next additional incremental reduction 

in health damages equals the 

incremental cost of achieving that 

reduction. However, the usefulness of 

this analysis is constrained when major 

benefits and/or costs are unquantified or 

not monetized. 

For the proposed Stage 2 DBPR, 

presentation of incremental quantitative 

benefit and cost comparisons may be 

unrepresentative of the true net benefits 

of the rule because a significant portion 

of the rule’s potential benefits are nonquantifiable (see section C.1). Tables 

VII–14 and VII–15 show the total 

estimated costs and benefits for each 

alternative. Evaluation of the 

incremental changes between different 

rows in the tables shows that 

incremental costs generally fall within 

the range of incremental benefits for 

each more stringent alternative. Equally 

important, the addition of any benefits 

attributable to the non-quantified 

categories would add to the benefits 

without any increase in costs.

TABLE VII–14.—TOTAL ANNUALIZED PRESENT VALUE COSTS BY RULE ALTERNATIVE

($millions, 2000$) 

Rule alternative 

Total annualized cost ($millions) 

3 Percent discount rate 7 Percent discount rate 

Mean estimate 

90 Percent confidence bound 

Mean estimate 

90 Percent confidence bound 

Lower (5th % 

tile) 

Upper (95th % 

tile) 

Lower (5th % 

tile) 

Upper (95th % 

tile) 

Preferred .................................................. $59.1 $54.3 $63.9 $64.6 $59.2 $70.0 

Alt. 1 ......................................................... 182.2 165.1 199.6 195.1 175.9 214.3 

Alt. 2 ......................................................... 409.6 383.6 435.7 442.7 413.4 472.2 

Alt. 3 ......................................................... 594.3 556.3 631.9 644.2 601.1 686.9 

Note: Costs represent values in millions of 2000 dollars. Estimates are discounted to 2003—90 percent Confidence Intervals reflect uncertainty 

in technology unit cost estimates 

Source: Economic Analysis (USEPA 2003i) exhibit 6.24 

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The range of quantified benefits 

increases significantly with Alternatives 

2 and 3. However, the associated costs 

also increase significantly—cost figures 

presented in Table VII–14 show values 

approaching or exceeding $500 million


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per year. Although the estimated 

benefits for Alternatives 2 and 3 are 

potentially significant, EPA rejected 

these alternatives because the Agency 

believes that the uncertainty about the 

health effects data does not warrant the 

additional expense associated with 

these regulatory alternatives. 

Given the uncertainty in the health 

effects, and the resulting rejection of 

Alternatives 2 and 3, a comparison of 

Alternative 1 with the Preferred 

Alternative shows that Alternative 1 

would have approximately the same 

benefits as the Preferred Alternative but 

with greater costs. This results from the 

inability of the Agency to estimate the 

additional benefits of reducing the 

bromate MCL. Alternative 1 was also 

determined to be unacceptable due to 

the potential for increased risk of 

microbial exposure. See section VII.A of 

today’s action for a description of 

regulatory alternatives. 

H. Benefits From the Reduction of CoOccurring Contaminants 

Installing certain technologies to 

control DBPs also has the added benefit 

of controlling other drinking water 

contaminants. For example, some 

membrane technologies (depending on 

pore size) installed to reduce DBP 

precursors can also reduce or eliminate 

many other drinking water 

contaminants, including arsenic and 

microbial pathogens. EPA has finalized 

a rule to further control arsenic level in 

drinking water and has proposed the 

Ground Water Rule to address microbial 

contamination. The Stage 2 DBPR is also 

being concurrently proposed with the 

Long Term 2 Enhanced Surface Water 

Treatment Rule. Because of the 

difficulties in establishing which 

systems would have multiple problems 

such as microbial contamination, 

arsenic, and DBPs (or any combination 

of the three), no estimate was made of 

the potential cost savings from 

addressing more than one contaminant 

simultaneously. 

I. Are There Increased Risks From Other 

Contaminants? 

Today’s proposed rule may slightly 

shift the distribution of TTHM and 

HAAs to brominated species. Some 

systems, depending on bromide and 

organic precursor levels in the source 

water and technology selection, may 

experience a shift to higher ratios or 

concentrations of brominated DBPs 

while the overall TTHM or HAA5 

concentration decreases. However, EPA 

anticipates that this phenomenon may 

only occur in a small percentage of 

systems affected. For most systems, 

overall levels of DBPs, as well as 

brominated DBP species, should 

decrease as a result of this rule. 

EPA’s analysis shows that a large 

portion of systems that do not currently 

meet Stage 2 requirements will do so by 

switching from chlorination to 

chloramination; approximately 5% of 

surface water plants and 1.3% of ground 

water plants in systems serving greater 

than 10,000 are estimated to convert to 

chloramination in order to comply with 

the Stage 2 DBPR from the Stage 1 DBPR 

(USEPA 2003i). A potential 

chloramination byproduct is Nnitrosodimethylamine (NDMA), a 

probable human carcinogen. The 

concern over the formation of NDMA in 

the treatment process is based on the 

compound’s ability to persist for a long 

period of time in the distribution 

system. The mechanism of formation of 

NDMA, however, is still under 

examination. A number of ongoing 

studies will also evaluate occurrence, 

factors that affect NDMA formation, 

mechanisms, treatment effectiveness 

and improved analytical methods for 

measuring NDMA. 

Another contaminant of concern to 

the Agency is chlorite. Levels may 

increase slightly because of technology 

shifts to chlorine dioxide resulting from 

this rule but very few systems (<0.1 

percent) are predicted to install this 

technology. However, individual 

systems will not shift to chlorine 

dioxide unless they can meet the 

chlorite MCL (established under the 

Stage 1 DBPR) which is considered 

protective of public health.

EPA also considered the impact this 

rule may have on microbial 

contamination that may result from 

altering disinfection practices. To 

address this concern, the Agency 

developed this rule jointly with the 

Long Term 2 Enhanced Surface Water 

Treatment Rule (LT2ESWTR). EPA 

expects that the LT2ESWTR provisions 

will prevent significant increases in 

microbial risk resulting from the Stage 

2 DBPR. EPA also expects the Ground 

Water Rule, scheduled for promulgation 

in 2003, to prevent any increases in 

microbial risk in ground water systems 

deemed vulnerable to source water 

contamination. 

J. Effects on General Population and 

Subpopulation Groups 

Section III of today’s proposed rule 

discusses the health effects associated 

with DBPs on the general population as 

well as the effects on pregnant women 

and fetuses. In addition, health effects 

associated with children and pregnant 

women are discussed in greater detail in 

subsection VIII.G of this preamble. 

K. Uncertainties in Baseline, Risk, 

Benefit, and Cost Estimates 

Today’s proposal models the current 

baseline risk from DBP exposure as well 

as the reduction in risk and the cost for 

various rule options. There is 

uncertainty regarding many aspects of 

this analysis including the risk 

calculation, the benefit estimate, and the 

cost estimates. EPA has tried to capture 

much of the uncertainty and also the 

variability associated with many of the 

inputs used in the economic analysis by 

using distributions or ranges as model 

inputs instead of point estimates 

whenever possible. The Stage 2 DBPR 

EA contains a more extensive 

discussion of the modeling techniques 

used to address uncertainty and 

variability (USEPA 2003i). 

In addition, the Agency conducted 

sensitivity analyses to address 

uncertainty. The sensitivity analyses 

focus on various benefit and cost factors 

that may have a significant influence on 

the outcome of the rule. All of these 

sensitivity analyses are explained in 

more detail in the EA for the Stage 2 

DBPR (USEPA 2003i). 

The major source of benefit 

uncertainty is the scientific uncertainty 

regarding the impact of DBP exposure 

on reproductive and developmental 

outcomes. However, the Agency 

believes that the monetized value of 

these outcomes could be significant. As 

discussed in subsection VII.C.1, EPA 

performed an illustrative calculation 

that explored the potential implications 

for the proposed rule using some of the 

published results on fetal loss, but did 

not attempt to quantify benefits 

associated with reducing other 

reproductive and developmental 

endpoints potentially associated with 

DBP exposure. 

Another possible underestimation of 

today’s monetized benefits results from 

the inability of the Agency to quantify 

or monetize the potential benefit from 

avoiding other cancers associated with 

DBP exposure such as colon and rectal 

cancers. Furthermore, while the Agency 

estimated the range of bladder cancer 

risks avoided to be 0 to 182 cases per 

year, the true risk of bladder cancer 

avoided from decreased DBP exposure 

may be higher than this range. 

While EPA believes it has accounted 

for the significant costs of today’s 

proposed rule, there are uncertainties 

about some of the cost inputs. As 

discussed in subsection VII.D.4, cost 

estimates do not include some 

alternatives to installing treatment (e.g., 

improving management of distribution 

system residence time) that may be a 

less costly means of complying with the

49648 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

Stage 2 DBPR. The Agency also 

explored two additional uncertainties 

which might have the greatest impact on 

our current estimates by conducting 

sensitivity analyses. These include the 

impact of IDSE monitoring and the 

possibility that the primary analysis 

overestimates the compliance forecast 

for small surface water systems and all 

ground water systems. A detailed 

discussion of these analyses can be 

found in chapter 7 of the Economic 

Analysis (USEPA 2003i). 

Last, EPA has recently proposed or 

finalized new regulations for arsenic, 

radon, and microbials in ground water 

systems (Ground Water Rule); 

Cryptosporidium in small surface water 

systems and filter backwash in all 

system sizes (LT1ESWTR and Filter 

Backwash Rule); as well as concurrently 

proposing additional microbial control 

in surface water systems (Long Term 2 

Enhanced Surface Water Treatment 

Rule). These rules may have 

overlapping impacts on some drinking 

water systems but it is not possible to 

estimate these because of lack of 

information on co-occurrence. However, 

it is possible for a system to choose 

treatment technologies that would 

address multiple contaminants. 

Therefore, the total cost impact of these 

drinking water rules is uncertain; 

however, it may be less than the 

estimated total cost of all individual 

rules combined. 

L. Benefit/Cost Determination for the 

Proposed Stage 2 DBPR 

The Agency has determined that the 

quantified and unquantified benefits of 

the proposed Stage 2 DBPR justify the 

costs. As discussed previously, the main 

concern for the Agency and the 

Advisory Committee involved in the 

Stage 2 rulemaking process was to 

address potential reproductive and 

developmental impacts associated with 

exposure to high DBP levels. The 

proposed rule achieves this objective 

using the least cost alternative by 

modifying how the annual average DBP 

level is calculated. This will reduce 

both average DBP levels associated with 

bladder cancer (and possibly other 

cancers) and peak DBP levels which are 

potentially associated with reproductive 

and developmental effects. In addition, 

this rule may reduce uncertainty about 

drinking water quality and may allow 

some systems to avoid installing 

additional technology to meet future 

drinking water regulations. 

Compared to other rule options 

consider by the Agency, the proposed 

rule option is also the most costeffective. The cost-effectiveness analysis 

compares the annual dollar cost of the 

rule to the annual number of bladder 

cancer cases potentially avoided. For 

bladder cancer reduction, the cost per 

case avoided for the proposed rule 

would be $0.3 million if the PAR is 

17%, and $3.1 million if the PAR is 2%, 

and also varies depending on the 

discount rate used. 

M. Request for Comment 

The Agency requests comment on all 

aspects of the rule’s economic impact 

analysis. Specifically, EPA seeks input 

into the following issues: (1) To what 

extent can systems install treatment to 

address multiple contaminants?; (2) Are 

there methods for monetizing potential 

reproductive and developmental 

endpoints associated with DBP 

exposure?; (3) To what extent will use 

of chloramination increase levels of 

NDMA and potentially associated health 

risks, and how should this be 

considered in this rule making; and (4) 

How should the Agency value nonfatal 

cancers? Specifically, EPA uses a range 

of severities to calculate the WTP 

estimate to avoid a case of chronic 

bronchitis. Should the Agency only 

consider the most severe case of chronic 

bronchitis as a better proxy for a nonfatal cancer? Also, should the Agency 

use the risk-risk trade-off estimate of 

WTP to avoid a case of chronic 

bronchitis instead of the risk-dollar 

trade-off estimate (see the EA (USEPA 

2003i) for a complete discussion of 

these issues)? 

VIII. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

Under Executive Order 12866, (58 FR 

51735, October 4, 1993) the Agency 

must determine whether the regulatory 

action is ‘‘significant’’ and therefore 

subject to OMB review and the 

requirements of the Executive Order. 

The Order defines ‘‘significant 

regulatory action’’ as one that is likely 

to result in a rule that may: 

(1) Have an annual effect on the 

economy of $100 million or more or 

adversely affect in a material way the 

economy, a sector of the economy, 

productivity, competition, jobs, the 

environment, public health or safety, or 

State, local, or Tribal governments or 

communities;

(2) Create a serious inconsistency or 

otherwise interfere with an action taken 

or planned by another agency; 

(3) Materially alter the budgetary 

impact of entitlements, grants, user fees, 

or loan programs or the rights and 

obligations of recipients thereof; or 

(4) Raise novel legal or policy issues 

arising out of legal mandates, the 

President’s priorities, or the principles 

set forth in the Executive Order. 

Pursuant to the terms of Executive 

Order 12866, it has been determined 

that this rule is a ‘‘significant regulatory 

action.’’ As such, this action was 

submitted to OMB for review. Changes 

made in response to OMB suggestions or 

recommendations will be documented 

in the public record. 

B. Paperwork Reduction Act 

The information collection 

requirements in this proposed rule have 

been submitted for approval to the 

Office of Management and Budget 

(OMB) under the Paperwork Reduction 

Act, 44 U.S.C. 3501 et seq. The 

Information Collection Request (ICR) 

document prepared by EPA has been 

assigned ICR No. 2068.01 (USEPA 

2003m). 

The information collected as a result 

of this rule will allow the States and 

EPA to determine appropriate 

requirements for specific systems, and 

to evaluate compliance with the rule. 

For the first 3 years after Stage 2 DBPR 

promulgation, the major information 

requirements involve monitoring 

activities, which include conducting the 

IDSE and submission of the IDSE report, 

and tracking compliance. The 

information collection requirements are 

mandatory (Part 141), and the 

information collected is not 

confidential. 

The estimate of annual average 

burden hours for the Stage 2 DBPR for 

systems and States is 248,568 hours. 

This estimate covers the first three years 

of the Stage 2 DBPR and includes 

implementation of Stage 2A and most of 

the IDSE (small system reports are not 

due until the fourth year). The annual 

average aggregate cost estimate is $18.0 

million for operation and maintenance 

as a purchase of service for lab work, 

and $6.8 million is associated with 

labor. The annual burden hour per 

response is 2.59 hours. The frequency of 

response (average responses per 

respondent) is 11.8 annually. The 

estimated number of likely respondents 

is 8,131 per year (the product of burden 

hours per response, frequency, and 

respondents does not total the annual 

average burden hours due to rounding). 

Because disinfecting systems have 

already purchased basic monitoring 

equipment to comply with the Stage 1 

DBPR, EPA assumes no capital start-up 

costs are associated with the Stage 2 

DBPR ICR. 

Burden means the total time, effort, or 

financial resources expended by persons 

to generate, maintain, retain, or disclose 

or provide information to or for a 

Federal agency. This includes the time

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49649

needed to review instructions; develop, 

acquire, install, and utilize technology 

and systems for the purposes of 

collecting, validating, and verifying 

information, processing and 

maintaining information, and disclosing 

and providing information; adjust the 

existing ways to comply with any 

previously applicable instructions and 

requirements; train personnel to be able 

to respond to a collection of 

information; search data sources; 

complete and review the collection of 

information; and transmit or otherwise 

disclose the information. 

An Agency may not conduct or 

sponsor, and a person is not required to 

respond to a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for EPA’s regulations in 40 

CFR are listed in 40 CFR part 9. 

To comment on the Agency’s need for 

this information, the accuracy of the 

provided burden estimates, and any 

suggested methods for minimizing 

respondent burden, including the use of 

automated collection techniques, EPA 

has established a public docket for this 

rule, which includes this ICR, under 

Docket ID No. OW–2002–0043. Submit 

any comments related to the ICR for this 

proposed rule to EPA and OMB. See 

ADDRESSES section at the beginning of 

this notice for where to submit 

comments to EPA. Send comments to 

OMB at the Office of Information and 

Regulatory Affairs, Office of 

Management and Budget, 725 17th 

Street, NW., Washington, DC 20503, 

Attention: Desk Office for EPA. Since 

OMB is required to make a decision 

concerning the ICR between 30 and 60 

days after August 18, 2003, a comment 

to OMB is best assured of having its full 

effect if OMB receives it by September 

17, 2003. The final rule will respond to 

any OMB or public comments on the 

information collection requirements 

contained in this proposal. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Analysis 

(RFA), as amended by the Small 

Business Regulatory Enforcement 

Fairness Act (SBREFA) of 1996, 5 U.S.C. 

601 et seq., generally requires an agency 

to prepare a regulatory flexibility 

analysis of any rule subject to notice 

and comment rulemaking requirements 

under the Administrative Procedure Act 

or any other statute, unless the Agency 

certifies that the rule will not have a 

significant economic impact on a 

substantial number of small entities. 

Small entities include small businesses, 

small organizations, and small 

governmental jurisdictions. 

The RFA provides default definitions 

for each type of small entity. It also 

authorizes an agency to use alternative 

definitions for each category of small 

entity, ‘‘which are appropriate to the 

activities of the agency’’ after proposing 

the alternative definition(s) in the 

Federal Register and taking comment. 5 

U.S.C. 601(3) through (5). In addition to 

the above, to establish an alternative 

small business definition, agencies must 

consult with SBA’s Chief Counsel for 

Advocacy. 

For purposes of assessing the impacts 

of today’s proposed rule on small 

entities, EPA considered small entities 

to be public water systems serving 

10,000 or fewer persons. This is the cutoff level specified by Congress in the 

1996 Amendments to the Safe Drinking 

Water Act for small system flexibility 

provisions. In accordance with the RFA 

requirements, EPA proposed using this 

alternative definition in the Federal 

Register (63 FR 7620 (February 13, 

1998)), requested public comment, 

consulted with the Small Business 

Administration (SBA), and expressed its 

intention to use the alternative 

definition for all future drinking water 

regulations in the Consumer Confidence 

Reports regulation (63 FR 44511 (August 

19, 1998)). As stated in that final rule, 

the alternative definition is applied to 

this regulation. 

After considering the economic 

impacts of today’s proposed rule on 

small entities, I certify that this action 

will not have a significant economic 

impact on a substantial number of small 

entities. We have determined that 75 

small systems using surface water or 

ground water under the direct influence 

of surface water (GWUDI), which are 

1.67% of all such systems affected by 

the Stage 2 DBPR, will experience an 

impact of greater than or equal to 1% of 

their revenues, and 49 small systems 

using surface water or GWUDI, which 

are 1.09% of all such systems affected 

by the Stage 2 DBPR, will experience an 

impact of greater than or equal to 3% of 

their revenues; further, 109 small 

ground water systems, which are 0.28% 

of all such systems affected by the Stage 

2 DBPR, will experience an impact of 

greater than or equal to 1% of their 

revenues, and 38 small ground water 

systems, which are 0.10% of all such 

systems affected by the Stage 2 DBPR, 

will experience an impact of greater 

than or equal to 3% of their revenues 

(see Tables VIII–1 and VIII–2). 

BILLING CODE 6560–50–P

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BILLING CODE 6560–50–C

As a result of the input received from 

stakeholders, the EPA workgroup, the 

Advisory Committee, and other 

interested parties, EPA has developed 

MCLs using locational running annual 

averages (LRAA) of 0.080 and 0.060 mg/

L for TTHM and HAA5 respectively, in 

combination with Initial Distribution 

Systems Evaluations (IDSE), as the 

preferred Stage 2 DBPR option. LRAAs 

are running annual averages calculated 

for each sample location in the 

distribution system. Since many small 

systems only monitor at one location, 

they will effectively base their 

compliance with the Stage 1 DBPR on 

an LRAA and therefore will not be 

significantly affected by the Stage 2 

DBPR. In addition to meeting the MCLs 

for TTHM and HAA5, systems will be 

required to conduct IDSEs. The purpose 

of the IDSE is to identify compliance 

monitoring sites representing high 

TTHM and HAA5 levels in the 

distribution system. According to the 

Stage 2 DBPR Economic Analysis 

(USEPA 2003i), only 17% of all small 

water systems will conduct IDSE 

monitoring because small NTNCWSs are 

exempt from IDSE monitoring, systems 

serving fewer than 500 people may 

receive a waiver from their States, and 

other systems are eligible for a 40/30 

certification if all compliance 

monitoring samples have been ≤ 0.040 

and ≤ 0.030 mg/L for TTHM and HAA5 

respectively during the previous two 

years. A large number of small ground 

water systems will qualify for this 

certification. This provision is described 

in more detail in section V.H. of this 

preamble. 

Although not required by the RFA to 

convene a Small Business Advocacy


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49652 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

Review (SBAR) Panel because EPA 

determined that this proposal would not 

have a significant economic impact on 

a substantial number of small entities, 

EPA did convene a panel to obtain 

advice and recommendations from 

representatives of the small entities 

potentially subject to this rule’s 

requirements. 

Before convening the SBAR Panel, 

EPA consulted with a group of 24 SERs 

likely to be impacted by the Stage 2 M–

DBP Rules. The SERs included small 

system operators, local government 

officials, and small nonprofit 

organizations. The SERs were provided 

with background information on the 

Safe Drinking Water Act, Stage 1 DBPR, 

IESWTR, and Stage 2 DBPR alternatives 

and unit cost analyses resulting from 

using different technologies to meet the 

required MCLs in preparation for the 

teleconferences on January 28, 2000, 

February 25, 2000, and April 7, 2000. 

This information package included data 

on options and preliminary unit costs 

for treatment enhancements under 

consideration. It is important to note 

that, since EPA did not consider the 

IDSE requirements until after these 

consultations with SERs and the SBAR 

panel, no comments were received on 

the IDSE requirements from the SERs or 

the SBAR panel. However, small system 

representatives were included in the 

Advisory Committee that recommended 

the IDSE. 

During these conference calls, the 

information was discussed and EPA 

provided feedback and noted these 

initial SER comments. Following the 

calls, the SERs were asked to provide 

input on the potential impacts of the 

rule. Seven SERs provided written 

comments on these materials. These 

comments were provided to the SBAR 

Panel when the Panel convened in April 

25, 2000. After a teleconference between 

the SERs and the Panel on May 25, 

2000, the SERs were invited to provide 

additional comments on the information 

provided. Seven SERs provided 

additional comments on the rule 

components. 

In general, the SERs consulted on the 

Stage 2 M–DBP rules were concerned 

about the impact of these proposed rules 

on small water systems. They were 

particularly concerned with acquiring 

the technical and financial capability to 

implement requirements, maintaining 

flexibility to tailor requirements to their 

needs, and the limitations of small 

systems. 

The Small Business Advocacy Review 

(SBAR) Panel members for the Stage 2 

DBPR were: the Small Business 

Advocacy Chair of the Environmental 

Protection Agency, the Chief of the 

Standards and Risk Reduction Branch of 

the Office of Ground Water and 

Drinking Water within EPA’s Office of 

Water, the Administrator of the Office of 

Information and Regulatory Affairs 

within the Office of Management and 

Budget, and the Chief Counsel for 

Advocacy of the Small Business 

Administration. The Panel convened on 

April 25, 2000, and met five times 

before the end of the 60-day Panel 

period on June 23, 2000. The SBAR 

Panel’s report, ‘‘Final Report of the 

Small Business Advocacy Review Panel 

on Stage 2 Disinfectants and 

Disinfection Byproducts Rule (Stage 2 

DBPR) and Long-Term 2 Enhanced 

Surface Water Treatment Rule 

(LT2ESWTR)’’, the Small Entity 

Representatives (SERs) comments on 

components of the Stage 2 MDBP Rules, 

and the background information 

provided to the SBAR Panel and the 

SERs are available for review in the 

Office of Water Docket. 

Today’s proposal takes into 

consideration the recordkeeping and 

reporting concerns identified by the 

Panel and the SERs. The Panel 

recommended that EPA evaluate ways 

to minimize the rule recordkeeping and 

reporting burdens by ensuring that 

States have appropriate capacity for rule 

implementation and that EPA provide 

as much monitoring flexibility as 

possible to small systems. Continuity 

with the Stage 1 DBPR was maintained 

to the extent possible to ease the 

transition to the Stage 2 DBPR, 

especially for small systems. EPA’s 

decision to maintain the same MCLs for 

TTHM and HAA5 will also help to 

minimize the additional 

implementation burden. Generally, 

routine monitoring will be similar in 

frequency to monitoring for the Stage 1 

DBPR, and systems with low DBP levels 

will still be eligible for reduced 

monitoring. Many small systems will 

conduct the same amount of monitoring 

for the Stage 2 DBPR as for the Stage 1 

DBPR. Surface and ground water 

community water systems (CWSs) 

serving 500 to 9,999 people and ground 

water systems serving at least 10,000 

people may be required to add one 

sampling site and take an additional 

quarterly TTHM/HAA5 sample at that 

site. Also, EPA has specified 

consecutive system requirements; these 

will be new requirements in States 

where consecutive systems are not 

required to comply with some or all 

Stage 1 DBPR requirements. As noted 

before, since some small systems will be 

effectively complying with such 

requirements under the Stage 1 DBPR, 

the Stage 2 DBPR will not impose any 

additional burden on them. 

The Panel also noted the concern of 

several SERs that flexibility should be 

provided in the compliance schedule of 

the rule. SERs noted the technical and 

financial limitations that some small 

systems will have to address, the 

significant learning curve for operators 

with limited experience, and the need to 

continue providing uninterrupted 

service as reasons why additional 

compliance time may be needed for 

small systems. The panel encouraged 

EPA to keep these limitations in mind 

in developing the proposed rule and 

provide as much compliance flexibility 

to small systems as is allowable under 

the SDWA. EPA believes that the 

proposed compliance schedules 

provides sufficient time for small 

systems to achieve compliance. 

Under the proposed LT2ESWTR, 

certain subpart H systems with low 

levels of indicators such as E. coli will 

not have to monitor for 

Cryptosporidium. The efficacy of E. coli

as an indicator will be evaluated using 

the large system data. Thus, small 

systems E. coli monitoring cannot be 

initiated until large and medium system 

monitoring has been completed. The 

LT2ESWTR compliance time line for 

small systems thus lags 1.5 to 2.5 years 

behind the large and medium systems; 

timeline. Because the Stage 2 DBPR 

must be implemented on a simultaneous 

schedule, the compliance timeline is 

similarly delayed 1.5 to 2.5 years behind 

large and medium systems. In addition, 

if capital improvements are necessary 

for a particular PWS to comply, a State 

may allow the system up to an 

additional two years to comply with the 

MCL. The Agency is developing 

guidance manuals to assist small 

entities with their compliance efforts. 

The Panel considered a wide range of 

options and regulatory alternatives for 

providing small businesses with 

flexibility in complying with the Stage 

2 DBPR. The Panel recognized the 

concern shared by most stakeholders 

regarding the need to reduce DBP 

variability in the distribution system. 

This concern comes from recent studies 

that, while not conclusive, suggest that 

there may be adverse reproductive 

effects associated with relatively shortterm exposure to high levels of DBPs. 

Many small systems will be monitoring 

at only a single point in the distribution 

system (designed to represent the point 

of maximum TTHM and HAA5 

exposure), and many small systems will 

be monitoring only once during the 

year, at a time which corresponds to the 

season with the highest potential 

occurrence.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49653

Since there is a chance for this single 

sample to exceed an MCL, today’s 

proposal requires systems that exceed 

an MCL on an annual or less frequent 

sample to begin increased (quarterly) 

monitoring rather than immediately 

being in violation of the MCL. The 

system must comply with the MCL as an 

LRAA once it has collected four 

quarterly samples. This allows small 

systems to generally monitor less 

frequently (to reduce their monitoring 

burden) during the period when the 

highest DBP levels are expected (to 

protect public health) without 

penalizing them (by requiring them to 

meet an MCL that would effectively be 

based on a single highest value if the 

systems were immediately in violation 

after a single sample exceeds an MCL). 

This compliance determination is 

consistent with requirements for 

systems that monitor quarterly for 

whom compliance is based on the 

compliance monitoring results of the 

previous four quarters. 

It is important to note that based on 

the IDSE results, some small systems 

will have a high TTHM site that is 

different from the high HAA5 site. 

These systems will need to monitor at 

two sites under the Stage 2 DBPR. EPA 

believes that an approach based on 

compliance with 0.080 mg/L TTHM and 

0.060 mg/L HAA5 LRAAs is an effective 

way of addressing concerns regarding 

locational variability.

In addressing seasonal variability, the 

Panel was concerned about a regulatory 

alternative requiring compliance with 

0.080 mg/L TTHM and 0.060 mg/L 

HAA5 single highest value MCL 

(Alternative 2), because it would impose 

significant additional cost on some 

small systems. The Panel recommended 

that EPA instead explore an approach 

under which individual high values 

might trigger additional assessment and/

or notification requirements, rather than 

an MCL violation. 

EPA agrees with the panel 

recommendations on a single highest 

value MCL. Under today’s proposal, 

public water systems are required to 

maintain a record of TTHM and HAA5 

concentrations detected at each sample 

location. As part of the sanitary survey 

process, systems are required to conduct 

an evaluation and consult with their 

State regarding significant excursions in 

TTHM and HAA5 occurrence that have 

occurred. EPA is developing guidance 

for public water systems and States on 

how to identify significant excursions 

and conduct significant excursion 

evaluations, and how to reduce DBP 

levels through actions such as 

distribution system operational changes 

(USEPA 2003n) (Section V.E.). 

The Panel noted the strong concerns 

expressed by some SERs about the 

uncertainty in the current scientific 

evidence regarding health effects from 

exposure to DBPs, particularly regarding 

short term exposure. A Panel member 

recommended that EPA give further 

serious consideration to making a 

determination that the currently 

available scientific evidence does not 

warrant imposing additional regulatory 

requirements beyond those in the Stage 

1 DBPR at this time. This Panel member 

recommended that EPA instead 

continue to vigorously fund ongoing 

research in health effects, occurrence, 

and appropriate treatment techniques 

for DBPs, and reconsider whether 

additional requirements are appropriate 

during its next SDWA required six-year 

review of the standard. This panel 

member also recommended that EPA 

separately explore whether adequate 

data exist to warrant regulation of 

NTNCWSs at a national level at this 

time. 

EPA has considered these 

recommendations and believes the Stage 

2 DBPR is needed at this time to protect 

public health. EPA’s main mission is the 

protection of human health and the 

environment. When carrying out this 

mission, EPA must often make 

regulatory decisions with less than 

complete information and with 

uncertainties in the available 

information. EPA believes it is 

appropriate and prudent to err on the 

side of public health protection when 

there are indications that exposure to a 

contaminant may present risks to public 

health, rather than take no action until 

risks are unequivocally proven. 

Therefore, while recognizing the 

uncertainties in the available 

information, EPA believes that the 

weight of evidence represented by the 

available epidemiology and toxicology 

studies on chlorinated water and DBPs 

supports a hazard concern and a 

protective public health approach to 

regulation. In addition, EPA has an 

ongoing research program to study DBP 

health effects, occurrence, and 

treatment. 

EPA continues to be interested in the 

potential impacts of the proposed rule 

on small entities and welcome 

comments on issues related to such 

impacts. 

D. Unfunded Mandates Reform Act 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA), Public 

Law 104–4, establishes requirements for 

Federal agencies to assess the effects of 

their regulatory actions on State, local, 

and Tribal governments and the private 

sector. Under UMRA section 202, EPA 

generally must prepare a written 

statement, including a cost-benefit 

analysis, for proposed and final rules 

with ‘‘Federal mandates’’ that may 

result in expenditures by State, local, 

and Tribal governments, in the 

aggregate, or by the private sector, of 

$100 million or more in any one year. 

Before promulgating an EPA rule for 

which a written statement is needed, 

section 205 of the UMRA generally 

requires EPA to identify and consider a 

reasonable number of regulatory 

alternatives and adopt the least costly, 

most cost-effective or least burdensome 

alternative that achieves the objectives 

of the rule. The provisions of section 

205 do not apply when they are 

inconsistent with applicable law. 

Moreover, section 205 allows EPA to 

adopt an alternative other than the least 

costly, most cost-effective or least 

burdensome alternative if the 

Administrator publishes with the final 

rule an explanation why that alternative 

was not adopted. 

Before EPA establishes any regulatory 

requirements that may significantly or 

uniquely affect small governments, 

including Tribal governments, it must 

have developed, under section 203 of 

the UMRA, a small government agency 

plan. The plan must provide for 

notifying potentially affected small 

governments, enabling officials of 

affected small governments to have 

meaningful and timely input in the 

development of EPA regulatory 

proposals with significant Federal 

intergovernmental mandates and 

informing, educating, and advising 

small governments on compliance with 

the regulatory requirements. 

EPA has determined that this rule 

does not contain a Federal mandate that 

may result in expenditures of $100 

million or more for State, local and 

Tribal governments, in the aggregate, or 

the private sector in any one year. Based 

on total estimated nominal costs 

incurred by year, costs for public or 

private systems are not expected to 

exceed $100 million in any one year. In 

addition, total estimated annualized 

costs of this rule are $59 to $65 million 

for all systems, including labor burdens 

that States would face, such as training 

employees on the requirements of the 

Stage 2 DBPR, responding to PWS 

reports, and record keeping. Thus, 

today’s proposed rule is not subject to 

the requirements of sections 202 and 

205 of the UMRA. 

EPA has determined that the Stage 2 

DBPR contains no regulatory 

requirements that might significantly or 

uniquely affect small governments (see 

Tables VIII–1 and VIII–2). Since the 

Stage 2 DBPR affects all size systems

49654 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

and the impact on small entities will be 

0.00 to 0.11 percent of revenues, the 

Stage 2 DBPR is not subject to the 

requirements of section 203 of UMRA. 

Nevertheless, in developing this rule, 

EPA consulted with small governments 

(see sections VIII.B., VIII.C. and VIII.F.). 

In preparation for the proposed Stage 2 

DBPR, EPA conducted an analysis of 

small government impacts and included 

small government officials or their 

designated representatives in the 

rulemaking process. As noted 

previously, a variety of stakeholders, 

including small governments, had the 

opportunity for timely and meaningful 

participation in the regulatory 

development process through the 

SBREFA process, public stakeholder 

meetings, and Tribal meetings. 

Representatives of small governments 

took part in the SBREFA process for this 

rulemaking and they attended public 

stakeholder meetings. Through such 

participation and exchange, EPA 

notified several potentially affected 

small governments of requirements 

under consideration and provided 

officials of affected small governments 

with an opportunity to have meaningful 

and timely input into the development 

of this regulatory proposal. 

The Agency has developed fact sheets 

that describe requirements of the 

proposed Stage 2 DBPR. These fact 

sheets are available by calling the Safe 

Drinking Water Hotline at 800–426–

4791. 

E. Executive Order 13132: Federalism 

Executive Order 13132, entitled 

‘‘Federalism’’ (64 FR 43255, August 10, 

1999), requires EPA to develop an 

accountable process to ensure 

‘‘meaningful and timely input by State 

and local officials in the development of 

regulatory policies that have federalism 

implications.’’ ‘‘Policies that have 

federalism implications’’ is defined in 

the Executive Order to include 

regulations that have ‘‘substantial direct 

effects on the States, on the relationship 

between the national government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government.’’

This proposed rule will not have 

federalism implications. It will not 

impose substantial direct effects on the 

States, on the relationship between the 

national government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. The proposed 

rule has one-time costs for 

implementation of approximately $68.5 

million. Thus, Executive Order 13132 

does not apply to this rule.

Although Executive Order 13132 does 

not apply to this rule, EPA did consult 

with State and local officials in 

developing this proposed regulation. On 

February 20, 2001, EPA held a dialogue 

on both the Stage 2 DBPR and 

LT2ESWTR with representatives of 

State and local governmental 

organizations including those that 

represent elected officials. 

Representatives from the following 

organizations attended the consultation 

meeting: Association of State Drinking 

Water Administrators (ASDWA), the 

National Governors’ Association (NGA), 

the National Conference of State 

Legislatures (NCSL), the International 

City/County Management Association 

(ICMA), the National League of Cities 

(NLC), the County Executives of 

America, and health departments. At 

the consultation meeting, questions 

ranged from a basic inquiry into how 

Cryptosporidium gets into water to more 

detailed queries about anticipated 

implementation guidance, procedures, 

and schedules. No concerns were 

expressed. Some of the State and local 

organizations who attended the 

governmental dialogue on upcoming 

microbial and disinfection byproduct 

rulemakings were also participants in 

the Advisory Committee meetings and 

signed the Agreement in Principle. In 

addition, EPA consulted with a mayor 

in the SBREFA consultation described 

in section VIII B. 

In the spirit of Executive Order 13132, 

and consistent with EPA policy to 

promote communications between EPA 

and State and local governments, EPA 

specifically solicits comment on this 

proposed rule from State and local 

officials. 

F. Executive Order 13175: Consultation 

and Coordination With Indian Tribal 

Governments 

Executive Order 13175, entitled 

‘‘Consultation and Coordination with 

Indian Tribal Governments’’ (65 FR 

67249, November 9, 2000), requires EPA 

to develop ‘‘an accountable process to 

ensure meaningful and timely input by 

tribal officials in the development of 

regulatory policies that have tribal 

implications.’’ ‘‘Policies that have tribal 

implications’’ is defined in the 

Executive Order to include regulations 

that have ‘‘substantial direct effects on 

one or more Indian tribes, on the 

relationship between the Federal 

government and the Indian tribes, or on 

the distribution of power and 

responsibilities between the Federal 

government and Indian tribes.’’

Under Executive Order 13175, EPA 

may not issue a regulation that has 

Tribal implications, that imposes 

substantial direct compliance costs, and 

that is not required by statute, unless 

the Federal government provides the 

funds necessary to pay the direct 

compliance costs incurred by Tribal 

governments, or EPA consults with 

Tribal officials early in the process of 

developing the proposed regulation and 

develops a Tribal summary impact 

statement. 

EPA has concluded that this proposed 

rule may have Tribal implications 

because it may impose substantial direct 

compliance costs on Tribal 

governments, and the Federal 

government will not provide the funds 

necessary to pay those costs. 

Total Tribal costs are estimated to be 

approximately $199,372 per year (at a 3 

percent discount rate) and this cost is 

distributed across 559 Tribal systems. 

The cost for individual systems depend 

on system size and source water type. 

Of the 559 Tribes that may be affected 

in some form by the Stage 2 DBPR, 502 

use ground water as a source and 57 

systems use surface water or GWUDI. 

Since the majority of Tribal systems are 

ground water systems serving fewer 

than 500 people, less than 10 percent of 

all Tribal systems will likely have to 

conduct an IDSE. As a result, the Stage 

2 DBPR is most likely to have an impact 

on Tribes using surface water or GWUDI 

serving more than 500 people. 

Accordingly, EPA provides the 

following Tribal summary impact 

statement as required by section 5(b) of 

Executive Order 13175. EPA provides 

further detail on Tribal impact in the 

Economic Analysis for the Stage 2 

Disinfectants and Disinfection 

Byproduct Rule (USEPA 2003i). 

EPA consulted with Tribal officials 

early in the process of developing this 

regulation to permit them to have 

meaningful and timely input into its 

development. Consistent with Executive 

Order 13175, EPA engaged in outreach 

and consultation efforts with Tribal 

officials in the development of this 

proposed regulation. The most longterm participation of Tribes was on the 

Advisory Committee through a 

representative of the All Indian Pueblo 

Council (AIPC), which is associated 

with approximately 20 Tribes. 

In addition to obtaining Tribal input 

during the Advisory Committee 

negotiations, EPA presented the Stage 2 

DBPR at the 16th Annual Consumer 

Conference of the National Indian 

Health Board, the Environmental 

Council’s Annual Conference, and the 

EPA/Inter-Tribal Council of Arizona, 

Inc. Over 900 attendees representing 

Tribes from across the country attended 

the National Indian Health Board’s 

Consumer Conference and over 100

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49655

Tribes were represented at the annual 

conference of the National Tribal 

Environmental Council. Representatives 

from 15 Tribes participated at the EPA/

Inter-Tribal Council of Arizona meeting. 

At the first two conferences, an EPA 

representative conducted workshops on 

EPA’s drinking water program and 

upcoming regulations, including the 

Stage 2 DBPR. EPA sent the presentation 

materials and a meeting summary to 

over 500 Tribes and Tribal 

organizations. 

Fact sheets describing the 

requirements of the proposed rule and 

requesting Tribal input were distributed 

at an annual EPA Tribal meeting in San 

Francisco, and at a Native American 

Water Works Association meeting in 

Scottsdale, Arizona. EPA also worked 

through its Regional Indian 

Coordinators and the National Tribal 

Operations Committee to raise 

awareness of the development of the 

proposed rule. EPA mailed fact sheets 

on the Stage 2 DBPR to all of the 

federally recognized Tribes in 

November 2000, as well as the Tribal 

Caucus of the National Tribal 

Operations Committee. 

A few Tribes responded by requesting 

more information and expressing 

concern about having to implement too 

many regulations. Some members of the 

Tribal Caucus noted that the rule would 

have a benefit. They also expressed a 

concern about infrastructure costs and 

the lack of funding attached to the rule. 

In response to one Tribal 

representative’s comments on the 

November 2000 mailout, EPA explained 

the health protection benefit expected to 

be gained by this proposed rule. EPA 

also directed those who asked for more 

information to the Agreement in 

Principle on the EPA Web site. 

EPA also held a teleconference for 

Tribal representatives on January 24, 

2002. Prior to the teleconference, 

invitations were sent to all of the 

Federally-recognized Tribes, along with 

fact sheets explaining the rule. Twelve 

Tribal representatives and four regional 

Tribal Program Coordinators attended. 

The Tribal representatives requested 

further explanation of the rule and 

expressed concerns about funding 

sources. EPA also received calls from 

Tribes after the teleconference which 

provided EPA with further feedback. In 

the spirit of Executive Order 13175, and 

consistent with EPA policy to promote 

consultation between EPA and Tribal 

governments, EPA specifically solicits 

additional comment on this proposed 

rule from Tribal officials. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

and Safety Risks 

Executive Order 13045: ‘‘Protection of 

Children From Environmental Health 

Risks and Safety Risks’’ (62 FR 19885, 

April 23, 1997) applies to any rule that: 

(1) Is determined to be ‘‘economically 

significant’’ as defined under Executive 

Order 12866, and; (2) concerns an 

environmental health or safety risk that 

EPA has reason to believe may have a 

disproportionate effect on children. If 

the regulatory action meets both criteria, 

the Agency must evaluate the 

environmental health or safety effects of 

the planned rule on children, and 

explain why the planned regulation is 

preferable to other potentially effective 

and reasonably feasible alternatives 

considered by the Agency.

While this proposed rule is not 

subject to the Executive Order because 

it is not economically significant as 

defined in Executive Order 12866, EPA 

nonetheless has reason to believe that 

the environmental health or safety risk 

(i.e., the risk associated with DBPs) 

addressed by this action may have a 

disproportionate effect on children. As 

a matter of EPA policy, we have 

therefore assessed the environmental 

health or safety effect of DBPs on 

children. EPA has consistently and 

explicitly considered risks to infants 

and children in all assessments 

developed for this rulemaking. The 

results of the assessments are contained 

in section III of this preamble, Health 

Risks to Fetuses, Infants, and Children: 

A Review (USEPA 2003a), and in the 

Economic Analysis (USEPA 2003i). A 

copy of all documents has been placed 

in the public docket for this action. 

EPA’s Office of Water has historically 

considered risks to sensitive 

subpopulations (including fetuses, 

infants, and children) in establishing 

drinking water assessments, health 

advisories or other guidance, and 

standards (USEPA 1989c and USEPA 

1991a). Waterborne disease from 

pathogens in drinking water is a major 

concern for children and other 

subgroups (elderly, immune 

compromised, pregnant women) 

because of their increased 

vulnerabilities (Gerba et al. 1996). There 

is a concern for potential reproductive 

and developmental risks posed by DBPs 

to children and pregnant women 

(USEPA 1994b; USEPA 1998c, Reif et al.

2000; Tyl, 2000). Specific to this action, 

human epidemiology and animal 

toxicology studies on DBPs have shown 

potential increased risks for 

spontaneous abortion, still birth, neural 

tube defects, cardiovascular effects and 

low birth weight. This rule is designed 

to lower those risks. EPA has provided 

an illustrative calculation of potential 

fetal losses avoided in section VII.C.1. 

Section V.D of this preamble presents 

the regulatory alternatives that EPA 

evaluated for the proposed Stage 2 

DBPR, and the Economic Analysis 

(USEPA 2003i) provides a more detailed 

discussion. The Agency considered four 

alternatives involving different MCLs 

and different compliance calculations. 

The proposed alternative was 

recommended by the Advisory 

Committee and selected by EPA as the 

Preferred Regulatory Alternative 

because it provides significant public 

health benefits for an acceptable cost. 

EPA’s analysis of benefits and costs 

indicates that the proposed alternative 

is superior among those evaluated with 

respect to maximizing net benefits, as 

shown in the Economic Analysis 

(USEPA 2003i). The result of the Stage 

2 DBPR may include a reduction in 

reproductive and developmental risk to 

children and pregnant women and a 

reduction in cancer risk. 

It should also be noted that the 

LT2ESWTR, which will be implemented 

at the same time as this proposed rule, 

provides better controls of pathogens 

and achieves the goal of increasing 

microbial drinking water protection for 

children. The public is invited to submit 

or identify peer-reviewed studies and 

data, of which EPA may not be aware 

that assessed results of early life 

exposure to DBPs. 

H. Executive Order 13211: Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

The proposed Stage 2 DBPR is not a 

‘‘significant energy action’’ as defined in 

Executive Order 13211, ‘‘Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use’’ (66 FR 28355 (May 

22, 2001)) because it is not likely to 

have a significant adverse effect on the 

supply, distribution, or use of energy. 

This determination is based on the 

following analysis. 

The first consideration is whether the 

Stage 2 DBPR would adversely affect the 

supply of energy. The Stage 2 DBPR 

does not regulate power generation, 

either directly or indirectly. The public 

and private utilities that the Stage 2 

DBPR regulates do not, as a rule, 

generate power. Further, the cost 

increases borne by customers of water 

utilities as a result of the Stage 2 DBPR 

are a low percentage of the total cost of 

water, except for a very few small 

systems that might install advanced 

technologies that must spread that cost 

over a narrow customer base. Therefore,

49656 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

the customers that are power generation 

utilities are unlikely to face any 

significant effects as a result of the Stage 

2 DBPR. In sum, the Stage 2 DBPR does 

not regulate the supply of energy, does 

not generally regulate the utilities that 

supply energy, and is unlikely 

significantly to affect the customer base 

of energy suppliers. Thus, the Stage 2 

DBPR would not translate into adverse 

effects on the supply of energy. 

The second consideration is whether 

the Stage 2 DBPR would adversely affect 

the distribution of energy. The Stage 2 

DBPR does not regulate any aspect of 

energy distribution. The utilities that are 

regulated by the Stage 2 DBPR already 

have electrical service. As derived later 

in this section, the proposed rule is 

projected to increase peak electricity 

demand at water utilities by only 0.007 

percent. Therefore, EPA estimates that 

the existing connections are adequate 

and that the Stage 2 DBPR has no 

discernable adverse effect on energy 

distribution. 

The third consideration is whether 

the Stage 2 DBPR would adversely affect 

the use of energy. Because some 

drinking water utilities are expected to 

add treatment technologies that use 

electrical power, this potential impact is 

evaluated in more detail. The analyses 

that underlay the estimation of costs for 

the Stage 2 DBPR are national in scope 

and do not identify specific plants or 

utilities that may install treatment in 

response to the rule. As a result, no 

analysis of the effect on specific energy 

suppliers is possible with the available 

data. The approach used to estimate the 

impact of energy use, therefore, focuses 

on national-level impacts. The analysis 

estimates the additional energy use due 

to the Stage 2 DBPR, and compares that 

to the national levels of power 

generation in terms of average and peak 

loads. 

The first step in the analysis is to 

estimate the energy used by the 

technologies expected to be installed as 

a result of the Stage 2 DBPR. Energy use 

is not directly stated in Technologies 

and Costs for Control of Microbial 

Contaminants and Disinfection ByProducts (USEPA 2003k), but the annual 

cost of energy for each technology 

addition or upgrade necessitated by the 

Stage 2 DBPR is provided. An estimate 

of plant-level energy use is derived by 

dividing the total energy cost per plant 

for a range of flows by an average 

national cost of electricity of $0.076/ 

kilowatt hours per year (kWh/yr) (U.S. 

Department of Energy, Energy 

Information Administration (USDOE 

EIA) 2002). These calculations are 

shown in detail in Chapter 8 of the 

Economic Analysis for the Stage 2 DBPR

(USEPA 2003i). The energy use per 

plant for each flow range and 

technology is then multiplied by the 

number of plants predicted to install 

each technology in a given flow range. 

The energy requirements for each flow 

range are then added to produce a 

national total. No electricity use is 

subtracted to account for the 

technologies that may be replaced by 

new technologies, resulting in a 

conservative estimate of the increase in 

energy use. Table VIII–3 shows the 

estimated energy use for each Stage 2 

DBPR compliance technology in 

kilowatt hours per year (kWh/yr). The 

incremental national annual energy 

usage is 0.08 million megawatt-hours 

(mWh).

To determine if the additional energy 

required for systems to comply with the 

rule would have a significant adverse 

effect on the use of energy, the numbers 

in Table VIII–3 are compared to the 

national production figures for 

electricity. According to the U.S. 

Department of Energy’s Information 

Administration, electricity producers 

generated 3,800 million mWh of 

electricity in 2001 (USDOE EIA 2002). 

Therefore, even using the highest 

assumed energy use for the Stage 2 

DBPR, the rule when fully implemented 

would result in only a 0.002 percent 

increase in annual average energy use. 

In addition to average energy use, the 

impact at times of peak power demand 

is important. To examine whether 

increased energy usage might 

significantly affect the capacity margins 

of energy suppliers, their peak season 

generating capacity reserve was 

compared to an estimate of peak


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incremental power demand by water 

utilities. 

Both energy use and water use peak 

in the summer months, so the most 

significant effects on supply would be 

seen then. In the summer of 2001, U.S. 

generation capacity exceeded 

consumption by 15 percent, or 

approximately 120,000 mW (USDOE 

EIA 2002). Assuming around-the-clock 

operation of water treatment plants, the 

total energy requirement can be divided 

by 8,760 hours per year to obtain an 

average power demand of 8.3 mW. A 

more detailed derivation of this value is 

shown in Chapter 8 of the Economic 

Analysis for the Stage 2 DBPR (USEPA 

2003i). Assuming that power demand is 

proportional to water flow through the 

plant and that peak flow can be as high 

as twice the average daily flow during 

the summer months, about 16.6 mW 

could be needed for treatment 

technologies installed to comply with 

the Stage 2 DBPR. This is only 0.014 

percent of the capacity margin available 

at peak use. 

Although EPA recognizes that not all 

areas have a 15 percent capacity margin 

and that this margin varies across 

regions and through time, this analysis 

reflects the effect of the rule on national 

energy supply, distribution, and use. 

While certain areas, notably California, 

have experienced shortfalls in 

generating capacity in the recent past, a 

peak incremental power requirement of 

16.6 mW nationwide is not likely to 

significantly change the energy supply, 

distribution, or use in any given area. 

Considering this analysis, EPA has 

concluded that Stage 2 DBPR will not 

have any significant effect on the use of 

energy, based on annual average use and 

on conditions of peak power demand. 

I. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act (NTTAA) of 1995, Pub. L. No. 104–

113, 12(d) (15 U.S.C. 272 note) directs 

EPA to use voluntary consensus 

standards in its regulatory activities 

unless to do so would be inconsistent 

with applicable law or otherwise 

impractical. Voluntary consensus 

standards are technical standards (e.g., 

materials specifications, test methods, 

sampling procedures, and business 

practices) that are developed or adopted 

by voluntary consensus standard bodies. 

The NTTAA directs EPA to provide 

Congress, through OMB, explanations 

when the Agency decides not to use 

available and applicable voluntary 

consensus standards. 

This proposed rulemaking involves 

technical standards. EPA proposes to 

use American Society for Testing and 

Materials (ASTM) Method D 6581–00 

for chlorite, bromide, and bromate 

compliance monitoring, which can be 

found in the Annual Book of ASTM 

Standards Volume 11.01. In the Stage 1 

DBPR, EPA approved 13 methods from 

the Standard Methods Committee for 

measuring disinfectants, DBPs, and 

other parameters. Today’s rule proposes 

to add the most recent versions of these 

13 methods as approved methods. These 

consist of Standard Methods 4500–Cl D, 

4500–Cl F, 4500–Cl G, 4500–Cl E, 4500–

Cl I, 4500–Cl H, 4500–ClO2 D, 4500–

ClO2 E, 6251 B, 5310 B, 5310 C, 5310 

D, and 5910 B for chlorine, chlorine 

dioxide, HAA5, chlorite, TOC/DOC, and 

UV254. These methods can be found in 

the 19th and 20th editions of Standard 

Methods for the Examination of Water 

and Waste Water (APHA 1995; APHA 

1996; APHA 1998). Standard Methods 

4500–Cl D, 4500–Cl F, 4500–Cl G, 4500–

Cl E, 4500–Cl I, 4500–Cl H, 4500–ClO2

E, 6251 B, 5310 B, 5310 C, 5310 D, and 

5910 B for chlorine, chlorine dioxide, 

HAA5, chlorite, TOC/DOC, and UV254

are also available in the On-Line 

Version of Standard Methods for the 

Examination of Water and Waste Water

(APHA 2003). 

EPA welcomes comments on this 

aspect of the proposed rulemaking and, 

specifically, invites the public to 

identify potentially applicable voluntary 

consensus standards and to explain why 

such standards should be used in this 

regulation. 

J. Executive Order 12898: Federal 

Actions to Address Environmental 

Justice in Minority Populations or Low 

Income Populations 

Executive Order 12898 establishes a 

Federal policy for incorporating 

environmental justice into Federal 

agency missions by directing agencies to 

identify and address disproportionately 

high and adverse human health or 

environmental effects of its programs, 

policies, and activities on minority and 

low-income populations. The Agency 

has considered environmental justice 

related issues concerning the potential 

impacts of this action and consulted 

with minority and low-income 

stakeholders. 

Two aspects of the Stage 2 DBPR 

comply with the order that requires the 

Agency to consider environmental 

justice issues in the rulemaking and to 

consult with stakeholders representing a 

variety of economic and ethnic 

backgrounds. These are: (1) The overall 

nature of the rule, and (2) the convening 

of a stakeholder meeting specifically to 

address environmental justice issues. 

The Stage 1 DBPR has served as a 

template for the development of the 

Stage 2 DBPR. As such, the Agency built 

on the efforts conducted during the 

development of the Stage 1 DBPR to 

comply with Executive Order 12898. On 

March 12, 1998, the Agency held a 

stakeholder meeting to address various 

components of pending drinking water 

regulations and how they might impact 

sensitive subpopulations, minority 

populations, and low-income 

populations. This meeting was a 

continuation of stakeholder meetings 

that started in 1995 to obtain input on 

the Agency’s Drinking Water Programs. 

Topics discussed included treatment 

techniques, costs and benefits, data 

quality, health effects, and the 

regulatory process. Participants were 

national, State, Tribal, municipal, and 

individual stakeholders. EPA conducted 

the meeting by video conference call 

between eleven cities. The major 

objectives for the March 12, 1998, 

meeting were the following: 

• Solicit ideas from stakeholders on 

known issues concerning current 

drinking water regulatory efforts; 

• Identify key areas of concern to 

stakeholders; and 

• Receive suggestions from 

stakeholders concerning ways to 

increase representation of communities 

in OGWDW regulatory efforts. 

In addition, EPA developed a plainEnglish guide for this meeting to assist 

stakeholders in understanding the 

multiple and sometimes complex issues 

surrounding drinking water regulations. 

The Stage 2 DBPR and other drinking 

water regulations promulgated or under 

development are expected to have a 

positive effect on human health 

regardless of the social or economic 

status of a specific population. The 

Stage 2 DBPR serves to provide a similar 

level of drinking water protection to all 

groups. Where water systems have high 

DBP levels, they must reduce levels to 

meet the MCLs. Thus, the Stage 2 DBPR 

meets the intent of Federal policy 

requiring incorporation of 

environmental justice into Federal 

agency missions. 

The Stage 2 DBPR applies uniformly 

to community water systems and 

nontransient noncommunity water 

systems that apply a chemical 

disinfectant or deliver water that has 

been chemically disinfected. 

Consequently, the health protection 

from DBP exposure that this rule 

provides is equal across all income and 

minority groups served by systems 

regulated by this rule.

49658 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

K. Consultations with the Science 

Advisory Board, National Drinking 

Water Advisory Council, and the 

Secretary of Health and Human Services 

In accordance with sections 1412 (d) 

and (e) of SDWA, the Agency has 

consulted with the Science Advisory 

Board (SAB), the National Drinking 

Water Advisory Council (NDWAC), and 

will consult with the Secretary of Health 

and Human Services regarding the 

proposed Stage 2 DBPR during the 

public comment period. 

EPA met with the SAB to discuss the 

Stage 2 DBPR on June 13, 2001 

(Washington, DC), September 25–26, 

2001 (teleconference), and December 

10–12, 2001 (Los Angeles, CA). Written 

comments from the December 2001 

meeting of the SAB addressing the 

occurrence analysis and risk assessment 

were generally supportive. EPA met 

with the NDWAC on November 8, 2001, 

in Washington, DC to discuss the Stage 

2 DBPR proposal. The Advisory 

Committee generally supported the need 

for the Stage 2 DBPR based on health 

and occurrence data, but also stressed 

the importance of providing flexibility 

to the systems implementing the rule. 

The results of these discussions are 

included in the docket for this rule. 

L. Plain Language 

Executive Order 12866 encourages 

Federal agencies to write rules in plain 

language. EPA invites comments on 

how to make this proposed rule easier 

to understand. For example: Has EPA 

organized the material to suit 

commenters’ needs? Are the 

requirements in the rule clearly stated? 

Does the rule contain technical language 

or jargon that is not clear? Would a 

different format (grouping and ordering 

of sections, use of headings, paragraphs) 

make the rule easier to understand? 

Could EPA improve clarity by adding 

tables, lists, or diagrams? What else 

could EPA do to make the rule easier to 

understand?

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Salhi, E. and von Gunten, U. 1999. 

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Bromate and Nitrite in Low μg l-1 Levels by 

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Induction of Reparative Hyperplasia in 

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1988. Developmental effects of 

trichloroacetic acid in Long-Evans rats. 

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40: 445–451. 

Smith, M.K., J.L. Randall, E.J. Read, and J.A. 

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Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49661

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M.A.Perei.1996.Loss of Heterozygosity on 

Chromosome 6 in Dichloroacetic Acid and 

Trichloroacetic Acid-Induced Liver 

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Lett. 108: 257–261. 

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1998. Effect of Dichloroacetic Acid and 

Trichloroacetic Acid on DNA Methylation 

in Liver and Tumors of Female B6C3F1

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and Rabbit. Toxicol. Appl. Pharmacol. 29, 

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and M.K. Smith, 1992. Adverse Male 

Reproductive Effects Following Subchronic 

Exposure of Rats to Sodium 

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57–63. 

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Reproductive and Developmental Toxicity 

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Triangle Institute. 

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(Billion Kilowatthours). http://

www.eia.doe.gov/emeu/mer/txt/mer7–1

USEPA 1979. National Interim Primary 

Drinking Water Regulations; Control of 

Trihalomethanes in Drinking Water. FR 

44:231:68624. (November 29, 1979). 

USEPA 1985. National Primary Drinking 

Water Regulations; Volatile Synthetic 

Organic Chemicals; Final Rule and 

Proposed Rule. FR 50:219:46880 

(September 13, 1985). 

USEPA 1986. Guidelines for Carcinogen Risk 

Assessment, FR 51:185:33992–34003. EPA/

600/8–87/045. NTIS PB88–123997. http://

www.epa.gov/ncea/raf/rafguid.htm

USEPA 1989a. National Primary Drinking 

Water Regulations; Filtration, Disinfection, 

Turbidity, Giardia lamblia, Viruses, 

Legionella, and Heterotrophic Bacteria; 

Final Rule. Part II. FR 54:124: 27486. (June 

29, 1989). 

USEPA 1989b. National Primary Drinking 

Water Regulations; Total Coliforms 

(Including Fecal Coliform and E. coli); 

Final Rule. FR 54:124: 27544. (June 29, 

1989). 

USEPA 1989c. Review of Environmental 

Contaminants and Toxicology. U.S. EPA. 

Office of Drinking Water Health 

Advisories. Volume 106. 225 pp. 

USEPA 1991a. National Primary Drinking 

Water Regulations; Synthetic Organic 

Chemicals and Inorganic Chemicals; 

Monitoring for Unregulated Contaminants; 

National Primary Drinking Water 

Regulations Implementation; National 

Secondary Drinking Water Regulations. 

Final rule, January 31, 1991. FR 56:20: 

3526. 

USEPA 1991b. Guidelines for Developmental 

Toxicity Risk Assessment. FR 

56:234:63798–63826. 

USEPA 1992. EPA Method 552.1. In Methods 

for the Determination of Organic 

Compounds in Drinking Water—

Supplement II. EPA 600/R–92/129. NTIS, 

PB92–207703. 

USEPA 1993. EPA Method 300.0. In Methods 

for the Determination of Inorganic 

Substances in Environmental Samples. 

EPA/600/R/93/100. 

USEPA 1994a. Draft Drinking Water Health 

Criteria Document for Chlorinated Acetic 

Acids/Alcohols/Aldehydes and Ketones. 

Office of Science and Technology, Office of 

Water. 

USEPA 1994b. National Primary Drinking 

Water Regulations; Disinfectants and 

Disinfection Byproducts; Proposed Rule. 

FR 59:145:38668–38829. (July 29, 1994). 

USEPA 1995. EPA Method 552.2. In Methods 

for the Determination of Organic 

Compounds in Drinking Water. 

Supplement III. EPA–600/R–95/131. NTIS, 

PB95261616. 

USEPA 1996a. National Primary Drinking 

Water Regulation: Monitoring 

Requirements for Public Drinking Water 

Supplies: Cryptosporidium, Giardia, 

Viruses, Disinfection Byproducts, Water 

Treatment Plant Data and Other 

Information Requirements. Final Rule. FR 

61:94:24354–24388. (May 14, 1996). 

USEPA 1996b. DBP/ICR Analytical Methods 

Manual. EPA 814–B–96–002. NTIS, PB96–

157516. 

USEPA 1997a. National Primary Drinking 

Water Regulations; Disinfectants and 

Disinfection Byproducts; Notice of Data 

Availability; Proposed Rule. FR 

62:212:59388–59484. (November 3, 1997).

USEPA 1997b. Manual for the Certification of 

Laboratories Analyzing Drinking Water. 

EPA 815–B–97–001. http://www.epa.gov/

OGWDW/certlab/labindex.html

USEPA 1998a. Quantification of Bladder 

Cancer Risk from Exposure to Chlorinated 

Surface Water. Office of Science and 

Technology, Office of Water. November 9, 

1998. 

USEPA 1998b. Health Risk Assessment/

Characterization of the Drinking Water 

Disinfection Byproduct Chloroform. Office 

of Science and Technology, Office of 

Water. EPA 815–B–98–006. PB 99–111346. 

USEPA 1998c. National Primary Drinking 

Water Regulations: Disinfectants and 

Disinfection Byproducts; Final Rule. FR 

63:241:69390–69476. (December 16, 1998). 

http://www.epa.gov/safewater/mdbp/

dbpfr.pdf

USEPA 1998d. National Primary Drinking 

Water Regulations: Interim Enhanced 

Surface Water Treatment Rule; Final Rule. 

FR 63:241:38832–38858. (December 16, 

1998). http://www.epa.gov/safewater/

mdbp/ieswtrfr.pdf

USEPA 1998e. National Primary Drinking 

Water Regulations; Disinfectants and 

Disinfection Byproducts; Notice of Data 

Availability; Proposed Rule. FR 

63:61:15606–15692. (March 31, 1998). 

USEPA 1998f. Regulatory Impact Analysis of 

Final Disinfectant/Disinfection ByProducts Regulations. Washington, DC. 

EPA Number 815–B–98–002. PB 99–

111304. 

USEPA 1998g. National-Level Affordability 

Criteria Under the 1996 Ammendments to 

the Safe Drinking Water Act (Final Draft 

Report). Contact 68–C6–0039. (August 19, 

1998). 

USEPA 1998h. Variance Technology 

Findings for Contaminants Regulated 

Before 1996. Office of Water. EPA 815–R–

98–003. 

USEPA 1998i. National Primary Drinking 

Water Regulations: Consumer Confidence 

Reports; Final Rule. FR 63:160:44512–

44536. 

USEPA 1998j. Revisions to State Primacy 

Requirements to Implement Safe Drinking 

Water Act Amendments; Final Rule. FR 

63:81:23362–23368. 

USEPA 1999a. Guidelines for carcinogen risk 

assessment. July SAB Review draft. Office 

of Research and Development, Washington, 

DC. USEPA NCEA–F–0644. http://

www.epa.gov/ncea/raf/crasab.htm

USEPA 1999b. National Primary and 

Secondary Drinking Water Regulations: 

Analytical Methods for Chemical and 

Microbiological Contaminants and 

Revisions to Laboratory Certification 

Requirements; Final Rule. FR 

64:230:67449. (December 1, 1999). 

USEPA 1999c. Chloroform Mode of Action 

Analysis. Prepared for the Science 

Advisory Board by Office of Science and 

Technology, Office of Water. October 1999. 

http://www.epa.gov/sab/chloro00.htm

USEPA 1999d. Cost of Illness Handbook. 

Office of Pollution Prevention and Toxics. 

Chapter 1 II.8. Cost of Bladder Cancer. 

September, 1999. http://www.epa.gov/

oppt/coi

USEPA 2000a. Estimated per Capita Water 

Ingestion in the United States. EPA–

82200–008. http://www.epa.gov/

waterscience/drinking/percapita/

USEPA 2000b. Guidelines for Preparing 

Economic Analyses. Washington, DC. EPA 

240R–00–003, September 2000. 

USEPA 2000c. Information Collection Rule 

Auxiliary 1 Database, Version 5, EPA 815–

C–00–002, April 2000. 

USEPA 2000d. EPA Method 321.8. In 

Methods for the Determination of Organic 

and Inorganic Compounds in Drinking 

Water, Volume 1. ORD–NERL, Cincinnati, 

OH. EPA 815–R–00–014. Available on 

ORD–NERL Web site at http://

www.epa.gov/nerlcwww/ordmeth.htm.

USEPA 2000e. Removal of the Maximum 

Contaminant Level Goal for Chloroform 

From the National Primary Drinking Water 

Regulations. FR 65:104:34404–34405. (May 

30, 2000). http://www.epa.gov/safewater/

regs/chlorfr.html

USEPA 2000f. Review of the EPA’s Draft 

Chloroform Risk Assessment by a 

Subcommittee of the Science Advisory 

Board. Science Advisory Board, 

Washington, DC. EPA–SAB–EC–00–009. 

USEPA 2000g. Stage 2 Microbial and 

Disinfection Byproducts Federal Advisory 

Committee Agreement in Principle. FR 

65:251:83015–83024. (December 29, 2000). 

http://www.epa.gov/fedrgstr/EPA–WATER/

2000/December/Day-29/w33306.htm

USEPA 2000h. National Primary Drinking 

Water Regulations: Ground Water Rule. 

Proposed Rules. FR 65:91:30194–30274. 

(May 10, 2000). 

USEPA 2000i. Quantitative Cancer 

Assessment for MX and 

Chlorohydroxyfuranones. Contract NO. 68–

C–98–195. August 11, 2000, Office of 

Water, Office of Science and Technology, 

Health and Ecological Criteria Division, 

Washington, DC.

49662 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

USEPA 2000j. Drinking Water Baseline 

Handbook, Second Edition. Prepared by 

International Consultants, Inc. under 

contract with EPA OGWDW, Standards 

and Risk Management Division. March 17, 

2000. 

USEPA 2000k. Geometries and 

Characteristics of Public Water Systems. 

Final Report. EPA 815–R–00–024. 

December 2000.

USEPA 20001. EPA Method 300.1. In 

Methods for the Determination of Organic 

and Inorganic Compounds in Drinking 

Water, Volume 1. OW–OGWDW–TSC, 

Cincinnati, OH. EPA 815–R–00–014. 

Available on the OGWDW Web site at 

http://www.epa.gov/safewater/methods/

sourcalt.html.

USEPA 2000m. Information Collection Rule 

Treatment Study Database CD–ROM, 

Version 1.0. 

USEPA 2000n. Science Advisory Board Final 

Report. Prepared for Environmental 

Economics Advisory Committee. July 27, 

2000. EPA–SAB–EEAC–00–013. 

USEPA 2000o. Draft Dioxin Reassessment. 

EPA/600/P–00/001B http://cfpub.epa.gov/

ncea/cfm/part1and2.cfm?ActType=default.

USEPA 2001a. Relative Source Contribution 

for Chloroform. EPA–822-R–01–006. 

USEPA 2001b. Toxicological Review of 

Chloroform. In support of Integrated Risk 

Information System (IRIS). Washington, 

DC. Draft. EPA/635/R–01/001. 

USEPA 2001c. National Primary Drinking 

Water Regulations: Filter Backwash 

Recycling Rule. Final Rule. FR 

66:111:31086–31105. (June 8, 2001). 

USEPA 2001d. Method 317.0, Revision 2.0. 

Determination of Inorganic Oxyhalide 

Disinfection By-Products in Drinking 

Water Using Ion Chromatography with the 

Addition of a Postcolumn Reagent for 

Trace Bromate Analysis. Revision 2.0. EPA 

815–B–01–001. (Available on the OGWDW 

Web site at http://www.epa.gov/safewater/

methods/sourcalt.html.)

USEPA 2001e. Arsenic Rule Benefits 

Analysis: an SAB Review. August 30, 2001. 

EPA–SAB–EC–01–008. 

USEPA 2002a. Method 326.0. Determination 

of Inorganic Oxyhalide Disinfection ByProducts in Drinking Water Using Ion 

Chromatography Incorporating the 

Addition of a Suppressor Acidified 

Postcolumn Reagent for Trace Bromate 

Analysis. Revision 1.0. EPA 815–R–03–

007. (Available on the OGWDW Web site 

at http://www.epa.gov/safewater/methods/

sourcalt.html.)

USEPA 2002b. Long Term 1 Enhanced 

Surface Water Treatment Rule. January 14, 

2002. 67 FR 1812. 

USEPA 2002c. Affordability Criteria for 

Small Drinking Water Systems: an EPA 

Science Advisory Board Report. December 

2002. EPA–SAB–EEAC–03–004. 

USEPA 2003a. Health Risks to Fetuses, 

Infants, and Children: A Review. Office of 

Water, Office of Science and Technology, 

Health and Ecological Criteria Division. 

USEPA 2003b. Addendum to the Criteria 

Document for Monochloroacetic Acid and 

Trichleoeacetic Acid: External Review 

Draft. 

USEPA 2003c. Addendum to the Criteria 

Document for Dichloroacetic Acid: 

External Review Draft. 

USEPA 2003d. Drinking Water Criteria 

Document for Brominated 

Trihalomethanes: External Review Draft. 

USEPA 2003e. Drinking Water Criteria 

Document for Brominated Haloacetic 

Acids: External Review Draft. 

USEPA 2003f. Drinking Water Criteria 

Document for Cyanogen Chloride, External 

Review Draft. 

USEPA 2003g. Drinking Water Criteria 

Document for Glyoxal and Methylglyoxal: 

External Review Draft. 

USEPA 2003h. Drinking Water Criteria 

Document for Haloacetonitriles: External 

Review Draft. 

USEPA 2003i. Economic Analysis for the 

Proposed Stage 2 DBPR. Washington, DC. 

EPA 815–D–03–001. 

USEPA 2003j. Draft Initial Distribution 

System Evaluation Guidance Manual. 

Washington, DC. EPA 815–D–03–002. 

USEPA 2003k. Technologies and Costs for 

Control of Microbial Pathogens and 

Disinfection Byproducts. Prepared by the 

Cadmus Group and Malcolm Pirnie. 

USEPA 2003l. Toxicologcal Review for 

Dichloroacetic Acid: Consensus Review 

Draft. http://www.epa.gov/iris/subst/

0654.htm

USEPA 2003m. Information Collection 

Request. Washington, DC. EPA 815–D–03–

003. 

USEPA 2003n. Draft Significant Excursion 

Guidance Manual. Washington, DC. EPA 

815–D–03–004. 

USEPA 2003o. Stage 2 Occurrence 

Assessment for Disinfectants and 

Disinfection Byproducts (D/DBPs). EPA 

68–C–99–206. 

USEPA 2003p. Method 552.3. Determination 

of Haloacetic Acids and Dalapon in 

Drinking Water by Liquid-liquid 

Extraction, Derivatization, and Gas 

Chromatography with Electron Capture 

Detection. Revision 1.0. (Available on the 

OGWDW Web site at http://www.epa.gov/

safewater/methods/sourcalt.html.)

USEPA 2003q. Method 327.0. Determination 

of Chlorine Dioxide and Chlorite Ion in 

Drinking water Using Lissamine Green B 

and Horseradish Peroxidase with Detection 

by Visible Spectrophotometry. Revision 

1.0. (Available on the OGWDW Web site at 

http://www.epa.gov/safewater/methods/

sourcalt.html.)

USEPA 2003r. Method 415.3. Determination 

of Total Organic Carbon, and Specific UV 

Absorbance at 254 nm in Source Water and 

Drinking Water. Revision 1.0. NERL, 

Cincinnati, OH 45268.

USEPA 2003s. Arsenic in Drinking Water: 

Cessation Lag Model. Prepared by Sciences 

International. Contract No. 68–c–98–195. 

January, 2003. 

Veeramachaneni, D.N.R., T.T. Higuchi, J.S. 

Palmer, and C.M. Kane. 2000. 

Dibromoacetic Acid, a Disinfection Byproduct in Drinking Water, Impairs Sexual 

Function and Fertility in Male Rabbits. 

Paper presented at the annual meeting for 

the Society for the Study of Reproduction, 

Madison, Wisconsin. 

Vena, JE, Graham, S, Freudenheim, J, 

Marshall, J, Zielezny, M, Swanson, M, 

Sufrin, G. 1993. Drinking water, fluid 

intake, and bladder cancer in western New 

York. Archives of Environmental Health, 

48(3):191–8. 

Ventura, S.J., W.D. Mosher, S.C. Curtin, J.C. 

Abma, and S. Henshaw. 2000. ‘‘Trends in 

Pregnancies and Pregnancy Rates by 

Outcome: Estimates for the United States, 

1976–96.’’ National Center for Health 

Statistics. Vital Health Stat 21(56). 

Villanueva, C.M., F. Fernandez, N. Malats, 

J.O. Grimalt, M. Kogevinas. 2003. Metaanalysis of Studies on Individual 

Consumption of Chlorinated Drinking 

Water and Bladder Cancer. J Epidemiol 

Community Health, 57:166–173. 

Wagner, H.P., Pepich, B.V., Frebis, C., 

Hautman, D.P., Munch, D.J., and Jackson, 

P.E. 2001. A Collaborative Study of EPA 

Method 317.0 for the Determination of 

Inorganic Oxyhalide Disinfection ByProducts in Drinking Water using Ion 

Chromatography with the Addition of a 

Postcolumn Reagent for Trace Bromate 

Analysis. Journal of Chromatographic 

Science. Vol 39 (255–259), June 2001. 

Wagner, H.P., Pepich, B.V., Frebis, C., 

Hautman, D.P. and Munch, D.J. 2002. U.S. 

Environmental Protection Agency Method 

326.0, a new method for monitoring 

inorganic oxyhalides and optimization of 

the postcolumn derivatization for the 

selective determination of trace levels of 

bromate. Journal of Chromatography. A. 

Vol. 956 (93–101), May 2002. 

Wallace, L.A. 1997. Human exposure and 

Body Burden for Chloroform and Other 

Trihalomethanes., Crit. Rev. Environ. Sci. 

Technol. 27:113–94. 

Waller, K., S.H. Swan, G. DeLorenze, B. 

Hopkins. 1998. Trihalomethanes in 

Drinking Water and Spontaneous Abortion. 

Epidemiology. 9(2):134–140. 

Waller, K., S.H. Swan, G.C. Windham, L. 

Fenster. 2001. Influence of Exposure 

Assessment Methods on Risk Estimates in 

an Epidemiologic Study of Total 

Trihalomethane Exposure and 

Spontaneous Abortion. Journal of Exposure 

Analysis and Environmental 

Epidemiology. 11(6): 522–531. 

Weisel, C.P. and W.K. Jo. 1996. Ingestion, 

Inhalation, and Dermal Exposures to 

Chloroform and Trichloroethene from Tap 

Water. Environmental Health Perspectives. 

104 (1): 48–51. 

WHO 2000. World Health Organization, 

International Programme on Chemical 

Safety (IPCS). Environmental Health 

Criteria 216: Disinfectants and Disinfectant 

By-products. 

Williams, S.L., Rindfleisch, D.F., and 

Williams, RL. 1995. Deadend on Haloacetic 

Acids (HAA). In Proceedings of the 1994 

AWWA Water Quality Technology 

Conference, November 1994. 

Windham GC, Waller K, Anderson M, 

Fenster L, Mendola P, Swan S. 2003. 

Chlorination by-Products in Drinking 

Water and Menstrual Cycle Function. 

Environ Health Perspect: doi:10.1289/

ehp.5922. http://ehpnet1.niehs.nih.gov/

docs/2003/5922/abstract.html

Yang, C.Y., H.F. Chiu, M.F. Cheng, et al.

1998. Chlorination of Drinking Water and 

Cancer Mortality in Taiwan. 

Environmental Research 78(1):1–6.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49663

Yang, V., B. Cheng, S. Tsai, T. Wu, M. Lin 

M. and K. Lin. 2000. Association between 

Chlorination of Drinking Water and 

Adverse Pregnancy Outcome in Taiwan. 

Environ. Health. Perspect. 108:765–68. 

Zheng, M., S. Andrews, and J. Bolton. 1999. 

Impacts of medium-pressure UV on THM 

and HAA formation in pre-UV chlorinated 

drinking water. Proceedings, Water Quality 

Technology Conference of the American 

Water Works Association, Denver, CO.

List of Subjects 

40 CFR Part 141 

Chemicals, Indians-lands, 

Intergovernmental relations, Radiation 

protection, Reporting and recordkeeping 

requirements, Water supply. 

40 CFR Part 142 

Administrative practice and 

procedure, Chemicals, Indians-lands, 

Radiation protection, Reporting and 

recordkeeping requirements, Water 

supply. 

40 CFR Part 143 

Chemicals, Indians-lands, Water 

supply.

Dated: July 11, 2003. 

Linda J. Fisher, 

Acting Administrator.

For the reasons set forth in the 

preamble, title 40 chapter I of the Code 

of Federal Regulations is proposed to be 

amended as follows:

PART 141—NATIONAL PRIMARY 

DRINKING WATER REGULATIONS 

1. The authority citation for part 141 

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g–1, 300g–2, 

300g–3, 300g–4, 300g–5, 300g–6, 300j–4, 

300j–9, and 300j–11.

2. Section 141.2 is amended by 

adding, in alphabetical order, 

definitions for ‘‘Combined distribution 

system’’, ‘‘Consecutive system’’, 

‘‘Consecutive system entry point’’, 

‘‘Dual sample sets’’, ‘‘Finished water’’, 

‘‘Locational running annual average’’, 

and ‘‘Wholesale system’’ to read as 

follows:

§ 141.2 Definitions.

* * * * *

Combined distribution system is the 

interconnected distribution system 

consisting of the distribution systems of 

wholesale systems and of the 

consecutive systems that receive 

finished water from those wholesale 

system(s).

* * * * *

Consecutive system is a public water 

system that buys or otherwise receives 

some or all of its finished water from 

one or more wholesale systems, for at 

least 60 days per year. 

Consecutive system entry point is a 

location at which finished water is 

delivered at least 60 days per year from 

a wholesale system to a consecutive 

system.

* * * * *

Dual sample set is a set of two 

samples collected at the same time and 

same location, with one sample 

analyzed for TTHM and the other 

sample analyzed for HAA5. Dual sample 

sets are collected for the purposes of 

conducting an IDSE under subpart U of 

this part and determining compliance 

with the TTHM and HAA5 MCLs under 

subpart V of this part.

* * * * *

Finished water is water that is 

introduced into the distribution system 

of a public water system and is intended 

for distribution without further 

treatment, except that necessary to 

maintain water quality.

* * * * *

Locational running annual average

(LRAA) is the average of sample 

analytical results for samples taken at a 

particular monitoring site during the 

previous four calendar quarters.

* * * * *

Stage 2A is the period beginning [date 

three years following publication of the 

final rule] until the dates specified in 

subpart V of this part for compliance 

with Stage 2B, during which systems 

must comply with Stage 2A MCLs in 

§ 141.64(b)(2).

* * * * *

Wholesale system is a public water 

system that treats source water and then 

sells or otherwise delivers finished 

water to another public water system for 

at least 60 days per year. Delivery may 

be through a direct connection or 

through the distribution system of one 

or more consecutive systems. 

3. In § 141.23, the table in paragraph 

(k)(1) is amended by revising entries 13, 

18, 19, and 20; revising the 

undesignated text after the table; and 

adding a new footnote 19 to read as 

follows:

§ 141.23 Inorganic chemical sampling and 

analytical requirements.

* * * * *

(k) Inorganic analysis:

* * * * *

Contaminant and methodology 13 EPA ASTM 3 SM 4 (18th, 19th 

ed.) SM 4 (20th ed.) Other 

* * * * * * * 

13. Fluoride: 

Ion Chromatography ................................................ 6 300.0 D4327–97 4110 B 4110 B 19 300.1 

Manual Distill.; Color. SPADNS. ............................. .................. . 4500–F B, D 4500–F B, D 

Manual Electrode .................................................... .................. D1179–93B 4500–F C 4500–F C 

Automated Electrode ............................................... .................. . . . 380–75WE11

Automated Alizarin .................................................. .................. . 4500–F E 4500–F E 129–71W 11

* * * * * * * 

18. Nitrate: 

Ion Chromatography ................................................ 6 300.0 D4327–97 4110 B 4110 B B1011 8

19 300.1 

Automated Cadmium Reduction ............................. 6 353.2 D3867–90A 4500–NO3 F 4500–NO3 F 

Ion Selective Electrode ........................................... .................. . 4500–NO3 D 4500–NO3 D 601 7

Manual Cadmium Reduction ................................... .................. D3867–90B 4500–NO3 E 4500–NO3 E 

19. Nitrite: 

Ion Chromatography ................................................ 6 300.0 D4327–97 4110 B 4110 B B–10118

19 300.1 

Automated Cadmium Reduction ............................. 6 353.2 D3867–90A 4500–NO3 F 4500–NO3 F 

Manual Cadmium Reduction ................................... .................. D3867–90B 4500–NO3 E 4500–NO3 E 

Spectrophotometric ................................................. .................. 4500–NO2 B 4500–NO2 B 

20. Orthophosphate: 12

49664 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

Contaminant and methodology 13 EPA ASTM 3 SM 4 (18th, 19th 

ed.) SM 4 (20th ed.) Other 

Colorimetric, automated, ascorbic acid ................... 6365.1 . 4500–P F 4500–P F 

Colorimetric, ascorbic acid, single reagent ............. .................. D515–88A 4500–P E 4500–P E 

Colorimetric, phosphomolybdate ............................. .................. ...I–1601–855

Automated–segmented flow .................................... .................. ...I–2601–905

Automated discrete ................................................. .................. ...I–2598–855

Ion Chromatography ................................................ 6 300.0 D4327–97 4110 B 4110 B 19 300.1 

* * * * * * * 

Note: The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1–11 and 16–19 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 

part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800–426–4791. Documents may be inspected at EPA’s Drinking Water Docket, EPA West, 1301 

Constitution Avenue NW., Room B102, Washington, DC 20460 (Telephone: 202–566–2426); or at the Office of the Federal Register, 800 North 

Capitol Street, NW., Suite 700, Washington, DC. 

* * * * * * * 

3Annual Book of ASTM Standards, 1994, 1996, or 1999, Vols. 11.01 and 11.02, ASTM International; any year containing the cited version of 

the method may be used. The previous versions of D1688–95A, D1688–95C (copper), D3559–95D (lead), D1293–95 (pH), D1125–91A (conductivity) and D859–94 (silica) are also approved. These previous versions D1688–90A, C; D3559–90D, D1293–84, D1125–91A and D859–88, respectively are located in the Annual Book of ASTM Standards, 1994, Vol. 11.01. Copies may be obtained from ASTM International, 100 Barr 

Harbor Drive, West Conshohocken, PA 19428. 4Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998). American 

Public Health Association, 1015 Fifteenth Street, NW, Washington, DC 20005. The cited methods published in any of these three editions may 

be used, except that the versions of 3111 B, 3111 D, 3113 B and 3114 B in the 20th edition may not be used. 5 Method I–2601–90, Methods for Analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of Inorganic and 

Organic Constituents in Water and Fluvial Sediment, Open File Report 93–125, 1993; For Methods I–1030–85; I–1601–85; I–1700–85; I–2598–

85; I–2700–85; and I–3300–85 See Techniques of Water Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A–1, 3rd ed., 

1989; Available from Information Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225–0425. 6 ‘‘Methods for the Determination of Inorganic Substances in Environmental Samples’’, EPA/600/R–93/100, August 1993. Available at NTIS, 

PB94–120821. 7The procedure shall be done in accordance with the Technical Bulletin 601 ‘‘Standard Method of Test for Nitrate in Drinking Water’’, July 

1994, PN 221890–001, Analytical Technology, Inc. Copies may be obtained from ATI Orion, 529 Main Street, Boston, MA 02129. 8 Method B–1011, ‘‘Waters Test Method for Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography,’’ August 1987. 

Copies may be obtained from Waters Corporation, Technical Services Division, 34 Maple Street, Milford, MA 01757. 

* * * * * * * 

11 Industrial Method No. 129–71W, ‘‘Fluoride in Water and Wastewater’’, December 1972, and Method No. 380–75WE, ‘‘Fluoride in Water and 

Wastewater’’, February 1976, Technicon Industrial Systems. Copies may be obtained from Bran & Luebbe, 1025 Busch Parkway, Buffalo Grove, 

IL 60089. 12 Unfiltered, no digestion or hydrolysis. 13Because MDLs reported in EPA Methods 200.7 and 200.9 were determined using a 2X preconcentration step during sample digestion, 

MDLs determined when samples are analyzed by direct analysis (i.e., no sample digestion) will be higher. For direct analysis of cadmium and arsenic by Method 200.7, and arsenic by Method 3120 B sample preconcentration using pneumatic nebulization may be required to achieve lower 

detection limits. Preconcentration may also be required for direct analysis of antimony, lead, and thallium by Method 200.9; antimony and lead by 

Method 3113 B; and lead by Method D3559–90D unless multiple in-furnace depositions are made. 

* * * * * * * 

19 ‘‘Methods for the Determination of Organic and Inorganic Compounds in Drinking Water’’, Vol. 1, EPA 815–R–00–014, August 2000. Available at NTIS, PB2000–106981. 

* * * * *

4. Section 141.24 is amended by 

revising paragraph (e)(1) and by revising 

entry 30 in the table in paragraph (e)(1) 

to read as follows:

§ 141.24 Organic chemicals, sampling and 

analytical requirements.

* * * * *

(e) * * *

(1) The following documents are 

incorporated by reference. This 

incorporation by reference was 

approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR Part 51. Copies may 

be inspected at EPA’s Drinking Water 

Docket, 1301 Constitution Avenue, NW., 

EPA West, Room B102, Washington, DC 

20460 (Telephone: 202–566–2426); or at 

the Office of the Federal Register, 800 

North Capitol Street, NW., Suite 700, 

Washington, DC. Method 508A and 

515.1 are in Methods for the 

Determination of Organic Compounds 

in Drinking Water, EPA/600/4–88–039, 

December 1988, Revised, July 1991. 

Methods 547, 550 and 550.1 are in 

Methods for the Determination of 

Organic Compounds in Drinking 

Water—Supplement I, EPA/600–4–90–

020, July 1990. Methods 548.1, 549.1, 

552.1 and 555 are in Methods for the 

Determination of Organic Compounds 

in Drinking Water—Supplement II, 

EPA/600/R–92–129, August 1992. 

Methods 502.2, 504.1, 505, 506, 507, 

508, 508.1, 515.2, 524.2 525.2, 531.1, 

551.1 and 552.2 are in Methods for the 

Determination of Organic Compounds 

in Drinking Water—Supplement III, 

EPA/600/R–95–131, August 1995. 

Method 1613 is titled ‘‘Tetra-through 

Octa-Chlorinated Dioxins and Furans by 

Isotope-Dilution HRGC/HRMS’’, EPA/

821–B–94–005, October 1994. These 

documents are available from the 

National Technical Information Service, 

NTIS PB91–231480, PB91–146027, 

PB92–207703, PB95–261616 and PB95–

104774, U.S. Department of Commerce, 

5285 Port Royal Road, Springfield, 

Virginia 22161. The toll-free number is 

800–553–6847. Method 6651 shall be 

followed in accordance with Standard 

Methods for the Examination of Water 

and Wastewater, 18th edition (1992), 

19th edition (1995), or 20th edition 

(1998), American Public Health 

Association (APHA); any of these three 

editions may be used. Method 6610 

shall be followed in accordance with 

Standard Methods for the Examination 

of Water and Wastewater, (18th Edition 

Supplement) (1994), or with the 19th 

edition (1995) or 20th edition (1998) of 

Standard Methods for the Examination 

of Water and Wastewater; any of these 

publications may be used. The APHA 

documents are available from APHA, 

1015 Fifteenth Street NW., Washington, 

D.C. 20005. Other required analytical 

test procedures germane to the conduct

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49665

of these analyses are contained in 

Technical Notes on Drinking Water 

Methods, EPA/600/R–94–173, October 

1994, NTIS PB95–104766. EPA Methods 

515.3 and 549.2 are available from U.S. 

Environmental Protection Agency, 

National Exposure Research Laboratory 

(NERL)—Cincinnati, 26 West Martin 

Luther King Drive, Cincinnati, OH 

45268. ASTM Method D 5317–93 is 

available in the Annual Book of ASTM 

Standards, (1999), Vol. 11.02, ASTM 

International, 100 Barr Harbor Drive, 

West Conshohocken, PA 19428, or in 

any edition published after 1993. EPA 

Method 515.4, ‘‘Determination of 

Chlorinated Acids in Drinking Water by 

Liquid-Liquid Microextraction, 

Derivatization and Fast Gas 

Chromatography with Electron Capture 

Detection,’’ Revision 1.0, April 2000, 

EPA/815/B–00/001 and EPA Method 

552.3, ‘‘Determination of Haloacetic 

Acids and Dalapon in Drinking Water 

by Liquid-Liquid Microextraction, 

Derivatization, and Gas Chromatography 

with Electron Capture Detection,’’

Revision 1.0, July 2003 can be accessed 

and downloaded directly on-line at 

http://www.epa.gov/safewater/methods/

sourcalt.html. The Syngenta AG–625, 

‘‘Atrazine in Drinking Water by 

Immunoassay’’, February 2001 is 

available from Syngenta Crop 

Protection, Inc., 410 Swing Road, Post 

Office Box 18300, Greensboro, NC 

27419, Phone number (336) 632–6000. 

Method 531.2 ‘‘Measurement of Nmethylcarbamoyloximes and Nmethylcarbamates in Water by Direct 

Aqueous Injection HPLC with 

Postcolumn Derivatization,’’ Revision 

1.0, September 2001, EPA 815/B/01/002 

can be accessed and downloaded 

directly on-line at http://www.epa.gov/

safewater/methods/sourcalt.html.

Contaminant EPA method 1 Standard methods ASTM Other 

* * * * * * * 

30. Dalapon .............................................................................. 552.1, 515.1, 

552.2, 515.3, 

515.4, 552.3 

* * * * * * * 

1For previously approved EPA methods which remain available for compliance monitoring until June 1, 2001, see paragraph (e)(2) of this 

section. 

* * * * *

5. Section 141.33 is amended by 

revising the first sentence of paragraph 

(a) introductory text, and adding 

paragraph (f) to read as follows:

§ 141.33 Record maintenance.

* * * * *

(a) Records of microbiological 

analyses and turbidity analyses made 

pursuant to this part shall be kept for 

not less than 5 years. * * *

* * * * *

(f) Copies of monitoring plans 

developed pursuant to this part shall be 

kept for the same period of time as the 

records of analyses are required to be 

kept under paragraph (a) of this section 

or for three years after modification, 

whichever is longer. 

6. Section 141.53 is amended by 

revising the table to read as follows:

§ 141.53 Maximum contaminant level goals 

for disinfection byproducts.

* * * * *

Disinfection byproduct MCLG (mg/L) 

Bromodichloromethane zero. 

Bromoform zero. 

Bromate zero. 

Chlorite 0.8

Chloroform 0.07

Dibromochloromethane 0.06

Dichloroacetic acid zero. 

Monochloroacetic acid 0.03

Trichloroacetic acid 0.02

7. Section 141.64 is revised to read as 

follows:

§ 141.64 Maximum contaminant levels for 

disinfection byproducts.

(a) Bromate and chlorite. The 

maximum contaminant levels (MCLs) 

for bromate and chlorite are as follows:

Disinfection byproduct MCL (mg/L) 

Bromate .................................... 0.010 

Chlorite ..................................... 1.0 

(1) Compliance dates for CWSs and 

NTNCWSs. Subpart H systems serving 

10,000 or more persons must comply 

with this paragraph (a) beginning 

January 1, 2002. Subpart H systems 

serving fewer than 10,000 persons and 

systems using only ground water not 

under the direct influence of surface 

water must comply with this paragraph 

(a) beginning January 1, 2004. 

(2) Best available technology. The 

Administrator, pursuant to section 1412 

of the Act, hereby identifies the 

following as the best technology, 

treatment techniques, or other means 

available for achieving compliance with 

the maximum contaminant levels for 

bromate and chlorite identified in this 

paragraph (a):

Disinfection 

byproduct Best available technology 

Bromate ...... Control of ozone treatment 

process to reduce production bromate. 

Disinfection 

byproduct Best available technology 

Chlorite ....... Control of treatment processes 

to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant 

levels. 

(b) TTHM and HAA5.

(1) Subpart L—RAA compliance. (i) 

Compliance dates. Subpart H systems 

serving 10,000 or more persons must 

comply with this paragraph (b)(1) 

beginning January 1, 2002 until the date 

specified for subpart V of this part 

compliance in § 141.620(c). Subpart H 

systems serving fewer than 10,000 

persons and systems using only ground 

water not under the direct influence of 

surface water must comply with this 

paragraph (b)(1) beginning January 1, 

2004 until the date specified for subpart 

V of this part compliance in 

§ 141.620(c).

Disinfection byproduct MCL 

(mg/L) 

Total trihalomethanes (TTHM) ....... 0.080 

Haloacetic acids (five) (HAA5) ....... 0.060 

(ii) Best available technology. The 

Administrator, pursuant to section 1412 

of the Act, hereby identifies the 

following as the best technology, 

treatment techniques, or other means

49666 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

available for achieving compliance with 

the maximum contaminant levels for 

TTHM and HAA5 identified in this 

paragraph (b)(1):

Disinfection byproduct Best available 

technology 

Total trihalomethanes 

(TTHM) and 

Halaocetic acids 

(five) (HAA5).

Enhanced coagulation or enhanced 

softening or 

GAC10, with chlorine as the primary 

and residual 

disinfectant. 

(2) Stage 2A—LRAA compliance. (i) 

Compliance dates. The Stage 2A MCLs 

for TTHM and HAA5 must be complied 

with as a locational running annual 

average at each subpart L of this part 

compliance monitoring location under 

§ 141.136 beginning [date three years 

after publication of the final rule] until 

the date specified for subpart V of this 

part compliance in § 141.620(c).

Disinfection byproduct MCL 

(mg/L) 

Total trihalomethanes (TTHM) ....... 0.120 

Haloacetic acids (five) (HAA5) ....... 0.100 

(ii) Best available technology. The 

Administrator, pursuant to section 1412 

of the Act, hereby identifies the 

following as the best technology, 

treatment techniques, or other means 

available for achieving compliance with 

the maximum contaminant levels for 

TTHM and HAA5 identified in this 

paragraph (b)(2):

Disinfection 

byproduct 

Best available 

technology 

Total 

trihalomethanes 

(TTHM) and 

Haloacetic acids 

(five) (HAA5).

Enhanced coagulation 

or enhanced softening or GAC10, with 

chlorine as the primary and residual 

disinfectant. 

(3) Subpart V LRAA compliance. (i) 

Compliance dates. The subpart V of this 

part MCLs for TTHM and HAA5 must 

be complied with as a locational 

running annual average at each 

monitoring location beginning the date 

specified for Subpart V of this part 

compliance in § 141.620(c).

Disinfection byproduct MCL 

(mg/L) 

Total trihalomethanes (TTHM) ....... 0.080 

Haloacetic acids (five) (HAA5) ....... 0.060 

(ii) Best technology for systems that 

disinfect their source water. The 

Administrator, pursuant to section 1412 

of the Act, hereby identifies the 

following as the best technology, 

treatment techniques, or other means 

available for achieving compliance with 

the maximum contaminant levels for 

TTHM and HAA5 identified in this 

paragraph (b)(3) for all systems that 

disinfect their source water:

Disinfection 

byproduct Best available technology 

Total 

trihalomethanes (TTHM) 

and 

Haloacetic 

acids (five) 

(HAA5).

Enhanced coagulation or 

enhanced softening, plus 

GAC10; or nanofiltration 

with a molecular weight 

and cutoff ≤1000 Daltons; or GAC20. 

(iii) Best available technology for 

systems that buy disinfected water. The 

Administrator, pursuant to section 1412 

of the Act, hereby identifies the 

following as the best technology, 

treatment techniques, or other means 

available for achieving compliance with 

the maximum contaminant levels for 

TTHM and HAA5 identified in this 

paragraph (b)(3) for systems that buy 

disinfected water:

Disinfection 

byproduct Best available technology 

Total 

trihalomethanes (TTHM) 

and 

Haloacetic 

acids (five) 

(HAA5).

Improved distribution system and storage tank 

management to reduce 

detention time plus the 

use of chloramines for 

disinfectant residual 

maintenance. 

(c) Extensions. A system that is 

installing GAC or membrane technology 

to comply with the MCLs in paragraphs 

(a) or (b)(1) of this section may apply to 

the State for an extension of up to 24 

months past January 1, 2002, but not 

beyond January 1, 2004. In granting the 

extension, States must set a schedule for 

compliance and may specify any 

interim measures that the system must 

take. Failure to meet the schedule or any 

interim treatment requirements 

constitutes a violation of a National 

Primary Drinking Water Regulation.

Subpart L—[Amended] 

8. Section 141.131 is amended by 

revising paragraphs (a), (b), (d)(2), (d)(3), 

(d)(4)(i), (d)(4)(ii), and the table in 

paragraph (c)(1), and adding paragraph 

(d)(6) to read as follows:

§ 141.131 Analytical requirements. 

(a) General. (1) Systems must use only 

the analytical methods specified in this 

section, or their equivalent as approved 

by EPA, to demonstrate compliance 

with the requirements of this subpart 

and with the requirements of subparts U 

and V. These methods are effective for 

compliance monitoring February 16, 

1999, unless a different effective date is 

specified in this section or by the State.

(2) The following documents are 

incorporated by reference. The Director 

of the Federal Register approves this 

incorporation by reference in 

accordance with 5 U.S.C. 552(a) and 1 

CFR part 51. Copies may be inspected 

at EPA’s Drinking Water Docket, 1301 

Constitution Avenue, NW., EPA West, 

Room B102, Washington, DC 20460, or 

at the Office of the Federal Register, 800 

North Capitol Street, NW., Suite 700, 

Washington, DC. EPA Method 552.1 is 

in Methods for the Determination of 

Organic Compounds in Drinking WaterSupplement II, USEPA, August 1992, 

EPA/600/R–92/129 (available through 

National Information Technical Service 

(NTIS), PB92–207703). EPA Methods 

502.2, 524.2, 551.1, and 552.2 are in 

Methods for the Determination of 

Organic Compounds in Drinking WaterSupplement III, USEPA, August 1995, 

EPA/600/R–95/131. (Available through 

NTIS, PB95–261616). EPA Method 

300.0 for chlorite and bromide is in 

Methods for the Determination of 

Inorganic Substances in Environmental 

Samples, USEPA, August 1993, EPA/

600/R–93/100 (available through NTIS, 

PB94–121811). EPA Methods 300.1 for 

chlorite, bromate, and bromide and 

321.8 for bromate are in Methods for the 

Determination of Organic and Inorganic 

Compounds in Drinking Water, Volume 

1, USEPA, August 2000, EPA 815–R–

00–014 (available through NTIS, 

PB2000–106981). EPA Method 317.0, 

Revision 2.0, ‘‘Determination of 

Inorganic Oxyhalide Disinfection ByProducts in Drinking Water Using Ion 

Chromotography with the Addition of a 

Postcolumn Reagent for Trace Bromate 

Analysis,’’ USEPA, July 2001, EPA 815–

B–01–001, EPA Method 326.0, Revision 

1.0, ‘‘Determination of Inorganic 

Oxyhalide Disinfection By-Products in 

Drinking Water Using Ion 

Chromatography Incorporating the 

Addition of a Suppressor Acidified 

Postcolumn Reagent for Trace Bromate 

Analysis,’’ USEPA, June 2002, EPA 815–

R–03–007, EPA Method 327.0, Revision 

1.0, ‘‘Determination of Chlorine Dioxide 

and Chlorite Ion in Drinking Water 

Using Lissamine Green B and 

Horseradish Peroxidase with Detection 

by Visible Spectrophotometry,’’ USEPA, 

July 2003, and EPA Method 552.3, 

Revision 1.0, ‘‘Determination of 

Haloacetic Acids and Dalapon in 

Drinking Water by Liquid-liquid 

Extraction, Derivatization, and Gas 

Chromatography with Electron Capture 

Detection,’’ USEPA, July 2003, can be

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49667

accessed and downloaded directly online at www.epa.gov/safewater/

methods/sourcalt.html. EPA Method 

415.3, Revision 1.0, ‘‘Determination of 

Total Organic Carbon and Specific UV 

Absorbance at 254 nm in Source Water 

and Drinking Water,’’ USEPA, June 

2003, is available from: Chemical 

Exposure Research Branch, 

Microbiological & Chemical Exposure 

Assessment Research Division, National 

Exposure Research Laboratory, U.S. 

Environmental Protection Agency, 

Cincinnati, OH 45268, Fax Number 

513–569–7757, Phone number: 513–

569–7586. Standard Methods 4500–Cl 

D, 4500–Cl E, 4500–Cl F, 4500–Cl G, 

4500–Cl H, 4500–Cl I, 4500–ClO2 E, 

6251 B, and 5910 B shall be followed in 

accordance with Standard Methods for 

the Examination of Water and 

Wastewater, 19th or 20th Editions or the 

On-Line Version, American Public 

Health Association, 1995, 1998, and 

2003, respectively. The cited methods 

published in any of these three editions 

may be used. Standard Method 4500–

ClO2 D shall be followed in accordance 

with Standard Methods for the 

Examination of Water and Wastewater, 

19th or 20th Editions, American Public 

Health Association, 1995 and 1998, 

respectively. Standard Methods 5310 B, 

5310 C, and 5310 D shall be followed in 

accordance with the Supplement to the 

19th Edition of Standard Methods for 

the Examination of Water and 

Wastewater, or the Standard Methods 

for the Examination of Water and 

Wastewater, 20th Edition, or the OnLine Version, American Public Health 

Association, 1995, 1998, and 2003, 

respectively. The cited methods 

published in any of these editions may 

be used. Copies may be obtained from 

the American Public Health 

Association, 1015 Fifteenth Street, NW., 

Washington, DC 20005. ASTM Method 

D 1253–86 shall be followed in 

accordance with the Annual Book of 

ASTM Standards, Volume 11.01, 

American Society for Testing and 

Materials, 1996 or any year containing 

the cited version of the method may be 

used. ASTM D 6581–00 shall be 

followed in accordance with the Annual 

Book of ASTM Standards, Volume 

11.01, American Society for Testing and 

Materials, 2001 or any year containing 

the cited version of the method may be 

used; copies may be obtained from the 

American Society for Testing and 

Materials, 100 Barr Harbor Drive, West 

Conshohoken, PA 19428–2959. 

(b) Disinfection byproducts. (1) 

Systems must measure disinfection 

byproducts by the methods (as modified 

by the footnotes) listed in the following 

table:

APPROVED METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING

Contaminant and methodology 1 EPA method Standard 

Method 2

ASTM 

Method 3

TTHM: 

P&T/GC/ElCD & PID ................................................................................ 502.2 4

P&T/GC/MS .............................................................................................. 524.2 

LLE/GC/ECD ............................................................................................. 551.1 

HAA5: 

LLE (diazomethane)/GC/ECD .................................................................. 6251 B5.

SPE (acidic methanol)/GC/ECD ............................................................... 552.1 5

LLE (acidic methanol)/GC/ECD ................................................................ 552.2, 552.3. 

Bromate: 

Ion chromatography .................................................................................. 300.1 ..................... D 6581–

00 

Ion chromatography & post column reaction ........................................... 317.0 Rev 2.0 6, 326.0 6

IC/ICP–MS ................................................................................................ 321.8 6, 7

Chlorite: 

Amperometric titration ............................................................................... 4500–C1O2

E8.

Spectrophotometry .................................................................................... 327.0 8. .

Ion chromatography .................................................................................. 300.0, 300.1, 317.0 Rev. 2.0, 326.0 ..................... D 6581–

00 

1P&T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID = photoionization detector; MS = mass spectrometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography; ICP-MS = inductively coupled plasma/mass spectrometer 2 219th or 20th editions or the On-Line Version of Standard Methods for the Examination of Water and Wastewater, 1995, 1998, and 2003, respectively, American Public Health Association; any of these editions may be used. 3Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01. 4 If TTHMs are the only analytes being measured in the sample, then a PID is not required. 

5The samples must be extracted within 14 days of sample collection. 

6 Ion chromatography & post column reaction or IC/ICP-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of 

reduced monitoring, as prescribed in § 141.132(b)(3)(ii). 7Samples must be preserved at the time of sampling with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days. 8Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as 

prescribed in § 141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in § 141.132(b)(2)(i)(B) and (b)(2)(ii). 

(2) Analysis under this section for 

disinfection byproducts must be 

conducted by laboratories that have 

received certification by EPA or the 

State, except as specified under 

paragraph (b)(3)of this section. To 

receive certification to conduct analyses 

for the DBP contaminants in §§ 141.64, 

141.135, and subparts U and V of this 

part, the laboratory must: 

(i) Analyze Performance Evaluation 

(PE) samples that are acceptable to EPA 

or the State at least once during each 

consecutive 12 month period by each 

method for which the laboratory desires 

certification. 

(ii) Achieve quantitative results on the 

PE sample analyses that are within the 

following acceptance limits which 

become effective [date 60 days after date 

of final rule publication] for purposes of 

certification:

49668 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

DBP 

Acceptance 

limits 

(percent) 

Comments 

TTHM: 

Chloroform .............................................................................

Bromodichloromethane ..........................................................

Dibromochloromethane ..........................................................

Bromoform .............................................................................

±20 

±20 

±20 

±20

Laboratory must meet all 4 individual THM acceptance limits in 

order to successfully pass a PE sample for TTHM. 

HAA5: 

Monochloroacetic Acid ...........................................................

Dichloroacetic Acid ................................................................

Trichloroacetic Acid ................................................................

Monobromacetic Acid ............................................................

Dibromoacetic Acid ................................................................

±40 

±40 

±40 

±40 

±40

Laboratory must meet the acceptance limits for 4 out of 5 of 

the HAAS compounds in order to successfully pass a PE 

sample for HAA5. 

Chlorite .......................................................................................... ±30 

Bromate ......................................................................................... ±30 

(iii) Report quantitative data for 

concentrations at least as low as the 

ones listed in the following table for all 

DBP samples analyzed for compliance 

with §§ 141.64, 141.135, 141.136, and 

subparts U and V of this part:

DBP 

Minimum reporting level 

(ug/L) 7

Comments 

TTHM 2: 

Chloroform ........................................................................... 1.0 

Bromodichloromethane ........................................................ 1.0 

Dibromochloromethane ....................................................... 1.0 

Bromoform ........................................................................... 1.0 

HAA5: 2

Monochloroacetic Acid ........................................................ 2.0 

Dichloroacetic Acid .............................................................. 1.0 

Trichloroacetic Acid ............................................................. 1.0 

Monobromoacetic Acid ........................................................ 1.0

Dibromoacetic Acid .............................................................. 1.0 

Chlorite ........................................................................................ 200.

Bromate ...................................................................................... 5.0 or 1.0 Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 

or 321.8 must meet a 1.0 μg/L MRL for bromate. 

1The calibration curve must encompass the minimum reporting level (MRL) concentration and the laboratory must verify the accuracy of the 

calibration curve at the lowest concentration for which quantitative data are reported by analyzing a calibration check standard at that concentration at the beginning of each batch of samples. The measured concentration for the check standard must be within ±50% of the expected value. 

Data may be reported for concentrations lower than the MRL as long as the precision and accuracy criteria are met by analyzing a standard at 

the lowest reporting limit chosen by the laboratory. 2When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a 

zero is used for any analytical result that is less than the MRL concentration for that DBP. 

(3) A party approved by EPA or the 

State must measure daily chlorite 

samples at the entrance to the 

distribution system. 

(c) * * *

(1) * * *

Methodology Standard 

method 

ASTM 

method EPA method 

Residual Measured 1

Free 

chlorine 

Combined 

chlorine 

Total 

chlorine 

Chlorine 

dioxide 

Amperometric Titration .......................... 4500–Cl D D 1253–86 X X X

Low Level Amperometric Titration ......... 4500–Cl E X

DPD Ferrous Titrimetric ......................... 4500–Cl F X X X 

DPD Colorimetric ................................... 4500–Cl G X X X 

Syringaldazine (FACTS) ........................ 4500–Cl X

Iodometric Electrode .............................. 4500–Cl X

DPD ....................................................... 4500–ClO2 X 

Amperometric Method II ........................ 4500–ClO2

E

X 

Lissamine Green Spectrophotometric ... 327.0 X 

1X indicates method is approved for measuring specified disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine or total chlorine may be measured for demonstrating compliance with the 

chloramine MRDL. 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49669

* * * * *

(d) * * *

(2) Bromide. EPA Methods 300.0, 

300.1, 317.0 Revision 2.0, 326.0, or 

ASTM D 6581–00. 

(3) Total Organic Carbon (TOC).

Standard Method 5310 B (HighTemperature Combustion Method) or 

Standard Method 5310 C (PersulfateUltraviolet or Heated-Persulfate 

Oxidation Method) or Standard Method 

5310 D (Wet-Oxidation Method) or EPA 

Method 415.3. Inorganic carbon must be 

removed from the samples prior to 

analysis. TOC samples may not be 

filtered prior to analysis. TOC samples 

must be acidified at the time of sample 

collection to achieve pH less than or 

equal to 2 with minimal addition of the 

acid specified in the method or by the 

instrument manufacturer. Acidified 

TOC samples must be analyzed within 

28 days. 

(4) * * *

(i) Dissolved Organic Carbon (DOC). 

Standard Method 5310 B (HighTemperature Combustion Method) or 

Standard Method 5310 C (PersulfateUltraviolet or Heated-Persulfate 

Oxidation Method) or Standard Method 

5310 D (Wet-Oxidation Method) or EPA 

Method 415.3. DOC samples must be 

filtered through the 0.45 μm porediameter filter as soon as practical after 

sampling, not to exceed 48 hours. After 

filtration, DOC samples must be 

acidified to achieve pH less than or 

equal to 2 with minimal addition of the 

acid specified in the method or by the 

instrument manufacturer. Acidified 

DOC samples must be analyzed within 

28 days. Inorganic carbon must be 

removed from the samples prior to 

analysis. Water passed through the filter 

prior to filtration of the sample must 

serve as the filtered blank. This filtered 

blank must be analyzed using 

procedures identical to those used for 

analysis of the samples and must meet 

the following criteria: DOC < 0.5 mg/L. 

(ii) Ultraviolet Absorption at 254 nm 

(UV254). Standard Method 5910 B 

(Ultraviolet Absorption Method) or EPA 

Method 415.3. UV absorption must be 

measured at 253.7 nm (may be rounded 

off to 254 nm). Prior to analysis, UV254

samples must be filtered through a 0.45 

μm pore-diameter filter. The pH of 

UV254 samples may not be adjusted. 

Samples must be analyzed as soon as 

practical after sampling, not to exceed 

48 hours.

* * * * *

(6) Magnesium. All methods allowed 

in § 141.23(k)(1) for measuring 

magnesium. 

9. Section 141.132 is amended by 

revising paragraphs (b)(3)(ii) and (e) to 

read as follows:

§ 141.132 Monitoring requirements.

* * * * *

(b) * * * 

(i) * * * 

(ii) Reduced monitoring. 

(A) Until [date three years from final 

rule publication], systems required to 

analyze for bromate may reduce 

monitoring from monthly to quarterly, if 

the system’s average source water 

bromide concentration is less than 0.05 

mg/L based on representative monthly 

bromide measurements for one year. 

The system may remain on reduced 

bromate monitoring until the running 

annual average source water bromide 

concentration, computed quarterly, is 

equal to or greater than 0.05 mg/L based 

on representative monthly 

measurements. If the running annual 

average source water bromide 

concentration is ≥0.05 mg/L, the system 

must resume routine monitoring 

required by paragraph (b)(3)(i) of this 

section. 

(B) Beginning [date three years from 

final rule publication], systems may no 

longer use the provisions of paragraph 

(b)(3)(ii)(A) of this section to qualify for 

reduced monitoring. A system required 

to analyze for bromate may reduce 

monitoring from monthly to quarterly, if 

the system’s running annual average 

bromate concentration is less than 

0.0025 mg/L based on monthly bromate 

measurements under paragraph (b)(3)(i) 

of this section for the most recent four 

quarters, with samples analyzed using 

Method 317.0 Revision 2.0, 325.0 or 

321.8. If a system has qualified for 

reduced bromate monitoring under 

paragraph (b)(3)(ii)(A) of this section, 

that system may remain on reduced 

monitoring as long as the running 

annual average of quarterly bromate 

samples does not exceed 0.0025 mg/L 

based on samples analyzed using 

Method 317.0 Revision 2.0, 325.0, or 

321.8. If the running annual average 

bromate concentration is >0.0025 mg/L, 

the system must resume routine 

monitoring required by paragraph 

(b)(3)(i) of this section.

* * * * *

(e) Monitoring requirements for source 

water TOC. In order to qualify for 

reduced monitoring for TTHM and 

HAA5 under paragraph (b)(1)(ii) of this 

section, subpart H systems not 

monitoring under the provisions of 

paragraph (d) of this section must take 

monthly TOC samples approximately 

every 30 days at a location prior to any 

treatment. In addition to meeting other 

criteria for reduced monitoring in 

paragraph (b)(1)(ii) of this section, the 

source water TOC running annual 

average must be ≤4.0 mg/L (based on the 

most recent four quarters of monitoring) 

on a continuing basis at each treatment 

plant to reduce or remain on reduced 

monitoring for TTHM and HAA5.

* * * * *

10. Section 141.134 is amended by 

revising paragraph (b) introductory text 

to read as follows:

§ 141.134 Reporting and recordkeeping 

requirements.

* * * * *

(b) Disinfection byproducts. In 

addition to reporting required under 

§ 141.136(e), systems must report the 

information specified in the following 

table:

* * * * *

11. Section 141.135 is amended by 

revising paragraph (a)(3)(ii) to read as 

follows:

§ 141.135 Treatment technique for control 

of disinfection byproduct (DBP) precursors. 

(a) * * * 

(3) * * * 

(ii) Softening that results in removing 

at least 10 mg/L of magnesium hardness 

(as CaCO3), measured monthly 

according to § 141.131(d)(6) and 

calculated quarterly as a running annual 

average.

* * * * *

12. Section 141.136 is added to 

subpart L to read as follows:

§ 141.136 Additional compliance 

requirements for Stage 2A. 

(a) Applicability. Any system that 

takes TTHM and HAA5 compliance 

samples under this subpart at more than 

one location in its distribution system is 

subject to additional MCL requirements 

beginning [date 3 years after publication 

of final rule] until the dates identified 

for compliance with subpart V in 

§ 141.620(c). Any system that takes 

samples at more than one location must 

calculate a locational running annual 

average (LRAA) for each sampling point 

and comply with the MCLs of 0.120 mg/

L for TTHM and 0.100 mg/L for HAA5 

listed in § 141.64(b)(2), except as 

provided for under paragraph (c) of this 

section. 

(b) Compliance. (1) Systems must 

calculate a locational running annual 

average each quarter for each 

monitoring location at which they took 

TTHM and HAA5 samples under their 

monitoring plan developed under 

§ 141.132(f) by averaging the results of 

TTHM or HAA5 monitoring at that 

sample location during the four most 

recent quarters. 

(2) Systems required to conduct 

quarterly monitoring under this subpart 

must begin to make compliance 

calculations under paragraph (b) of this

49670 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

section at the end of the fourth calendar 

quarter that follows the compliance date 

in paragraph (a) of this section and at 

the end of each subsequent quarter. 

Systems required to conduct monitoring 

at a frequency that is less than quarterly 

under this subpart must make 

compliance calculations under 

paragraph (b) of this section beginning 

with the first compliance sample taken 

after the compliance date in paragraph 

(a) of this section. 

(3) Failure to monitor will be treated 

as a monitoring violation for each 

quarter that a monitoring result would 

be used in a locational running annual 

average compliance calculation. 

(c) Consecutive systems. A 

consecutive system must comply with 

the TTHM and HAA5 MCLs in 

§ 141.64(b)(2) at each monitoring 

location in its distribution system 

identified in its monitoring plan 

developed under § 141.132(f). 

(d) Reporting. Systems must submit 

the compliance calculations and 

locational running annual averages 

under this section as part of the reports 

required under § 141.134.

Subpart O—[Amended] 

13. Section 141.151 is amended by 

revising paragraph (d) to read as 

follows:

§ 141.151 Purpose and applicability of this 

subpart.

* * * * *

(d) For the purpose of this subpart, 

detected means: At or above the levels 

prescribed by § 141.23(a)(4) for 

inorganic contaminants, at or above the 

levels prescribed by § 141.24(f)(7) for 

the contaminants listed in § 141.61(a), at 

or above the levels prescribed by 

§ 141.24(h)(18) for the contaminants 

listed in § 141.61(c), at or above the 

levels prescribed by § 141.131(b)(2)(iii) 

for the contaminants or contaminant 

groups listed in § 141.64 and 

§ 141.153(d)(iv), and at or above the 

levels prescribed by § 141.25(c) for 

radioactive contaminants.

* * * * *

14. Section 141.153 is amended by 

revising paragraphs (d)(4)(iv)(B) and 

(d)(4)(iv)(C) to read as follows:

§ 141.153 Content of the reports.

* * * * *

(d) * * * 

(4) * * * 

(iv) * * * 

(B) When compliance with the MCL is 

determined by calculating a running 

annual average of all samples taken at 

a sampling point: the highest average of 

any of the sampling points and the 

range of all sampling points expressed 

in the same units as the MCL. For the 

MCLs for TTHM and HAA5 in 

§ 141.64(b)(2) and (3), systems must 

include the highest locational running 

annual average for TTHM and HAA5 

and the range of individual sample 

results for all sampling points expressed 

in the same units as the MCL. If more 

than one site exceeds the MCL, the 

system must include the locational 

running annual averages for all sites that 

exceed the MCL. 

(C) When compliance with the MCL is 

determined on a system-wide basis by 

calculating a running annual average of 

all samples at all sampling points: the 

average and range of detection 

expressed in the same units as the MCL. 

The system is not required to include 

the range of individual sample results 

for the IDSE conducted under subpart U 

of this part.

* * * * *

Subpart Q—[Amended] 

15. In Appendix A, the table is 

amended by revising entries 1.G.1 and 

1.G.2, and endnotes 12 and 20, to read 

as follows:

APPENDIX A TO SUBPART Q OF PART 141.—NPDWR VIOLATIONS AND OTHER SITUATIONS REQUIRING PUBLIC NOTICE 1

Contaminant 

MCL/MRDL/TT violations2 Monitoring and testing procedure violations 

Tier of public notice 

required 

Citation 

Tier of public notice 

required 

Citation 

I. Violations of National Primary Drinking Water Regulations (NPDWR):3

* * * * * * * 

G. Disinfection Byproducts, * * * 

1. Total trihalomethanes (TTHM) ....................................... 2 141.1212, 

141.64(b)20

3 141.3012, 

141.132(a)–(b)20, 

141.620–.630 

2. Haloacetic acids (HAA5) ................................................ 2 141.64(b)20 3 141.132(a)–(b)20, 

141.620–.630 

* * * * *

Appendix A—Endnotes 

12. §§ 141.12 and 141.30 will no longer 

apply after December 31, 2003.

* * * * *

20. §§ 141.64(b)(1) and 141.132(a)-(b) apply 

until §§ 141.64(b)(3) and 141.620–.630 take 

effect under the schedule in § 141.620(c). 

§ 141.64(b)(2) takes effect on [date three years 

following final rule publication] and remains 

in effect until the effective dates for subpart 

V of this part compliance in the table in 

§ 141.620(c).

* * * * *

16. In Appendix B the table is 

amended by revising entries H.79, H.80, 

and endnote 17, and adding endnote 23, 

to read as follows:

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49671

APPENDIX B TO SUBPART Q OF PART 141—STANDARD HEALTH EFFECTS LANGUAGE FOR PUBLIC NOTIFICATION

Contaminant MCLG1 mg/

L MCL2 mg/L 

Standard health 

effects language 

for public 

notification 

* * * * * * * 

H. Disinfection Byproducts (DBPs), * * * 17: 

79. Total trihalomethanes (TTHLM) .................................................................. N/A 0.10/0.120/0.080 18, 19, 23 * * * 

80. Haloacetic acids (HAA5). ............................................................................ N/A 0.060/0.10020, 23 * * * 

* * * * *

Appendix B—Endnotes

* * * * *

17. Surface water systems and ground 

water systems under the direct influence of 

surface water are regulated under subpart H 

of 40 CFR 141. Subpart H community and 

non-transient non-community systems 

serving ≥10,000 must comply with subpart L 

DBP MCLs and disinfectant maximum 

residual disinfectant levels (MRDLs) 

beginning January 1, 2002. All other 

community and non-transient noncommunity systems must comply with 

subpart L DBP MCLs and disinfectant MRDLs 

beginning January 1, 2004. Subpart H 

transient non-community systems serving 

≥10,000 that use chlorine dioxide as a 

disinfectant or oxidant must comply with the 

chlorine dioxide MRDL beginning January 1, 

2002. All other transient non-community 

systems that use chlorine dioxide as a 

disinfectant or oxidant must comply with the 

chlorine dioxide MRDL beginning January 1, 

2004.

* * * * *

23. Community and non-transient noncommunity systems must comply with 

TTHM and HAA5 MCLs of 0.120 mg/L and 

0.100 mg/L, respectively (with compliance 

calculated as a locational running annual 

average) beginning [date three years 

following publication of final rule] until they 

are required to comply with subpart V TTHM 

and HAA5 MCLs of 0.080 mg/L and 0.060 

mg/L, respectively (with compliance 

calculated as a locational running annual 

average). Community and non-transient noncommunity systems serving ≥10,000 must 

comply with subpart V TTHM and HAA5 

MCLs (with compliance calculated as a 

locational running annual average) beginning 

[date six years following publication of final 

rule]. Community and non-transient noncommunity systems serving <10,000 must 

comply with subpart V TTHM and HAA5 

MCLs (with compliance calculated as a 

locational running annual average) beginning 

[date 90 months following publication of 

final rule].

* * * * *

17. Part 141 is amended by adding 

new subpart U to read as follows:

Subpart U—Initial Distribution System 

Evaluations 

Sec.

141.600 General requirements. 

141.601 Initial Distribution System 

Evaluation (IDSE) requirements. 

141.602 IDSE monitoring. 

141.603 Alternatives other than IDSE 

monitoring. 

141.604 IDSE reports. 

141.605 Subpart V monitoring location 

recommendations to the State.

Subpart U—Initial Distribution System 

Evaluations

§ 141.600 General requirements. 

(a) The requirements of subpart U 

constitute national primary drinking 

water regulations. The regulations in 

this subpart establish monitoring and 

other requirements for identifying 

compliance monitoring locations to be 

used for determining compliance with 

maximum contaminant levels for total 

trihalomethanes (TTHM) and haloacetic 

acids (five)(HAA5) in subpart V through 

the use of an Initial Distribution System 

Evaluation (IDSE). IDSEs are studies, 

used in conjunction with subpart L 

compliance monitoring, to identify and 

select subpart V compliance monitoring 

sites that represent high TTHM and 

HAA5 levels throughout the distribution 

system. The studies will be based on 

system-specific monitoring as provided 

in § 141.602. As an alternative, you may 

use other system-specific data that 

provide equivalent or better information 

on site selection for monitoring under 

subpart V as provided for in 

§ 141.603(a). 

(b) Applicability. You are subject to 

these requirements if your system is a 

community water system that adds a 

primary or residual disinfectant other 

than ultraviolet light or delivers water 

that has been treated with a primary or 

residual disinfectant other than 

ultraviolet light or if your system is a 

nontransient noncommunity water 

system that serves at least 10,000 people 

and adds a primary or residual 

disinfectant other than ultraviolet light 

or delivers water that has been treated 

with a primary or residual disinfectant 

other than ultraviolet light. You must 

conduct an Initial Distribution System 

Evaluation (IDSE), unless you meet the 

40/30 certification criteria in 

§ 141.603(b) or the State has granted a 

very small system waiver for the IDSE 

or you meet the criteria defined by the 

State for a very small system waiver 

under § 141.603(c). If you have a very 

small system waiver for the IDSE under 

§ 141.603(c), you are not required to 

submit an IDSE report. All other 

systems must submit an IDSE report, 

even if you meet the 40/30 certification 

criteria in § 141.603(c). 

(c) Schedule. You must comply with 

the Initial Distribution System 

Evaluation (IDSE) on the schedule in the 

following table, based on your system 

type.

If you are this type of system You must submit your IDSE report to the state by 1

(1) Subpart H serving ≥10,000 ................................................. [date 24 mos. following publication of final rule] 

(2) Subpart H serving <10,000 ................................................. [date 24 mos. following publication of final rule] 2

(3) Ground water serving ≥10,000 ........................................... [date 24 mos. following publication of final rule] 

(4) Ground water serving <10,000 ........................................... [date 24 mos. following publication of final rule] 2

(5) Consecutive system ............................................................ at the same time as the system with the earliest compliance date in the combined distribution system 3

1Systems that meet the 40/30 certification criteria in § 141.603(b) are encouraged to submit their IDSE report as soon as the certification criteria are met. 2You must comply by [date 24 mos. following publication of final rule] if you are a wholesale system and any system in the combined distribution system serves at least 10,000 people. You must comply by [date 48 mos. following publication of final rule] if no system in the combined distribution system serves at least 10,000 people. 

49672 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

3You must comply by [date 24 mos. following publication of final rule] if any system in the combined distribution system serves at least 10,000 

people. You must comply by [date 48 mos. following publication of final rule] if no system in the combined distribution system serves at least 

10,000 people. 

(d) Violations. You must comply with 

specific monitoring and reporting 

requirements. You must prepare for, 

conduct, analyze, and submit your IDSE 

report no later than the date specified in 

§ 141.600(c). Failure to conduct a 

required IDSE or to submit a required 

IDSE report by the date specified in 

paragraph (c) of this section is a 

monitoring violation. If you do not 

submit your IDSE report to your State, 

or if you submit the report after the 

specified date, you must comply with 

any additional State-specified 

requirements, which may include 

conducting another IDSE.

§ 141.601 Initial Distribution System 

Evaluation (IDSE) requirements. 

(a) You must conduct an IDSE that 

meets the requirements in § 141.602 or 

§ 141.603(a) or meet the 40/30 

certification criteria in § 141.603(b) or 

have received a very small system 

waiver for the IDSE from the State under 

§ 141.603(c). If you do not take the full 

complement of TTHM and HAA5 

compliance samples required of a 

system with your population and source 

water under subpart L, but are required 

to conduct an IDSE under this subpart, 

you are not eligible for either the 40/30 

certification in § 141.603(b) or the very 

small system waiver in § 141.603(c) and 

must conduct an IDSE that meets the 

requirements in § 141.602 or 

§ 141.603(a). 

(b) You may use any alternative listed 

in the table below for which you 

qualify.

IDSE ALTERNATIVES

Alternatives Eligibility Regulatory reference 

(1) Monitoring ...................... All systems required to conduct an IDSE ..................................................................... § 141.602 

(2) System-specific study .... All systems required to conduct an IDSE ..................................................................... § 141.603(a) 

(3) 40/30 certification .......... Any system with all TTHM compliance samples ≤0.040 mg/L and all HAA5 compliance samples ≤0.030 mg/L during the period specified in § 141.603(b).§ 141.603(b) 

(4) Very small system waiver.Any system serving <500 for which the State has granted a waiver ........................... § 141.603(c) 

(c) IDSE results will not be used for 

the purpose of determining compliance 

with MCLs in § 141.64. 

(d) Additional provisions:

(1) You may consider multiple wells 

drawing water from a single aquifer as 

one treatment plant for determining the 

minimum number of TTHM and HAA5 

samples required, with State approval in 

accordance with criteria developed 

under § 142.16(h)(5) of this chapter. 

State approvals made under 

§ 141.132(a)(2) to treat multiple wells 

drawing water from a single aquifer as 

one treatment plant remain in effect 

unless withdrawn by the State. 

(2) If you are a consecutive system, 

you must comply with the IDSE 

requirements in this subpart based on 

whether you buy some or all of your 

water from another PWS during 2004 for 

systems with an IDSE report due [date 

24 months after publication of final 

rule] or during 2006 for systems with an 

IDSE report due [date 48 months after 

publication of final rule]. A consecutive 

system that buys some, but not all, of its 

finished water during the period 

identified in this paragraph must treat 

each consecutive system entry point 

from a wholesale system as a treatment 

plant for the consecutive system for the 

purpose of determining monitoring 

requirements of this subpart if water is 

delivered from the wholesale system to 

the consecutive system for at least 60 

consecutive days through any of the 

consecutive system entry points. A 

consecutive system that buys all its 

finished water during the period 

identified in this paragraph must 

monitor based on population and source 

water for the purpose of determining 

monitoring requirements of this subpart. 

(i) You may request that the State 

allow multiple consecutive system entry 

points from a single wholesale system to 

a single consecutive system to be 

considered one treatment plant. 

(ii) In the request to the State for 

approval of multiple consecutive system 

entry points to be considered one 

treatment plant, you must demonstrate 

that factors such as relative locations of 

entry points, detention times, sources, 

and the presence of treatment (such as 

corrosion control or booster 

disinfection) will have a minimal 

differential effect on TTHM and HAA5 

formation associated with individual 

entry points.

§ 141.602 IDSE monitoring. 

(a) You must conduct IDSE 

monitoring for each treatment plant as 

indicated in the table in this paragraph. 

You must collect dual sample sets at 

each monitoring location. One sample 

in the set must be analyzed for TTHM. 

The other sample in the set must be 

analyzed for HAA5. If approved by the 

State under the provisions of 

§ 141.601(d)(1), you may consider 

multiple wells drawing water from the 

same aquifer to be one treatment plant 

for the purpose of determining 

monitoring requirements. You must 

conduct one monitoring period during 

the peak historical month for TTHM 

levels or HAA5 levels or the month of 

warmest water temperature. You must 

review available compliance, study, or 

operational data to determine the peak 

historical month for TTHM or HAA5 

levels or warmest water temperature.

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49673

If you are this type of system Then you must monitor At these locations for each treatment plant 1,2

(1) Subpart H serving ≥10,000 Approximately every 60 days for one year (six 

monitoring periods).

Eight dual sample sets per monitoring period at locations 

other than subpart L TTHM/HAA5 monitoring locations 

based on conditions: 

If CHLORINE is used as residual disinfectant: one near distribution system entry point, two at average residence time, 

five at points representative of highest expected TTHM 

(three sites) and HAA5 concentration (two sites). 

If CHLORAMINE is used as residual disinfectant for any part 

of the year: two near distribution system entry point, two at 

average residence time, four at points representative of 

highest expected TTHM (two sites) and HAA5 concentration (two sites). 

(2) Subpart H serving 500-

9,999.

Approximately every 90 days for one year 

(four monitoring periods).

Two dual sample sets per monitoring period at locations other 

than the for one year subpart L TTHM/HAA5 monitoring location; one each representative of expected high periods) 

TTHM level and HAA5 level. 

(3) Subpart H serving <500 ...... Approximately every 180 days for one year 

(two monitoring periods).

Two dual sample sets per monitoring period at locations other 

than the subpart L TTHM/HAA5 monitoring location; one 

each representative of expected high periods) TTHM level 

and HAA5 level. 

(4) Ground water serving 

≥10,000.

Approximately every 90 days for one year 

(four monitoring periods).

Two dual sample sets per monitoring period at locations other 

than the subpart L TTHM/HAA5 monitoring location; one 

each representative of expected high periods) TTHM level 

and HAA5 level. 

(5) Ground water serving < 

10,000.

Approximately every 180 days for one year 

(two monitoring periods).

Two dual sample sets per monitoring period at locations other 

than the subpart L TTHM/HAA5 monitoring location; one 

each representative of expected high periods) TTHM level 

and HAA5 level. 

(6) Consecutive system ............ At a frequency based on source water and 

your population 3.

—For a consecutive system that buys all its finished water, 

number of samples and locations as specified in paragraph 

(b) of this section. 

—For a consecutive system that buys some, but not all, of its 

finished water, serves ≥10,000, and receives water from a 

subpart H system: at IDSE locations required of a subpart 

H system serving ≥10,000. 

—For a consecutive system that does not meet any other criteria in this paragraph: two dual sample sets per monitoring 

period at locations other than the subpart L TTHM/HAA5 

compliance monitoring location; one each representative of 

expected high TTHM levels and HAA5 levels. 

1 Including treatment plants for consecutive system entry points that operate for at least 60 consecutive days. 

2The State may require additional monitoring. 

3You must monitor at the frequency required of a subpart H system with your population if you deliver any water required to be treated under 

subpart H. You must monitor at the frequency required of a ground water system with your population if you deliver no water required to be treated under subpart H. 

(b) IDSE monitoring for consecutive 

systems that buy all their water.

IDSE MONITORING LOCATIONS FOR CONSECUTIVE SYSTEMS THAT BUY ALL THEIR WATER

Population category 

Number of 

dual sample 

set locations 

per monitoring period 

Distribution system dual sample set locations 1

Near entry 

points 2

Average 

residence 

time 

Highest 

TTHM 

locations 

Highest 

HAA5 

locations 

Subpart H Consecutive Systems that buy all their water

<500 3 ............................................................................................................. 2 1 1 

500 to 4,999 4 ................................................................................................ 2 1 1 

5,000 to 9,999 4 ............................................................................................. 4 1 2 1 

10,000 to 24,999 5 ......................................................................................... 8 1 2 3 2 

25,000 to 49,999 5 ......................................................................................... 12 2 3 4 3 

50,000 to 99,999 5 ......................................................................................... 16 3 4 5 4 

100,000 to 499,999 5 ..................................................................................... 24 4 6 8 6 

500,000 to 1,499,999 5 .................................................................................. 32 6 8 10 8 

1,500,000 to 4,999,999 5 ............................................................................... 40 8 10 12 10 

>=5,000,000 5 ................................................................................................. 48 10 12 14 12 

49674 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

IDSE MONITORING LOCATIONS FOR CONSECUTIVE SYSTEMS THAT BUY ALL THEIR WATER—Continued

Population category 

Number of 

dual sample 

set locations 

per monitoring period 

Distribution system dual sample set locations 1

Near entry 

points 2

Average 

residence 

time 

Highest 

TTHM 

locations 

Highest 

HAA5 

locations 

Ground Water Consecutive Systems that buy all their water

<500 3 ............................................................................................................. 2 1 1 

500 to 9,999 4 ................................................................................................ 2 1 1 

10,000 to 99,999 4 ......................................................................................... 6 1 1 2 2 

100,000 to 499,999 4 ..................................................................................... 8 1 1 3 3 

≥500,000 4 ...................................................................................................... 12 2 2 4 4 

1Sampling locations to be distributed through distribution system. You may not use subpart L compliance monitoring locations as IDSE sample 

sites. You must collect a dual sample set at each sample location. 2 If the actual number of entry points to the distribution system is fewer than the specified number of ‘‘near entry point’’ sampling sites, take additional samples equally at highest TTHM and HAA5 locations. If there is an odd extra location number, take the odd sample at highest TTHM location. If the actual number of entry points to the distribution system is more than the specified number of sampling locations, take samples first 

at subpart H entry points to the distribution system having the highest water flows and then at ground water entry points to the distribution system having the highest water flows. 3You must conduct monitoring during two monitoring periods approximately 180 days apart. 

4You must conduct monitoring during four monitoring periods approximately 90 days apart. 

5You must conduct monitoring during six monitoring periods approximately 60 days apart. 

(c) You must prepare an IDSE 

monitoring plan prior to starting IDSE 

monitoring and implement that plan. In 

the plan, you must identify specific 

monitoring locations and dates that 

meet the criteria in paragraphs (a) and 

(b) of this section, as applicable.

§ 141.603 Alternatives other than IDSE 

monitoring. 

In lieu of IDSE monitoring under 

§ 141.602, you may use one of the 

alternatives identified in paragraphs (a) 

through (c) of this section for which you 

qualify to comply with this subpart. 

(a) System-specific study. You may 

perform an IDSE study based on systemspecific monitoring or system-specific 

data if such a study identifies equivalent 

or superior monitoring sites 

representing high TTHM and HAA5 

levels as would be identified by IDSE 

monitoring under § 141.602. You must 

submit an IDSE report that complies 

with § 141.604. 

(b) 40/30 certification. In order to 

qualify for the 40/30 certification, you 

must not have had any TTHM or HAA5 

monitoring violations during the 

periods specified in paragraphs (b)(1) 

through (b)(3) of this section. 

(1) You are not required to comply 

with § 141.602 or paragraph (a) of this 

section if you certify to your State that 

all compliance samples under subpart L 

in 2002 and 2003 (for subpart H systems 

serving ≥10,000 people) or in 2004 and 

2005 (for systems serving <10,000 

people that are not required to submit 

an IDSE report by [date 24 months 

following publication of final rule]) 

were ≤0.040 mg/L for TTHM and ≤0.030 

mg/L for HAA5. 

(2) If you are a ground water system 

serving ≥10,000 people, you are not 

required to comply with § 141.602 or 

paragraph (a) of this section if you 

certify to your State that all TTHM 

samples taken under § 141.30 in 2003 

are ≤0.040 mg/L and that all TTHM and 

HAA5 compliance samples taken under 

subpart L during 2004 are ≤0.040 mg/L 

and ≤0.030 mg/L, respectively. 

(3) If you are a consecutive system 

serving <10,000 required to submit an 

IDSE report by [date 24 months 

following publication of final rule], you 

are not required to comply with 

§ 141.602 or paragraph (a) of this section 

if you certify to your State that all 

TTHM and HAA5 compliance samples 

taken under subpart L during 2004 are 

≤0.040 mg/L and ≤0.030 mg/L, 

respectively. 

(4) You must submit an IDSE report 

that complies with § 141.604 and 

contains the required certification. 

(c) Very small system waiver. If you 

serve fewer than 500 people, the State 

may waive IDSE monitoring if the State 

determines that the TTHM and HAA5 

monitoring site for each plant under 

§ 141.132 is sufficient to represent both 

the highest TTHM and the highest 

HAA5 concentration in your 

distribution system. If your IDSE 

monitoring is waived, you are not 

required to submit an IDSE report. You 

must monitor under subpart V during 

the same month and at the same 

location as used for compliance 

sampling in subpart L.

§ 141.604 IDSE reports. 

You must submit your IDSE report to 

the State according to the schedule in 

§ 141.600(c). 

(a) If you complied by meeting the 

provisions of §§ 141.602 or 141.603(a), 

your IDSE report must include the 

elements required in paragraphs (a)(1) 

through (a)(3) of this section. 

(1) Your report must include all 

TTHM and HAA5 analytical results 

from subpart L compliance monitoring 

conducted during the period of the IDSE 

presented in a tabular or spreadsheet 

format acceptable to the State. Your 

report must also include a schematic of 

your distribution system, with results, 

location, and date of all IDSE 

monitoring, system-specific study 

monitoring, and subpart L compliance 

samples noted. 

(2) If you conducted IDSE monitoring 

under § 141.602, your report must 

include all IDSE TTHM and HAA5 

analytical results presented in a tabular 

or spreadsheet format acceptable to the 

State. Your report must also include all 

additional data you relied on to justify 

IDSE monitoring site selection, plus 

your original monitoring plan 

developed under § 141.602(c) and an 

explanation of any deviations from that 

plan. 

(3) If you used the system-specific 

study alternative in § 141.603(a), your 

report must include the basis (studies, 

reports, data, analytical results, 

modeling) by which you determined 

that the recommended subpart V 

monitoring sites representing high 

TTHM and HAA5 levels are comparable 

or superior to those that would 

otherwise have been identified by IDSE

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49675

monitoring under § 141.602. Your report 

must also include an analysis that 

demonstrates that your system-specific 

study characterized expected TTHM 

and HAA5 levels throughout your entire 

distribution system. 

(b) If you meet the 40/30 certification 

criteria in § 141.603(b), your IDSE report 

must include all TTHM and HAA5 

analytical results from compliance 

monitoring used to qualify for the 40/30 

certification and a schematic of your 

distribution system (with results, 

location, and date of all compliance 

samples noted). You must also include 

results of those compliance samples 

taken after the period used to qualify for 

the 40/30 certification for State review. 

(c) Your IDSE report must include 

your recommendations and justification 

for where and during what month(s) 

TTHM and HAA5 monitoring for 

Subpart V should be conducted. You 

must base your recommendations on the 

criteria in § 141.605. Your IDSE report 

must also include the population 

served; system type (subpart H or 

ground water); whether your system is 

a consecutive system; and, if you 

conducted plant-based monitoring, the 

number of treatment plants and 

consecutive system entry points. 

(d) Recordkeeping. You must retain a 

complete copy of your IDSE report 

submitted under § 141.604 for 10 years 

after the date that you submitted your 

IDSE report. If the State modifies the 

monitoring requirements that you 

recommended in your IDSE report or if 

the State approves alternative 

monitoring sites, you must keep a copy 

of the State’s notification on file for 10 

years after the date of the State’s 

notification. You must make the IDSE 

report and any State notification 

available for review by the State or the 

public.

§ 141.605 Subpart V monitoring location 

recommendations to the State. 

(a) Subpart H systems serving at least 

10,000 people. If you are a system 

required to take four dual sample sets 

per treatment plant per quarter under 

routine monitoring under § 141.621, you 

must base your recommendations on the 

locations in the distribution system 

where you expect to find the highest 

TTHM and HAA5 LRAAs. In 

determining the highest LRAA, you 

must evaluate both subpart L 

compliance data and IDSE data. For 

each plant, you must recommend 

locations with: 

(1) The two highest TTHM locational 

running annual averages; 

(2) The highest HAA5 locational 

running annual average; and 

(3) An existing subpart L compliance 

monitoring location identified in the 

§ 141.132(f) monitoring plan that is the 

location of either the highest TTHM or 

HAA5 LRAA among the three 

compliance monitoring locations 

representative of average residence time 

(by calculating an LRAA for each 

compliance monitoring location using 

the compliance monitoring results 

collected during the period of the IDSE). 

(4) You may recommend locations 

other than those in paragraphs (a)(1) 

through (3) of this section if you include 

a rationale for selecting other locations. 

If the State approves, you must monitor 

at these locations to determine 

compliance under subpart V.

(5) If any of the criteria in this 

paragraph (a) of this section would 

cause fewer than four locations per 

treatment plant to be recommended, you 

must identify an additional location(s) 

with the next highest HAA5 LRAA. 

(b) All groundwater systems and 

subpart H systems serving fewer than 

10,000 people. If you are a system 

required to take two dual sample sets 

per treatment plant per quarter or per 

year or one TTHM and one HAA5 

sample per plant per year for routine 

monitoring under § 141.621, you must 

select the locations with the highest 

TTHM locational running annual 

average and highest HAA5 locational 

running annual average, unless you 

include a rationale for selecting other 

locations. If the State approves, you 

must monitor at these other locations to 

determine compliance under subpart V. 

If any of the criteria in this paragraph 

would cause only one location per 

treatment plant to be recommended, you 

must identify an additional location 

with the next highest HAA5 LRAA or 

request that you be allowed to monitor 

only at that location. 

(c) Systems that qualify for the 40/30 

certification. If you use the 40/30 

certification in § 141.603(b), you may 

use either subpart L compliance 

monitoring locations or you may 

identify monitoring locations for 

Subpart V that are different from those 

for subpart L. You must include a 

rationale for changing existing subpart L 

locations, choosing locations with a 

long residence time and a detectable 

residual. If you choose monitoring 

locations other than those in subpart L 

as subpart V compliance monitoring 

locations, you must retain the subpart L 

locations with the highest TTHM and 

HAA5 LRAAs. If any of the criteria in 

this paragraph would cause only one 

location per treatment plant to be 

recommended, you must identify an 

additional location with the next 

highest HAA5 LRAA or request that you 

be allowed to monitor only at that 

location. If you are required to monitor 

at more locations under subpart V of 

this part than under subpart L of this 

part, you must identify additional 

locations with a long residence time and 

a detectable residual. 

(d) Consecutive systems that buy 

some, but not all, of their finished water.

Your recommendations must comply 

with §§ 141.601(d) and 141.605 (a) 

through (c). 

(e) Consecutive systems that buy all 

their finished water.

(1) You must select the number of 

monitoring locations specified in the 

following tables.

SUBPART V.—SAMPLE FREQUENCY FOR TTHM/HAA5 (AS DUAL SAMPLE SETS) FOR CONSECUTIVE SYSTEMS THAT BUY

ALL THEIR WATER

Population Number of samples 

Subpart H Consecutive Systems That Buy All Their Water

<500 .................................... 1 TTHM and 1 HAA5 sample per year at different locations and time if the highest TTHM and HAA5 occurred at 

different locations and/or time or 1 dual sample set per year if the highest TTHM and HAA5 occurred at the 

same location and time of year, taken during the peak historical month for DBP concentrations or (if unknown) 

month of warmest water temperature. 

500 to 4,999 ....................... 1 TTHM and 1 HAA5 sample per quarter at different locations if the highest TTHM and HAA5 occurred at different 

locations or 1 dual sample set per quarter if the highest TTHM and HAA5 occurred at the same location. 

5,000 to 9,999 .................... 2 dual sample sets per quarter. 

10,000 to 24,999 ................ 4 dual sample sets per quarter. 

25,000 to 49,999 ................ 6 dual sample sets per quarter. 

50,000 to 99,999 ................ 8 dual sample sets per quarter. 

49676 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

SUBPART V.—SAMPLE FREQUENCY FOR TTHM/HAA5 (AS DUAL SAMPLE SETS) FOR CONSECUTIVE SYSTEMS THAT BUY

ALL THEIR WATER—Continued

Population Number of samples 

100,000 to 499,999 ............ 12 dual sample sets per quarter. 

500,000 to 1,499,999 ......... 16 dual sample sets per quarter. 

1,500,000 to 4,999,999 ...... 20 dual sample sets per quarter. 

>=5,000,000 ....................... 24 dual sample sets per quarter. 

Ground Water Consecutive Systems That Buy All Their Water

<500 .................................... 1 TTHM and 1 HAA5 sample per year at different locations and time if the highest TTHM and HAA5 occurred at 

different locations and/or time or 1 dual sample set per year if the highest TTHM and HAA5 occurred at the 

same location and time of year, taken during the peak historical month for DBP concentrations, or, if unknown, 

during month of warmest water temperature. 

500 to 9,999 ....................... 2 dual sample sets per year. Must be taken during the peak historical month for DBP concentrations. 

10,000 to 99,999 ................ 4 dual sample sets per quarter. 

100,000 to 499,999 ............ 6 dual sample sets per quarter. 

≥500,000 ............................. 8 dual sample sets per quarter. 

(2) You must select Subpart V 

monitoring locations based on subpart L 

compliance monitoring results collected 

during the period of the IDSE and IDSE 

monitoring results. You must follow the 

protocol in paragraphs (e)(2)(i) through 

(iv) of this section, unless you provide 

a rationale for recommending different 

locations. If required to monitor at more 

than four locations, you must repeat the 

protocol as necessary, alternating 

between sites with the highest HAA5 

LRAA and the highest TTHM LRAA not 

previously selected as a subpart V 

monitoring location for choosing 

locations under paragraph (e)(2)(iii) of 

this section. 

(i) Location with the highest TTHM 

LRAA not previously selected as a 

subpart V monitoring location. 

(ii) Location with the highest HAA5 

LRAA not previously selected as a 

subpart V monitoring location. 

(iii) Existing subpart L average 

residence time compliance monitoring 

location. 

(iv) Location with the highest TTHM 

LRAA not previously selected as a 

subpart V monitoring location. 

(3) You may recommend locations 

other than those in paragraph (e)(2) of 

this section if you include a rationale for 

selecting other locations. If the State 

approves, you must monitor at these 

locations to determine compliance 

under subpart V. 

(4) If you used the 40/30 certification 

in § 141.603(b) and do not have 

sufficient subpart L monitoring 

locations to identify the required 

number of Subpart V compliance 

monitoring locations, you must identify 

additional locations by selecting a site 

representative of maximum residence 

time and then a site representative of 

average residence time and repeating 

until the required number of 

compliance monitoring locations have 

been identified. 

(f) You must schedule samples during 

the peak historical month for TTHM and 

HAA5 concentration, unless the State 

approves another month. Once you have 

identified the peak historical month, 

and if you are required to conduct 

routine monitoring at least quarterly, 

you must schedule subpart V 

compliance monitoring at a regular 

frequency of approximately every 90 

days or fewer. 

18. Part 141 is amended by adding 

new subpart V to read as follows:

Subpart V—Stage 2B Disinfection 

Byproducts Requirements 

Sec. 

141.620 General requirements. 

141.621 Routine monitoring.

141.622 Subpart V monitoring plan. 

141.623 Reduced monitoring. 

141.624 Additional requirements for 

consecutive systems. 

141.625 Conditions requiring increased 

monitoring. 

141.626 Significant excursions. 

141.627 Requirements for remaining on 

reduced TTHM and HAA5 monitoring 

based on subpart L results. 

141.628 Requirements for remaining on 

increased TTHM and HAA5 monitoring 

based on subpart L results. 

141.629 [Reserved] 

141.630 Reporting and recordkeeping 

requirements.

Subpart V—Stage 2B Disinfection 

Byproducts Requirements

§ 141.620 General requirements. 

(a) The requirements of subpart V 

constitute national primary drinking 

water regulations. These regulations 

establish requirements for control of 

certain disinfection byproducts that 

supercede some requirements in subpart 

L and that are in addition to other 

requirements that are currently required 

under subpart L of this part. The 

regulations in this subpart establish 

monitoring and other requirements for 

achieving compliance with maximum 

contaminant levels for total 

trihalomethanes (TTHM) and haloacetic 

acids (five)(HAA5). 

(b) Applicability. You are subject to 

these requirements if your system is a 

community water system or 

nontransient noncommunity water 

system that adds a primary or residual 

disinfectant other than ultraviolet light 

or delivers water that has been treated 

with a primary or residual disinfectant 

other than ultraviolet light. 

(c) Schedule. You must comply with 

the requirements in this subpart on the 

schedule in the following table, based 

on your system type.

If you are this type of system You must comply with subpart V by: 123

(1) Subpart H serving ≥10,000 ........................... [date 72 mos following publication of final rule]. 

(2) Subpart H serving <10,000 ........................... [date 90 mos following publication of final rule] if no Cryptosporidium monitoring is required 

under § 141.706(c) OR 

[date 102 mos following publication of final rule] if Cryptosporidium monitoring is required 

under § 141.706(c). 

(3) Ground water serving ≥10,000 ..................... [date 72 mos following publication of final rule]. 

(4) Ground water serving <10,000 ..................... [date 90 mos following publication of final rule]. 

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49677

If you are this type of system You must comply with subpart V by: 123

(5) Consecutive system ...................................... —at the same time as the system with the earliest compliance date in the combined distribution system. 

1The State may grant up to an additional 24 months for compliance if you require capital improvements. 

2 If you are required to conduct quarterly monitoring, you must begin monitoring in the first full calendar quarter that follows the compliance 

date in this table. If you are required to conduct monitoring at a frequency that is less than quarterly, you must begin monitoring in the calendar 

month recommended in the IDSE report prepared under § 141.604 no later than 12 months after the compliance date in this table. If you are not 

required to submit an IDSE report, you must begin monitoring during the calendar month identified in the monitoring plan developed under 

§ 141.622 no later than 12 months after the compliance date. 

3 If you are required to conduct quarterly monitoring, you must make compliance calculations at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter (or earlier if the LRAA calculated based on fewer than four quarters of data 

would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters). If you are required to conduct monitoring at a 

frequency that is less than quarterly, you must make compliance calculations beginning with the first compliance sample taken after the compliance date. 

(d) Monitoring and compliance. You 

must monitor at sampling locations 

identified in your monitoring plan 

developed under § 141.622. To 

determine compliance with subpart V 

MCLs, you must calculate locational 

running annual averages for TTHM and 

HAA5 using monitoring results 

collected under this subpart. If you fail 

to complete four consecutive quarters of 

monitoring, you must calculate 

compliance with the MCL based on an 

average of the available data from the 

most recent four quarters. 

(e) Violations. You must comply with 

specific monitoring and reporting 

requirements. Failure to monitor in 

accordance with the monitoring plan 

required under § 141.622 is a 

monitoring violation. Failure to monitor 

will also be treated as a monitoring 

violation for the entire period covered 

by a locational running annual average 

compliance calculation for the subpart 

V MCLs in § 141.64(b)(3). 

(f) Additional provisions.

(1) You may consider multiple wells 

drawing water from a single aquifer as 

one treatment plant for determining the 

minimum number of TTHM and HAA5 

samples required, with State approval in 

accordance with criteria developed 

under § 142.16(h)(5) of this chapter. 

Approvals made under §§ 141.132(a)(2) 

and 141.601(d) remain in effect unless 

withdrawn by the State. 

(2) Consecutive systems. For the 

purposes of this subpart, you must 

determine whether you buy all or some 

of your water based on your 

categorization for the IDSE under 

subpart U, unless otherwise directed by 

the State. If you were not categorized 

under subpart U, you must determine 

whether you buy all or some of your 

water based on your categorization 

during 2005, unless otherwise directed 

by the State. 

(3) For the purposes of determining 

monitoring requirements of this subpart, 

each consecutive system entry point 

from a wholesale system to a 

consecutive system that buys some, but 

not all, of its finished water is 

considered a treatment plant for that 

consecutive system. 

(i) You may request that the State 

allow multiple consecutive system entry 

points from a single wholesale system to 

a single consecutive system to be 

considered one treatment plant. 

(ii) In the request to the State for 

approval of multiple consecutive system 

entry points to be considered one 

treatment plant, you must demonstrate 

that factors such as relative locations of 

entry points, detention times, sources, 

and the presence of treatment (such as 

corrosion control or booster 

disinfection) will have a minimal 

differential effect on TTHM and HAA5 

formation associated with individual 

entry points.

§ 141.621 Routine monitoring. 

(a) You must monitor at the locations 

and frequencies listed in the following 

table.

If you are this type of 

system Then you must monitor At these locations for each treatment plant 1

(1) Subpart H serving 

≥10,000.

four dual sample sets per quarter per treatment plant, 

taken approximately every 90 days. One quarterly set 

must be taken during the peak historical month for 

DBP concentrations 2.

—locations recommended to the State in the IDSE report submitted under subpart U. 

(2) Subpart H serving 500–

9,999.

two dual sample sets per quarter per treatment plant, 

taken approximately every 90 days. One quarterly set 

must be taken during the peak historical month for 

DBP concentrations 2.

—locations recommended to the State in the IDSE report submitted under subpart U.3

(3) Subpart H serving <500 one TTHM and one HAA5 sample per year per treatment plant, taken during the peak historical month for 

DBP concentrations.

—locations recommended to the State in the IDSE report submitted under subpart U.4

(4) Ground water serving 

≥10,000.

two dual sample sets per quarter per treatment plant, 

taken approximately every 90 days. One quarterly set 

must be taken during the peak historical month for 

DBP concentrations 2.

—locations recommended to the State in the IDSE report submitted under subpart U.3

(5) Ground water serving 

500–9,999.

two dual sample sets per year per treatment plant, 

taken during the peak historical month for DBP concentrations 2.

—locations recommended to the State in the IDSE report submitted under subpart U.3

(6) Ground water serving 

<500.

one TTHM and one HAA5 sample per year per treatment plant, taken during the peak historical month for 

DBP concentrations.

—locations recommended to the State in the IDSE report submitted under subpart U.4

(7) Consecutive system that 

buys some, but not all, of 

its finished water.

based on your own population and source water, except that consecutive systems that receive water from 

a subpart H system must monitor as a subpart H system.

—locations recommended to the State in the IDSE report submitted under subpart U. 

49678 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

If you are this type of 

system Then you must monitor At these locations for each treatment plant 1

(8) Consecutive system that 

buys all its finished water.

as specified in § 141.605(e) ............................................. —locations recommended to the State in the IDSE report submitted under subpart U. 

1 Unless the State has approved or required other locations or additional locations based on the IDSE report or other information, or you have 

updated the monitoring plan under § 141.622. 2A dual sample set is a set of two samples collected at the same time and same location, with one sample analyzed for TTHM and the other 

sample analyzed for HAA5. 3 If you have a single location that has both the highest TTHM LRAA and highest HAA5 LRAA, you may take a dual sample set only at that location after approval by the State. 4You are required to sample for both TTHM and HAA5 at one location if that location is the highest for both TTHM and HAA5. If different locations have high TTHM and HAA5 LRAAs, you may sample for TTHM only at the high TTHM location and for HAA5 only at the high HAA5 location. If you have received a very small system waiver for IDSE monitoring from the State under § 141.603(c), you must monitor for TTHM and 

HAA5 as a dual sample set at the subpart L monitoring location (a point representative of maximum residence time) during the month of warmest 

water temperature. 

(b) You must begin monitoring at the 

locations you have recommended in 

your IDSE report submitted under 

§ 141.604 following the schedule in 

§ 141.620(c), unless the State requires 

other locations or additional locations 

after its review. If you have received a 

very small system waiver under 

§ 141.603(c), you must monitor at the 

location(s) identified in your monitoring 

plan in § 141.132(f), updated as required 

by § 141.622. 

(c) You must use an approved method 

listed in § 141.131 for TTHM and HAA5 

analyses in this subpart. Analyses must 

be conducted by laboratories that have 

received certification by EPA or the 

State as specified in § 141.131.

§ 141.622 Subpart V monitoring plan. 

(a) You must develop and implement 

a monitoring plan to be kept on file for 

State and public review. You may 

comply by updating the monitoring plan 

developed under § 141.132(f) no later 

than the date identified in § 141.620(c) 

for subpart V compliance. If you have 

received a very small system waiver 

under § 141.603(c), you must comply by 

updating the monitoring plan developed 

under § 141.132(f) no later than the date 

identified in § 141.620(c) for subpart V 

compliance. The monitoring plan must 

contain the elements in paragraphs 

(a)(1) through (a)(5) of this section: 

(1) Monitoring locations; 

(2) Monitoring dates; 

(3) Compliance calculation 

procedures; 

(4) Monitoring plans for any other 

systems in the combined distribution 

system if monitoring requirements have 

been modified based on data from other 

systems; and 

(5) Any permits, contracts, or 

agreements with third parties (including 

other PWSs, laboratories, and State 

agencies) to sample, analyze, report, or 

perform any other system requirement 

in this subpart. 

(b) The monitoring plan will reflect 

the recommendations of the IDSE report 

required under subpart U, along with 

any State-mandated modifications. The 

State must approve any monitoring sites 

for which you are required to provide a 

rationale in your IDSE report by 

§ 141.605(a)(4). 

(c) If you are a subpart H system 

serving more than 3,300 people, you 

must submit a copy of your monitoring 

plan to the State prior to the date you 

are required to comply with the 

monitoring plan. 

(d) You may modify your monitoring 

plan to reflect changes in treatment, 

distribution system operations and 

layout (including new service areas), or 

other factors that may affect TTHM or 

HAA5 formation. If you change 

monitoring locations, you must replace 

locations with the lowest LRAA and 

notify the State how new sites were 

selected as part of the next report due 

under § 141.630. The State may also 

require modifications in your 

monitoring plan.

§ 141.623 Reduced monitoring. 

(a) Systems other than consecutive 

systems that buy all their water. You 

may reduce monitoring by meeting the 

criteria in the table in this paragraph at 

all treatment plants in the system. You 

may only use data collected under the 

provisions of this subpart or subpart L 

of this part to qualify for reduced 

monitoring.

If you are this type of 

system 

Then you may reduce monitoring if you have 

monitoring results under § 141.621 and 

To reduce monitoring per plant at these locations/frequency 

TTHM HAA5 

(1) Subpart H serving 

≥10,000.

—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations, AND 

—monitor once per quarter by taking a dual 

sample set at the location with the highest 

TTHM LRAA or single measurement.

—monitor once per quarter by taking a dual 

sample set at the location with the highest 

HAA5 LRAA or single measurement. 

—the source water annual average TOC 

level, before any treatment, is ≤4.0 mg/L at 

each subpart H treatment plant 1.

(2) Subpart H serving 

500–9,999.

—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations, AND 

—monitor once per year by taking a dual 

sample set at the location with the highest 

TTHM single measurement during the 

quarter that the highest single TTHM 

measurement occurred 2.

—monitor once per year by taking a dual 

sample set at the location with the highest 

HHA5 single measurement during the 

quarter that the highest single HHA5 

measurement occurred.2

—the source water annual average TOC 

level, before any treatment, is ≤4.0 mg/L at 

each subpart H treatment plant 1.

(3) Subpart H serving 

<500.

—monitoring may not be reduced to fewer 

than one TTHM sample and one HAA5 

sample per year.

not applicable ................................................. not applicable. 

(4) Ground water serving ≥10,000.—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations.

—monitor once per year by taking a dual 

sample set at the location with the highest 

TTHM single measurement during the 

quarter that the highest single TTHM 

measurement occurred 2.

—monitor once per year by taking a dual 

sample set at the location with the highest 

HHA5 single measurement during the 

quarter that the highest single HHA5 

measurement occurred.2

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49679

If you are this type of 

system 

Then you may reduce monitoring if you have 

monitoring results under § 141.621 and 

To reduce monitoring per plant at these locations/frequency 

TTHM HAA5 

(5) Ground water serving 500–9,999.—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations.

—monitor once every third year by taking a 

dual sample set at the location with the 

highest TTHM single measurement during 

the quarter that the highest single TTHM 

measurement occurred 2.

—monitor once every third year by taking a 

dual sample set at the location with the 

highest HHA5 single measurement during 

the quarter that the highest single HHA5 

measurement occurred.2

(6) Ground water serving <500.—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations.

—monitor once every third year for TTHM at 

the location with the highest TTHM single 

measurement during the quarter that the 

highest single TTHM measurement occurred 2.

—monitor once every third year for HAA5 at 

the location with the highest HAA5 single 

measurement during the quarter that the 

highest single HAA5 measurement occurred.2

(7) Consecutive system that buys some, 

but not all, of its finished water 3.

—the LRAA is ≤0.040 mg/L for TTHM and 

≤0.030 for HAA5 at ALL monitoring locations.

—monitor at the location(s) and frequency 

associated with a non-consecutive system 

with the same population and source water 

type.

—monitor at the location(s) and frequency 

associated with a non-consecutive system 

with the same population and source water 

type.2

1TOC monitoring must comply with the provisions of either § 141.132(d) or § 141.132(e). 2 If your location for reduced monitoring for TTHM and HAA5 is the same location and if your quarter for the highest TTHM and HAA5 single measurement is the 

same, you may take one dual sample set at that location during that quarter. 3 Consecutive systems that buy some, but not all, of their finished water may reduce monitoring based on their own population and their wholesale system(s)’s source water type to the frequency and location(s) required in this section, unless the consecutive system treats surface water or ground water under the direct influence of surface water. If the consecutive system treats surface water or ground water under the direct influence of surface water, it must base reduced monitoring on 

its population and classification as a subpart H system. 

(b) Consecutive systems that buy all 

their water. You may reduce monitoring 

to the level specified in the table in this 

paragraph if the LRAA is ≤0.040 mg/L 

for TTHM and ≤0.030 mg/L for HAA5 at 

all monitoring locations. You may only 

use data collected under the provisions 

of this subpart or subpart L of this part 

to qualify for reduced monitoring.

REDUCED MONITORING FREQUENCY FOR CONSECUTIVE SYSTEMS THAT BUY ALL THEIR WATER. 

Population Reduced monitoring frequency and location 

Subpart H systems

<500 ........................................ Monitoring may not be reduced. 

500 to 4,999 ............................ 1 TTHM and 1 HAA5 sample per year at different locations or during different quarters if the highest TTHM and 

HAA5 measurements occurred at different locations or different quarters or 1 dual sample set per year if the 

highest TTHM and HAA5 measurements occurred at the same location and quarter. 

5,000 to 9,999 ......................... 2 dual sample sets per year; one at the location with the highest TTHM single measurement during the quarter 

that the highest single TTHM measurement occurred, one at the location with the highest HAA5 single measurement during the quarter that the highest single HAA5 measurement occurred. 

10,000 to 24,999 ..................... 2 dual sample sets per quarter at the locations with the highest TTHM and highest HAA5 LRAAs. 

25,000 to 49,999 ..................... 2 dual sample sets per quarter at the locations with the highest TTHM and highest HAA5 LRAAs. 

50,000 to 99,000 ..................... 4 dual sample sets per quarter—at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

100,000 to 499,999 ................. 4 dual sample sets per quarter—at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

500,000 to 1,499,999 .............. 6 dual sample sets per quarter—at the locations with the three highest TTHM and three highest HAA5 LRAAs. 

1,500,000 to 4,999,999 ........... 6 dual sample sets per quarter—at the locations with the three highest TTHM and three highest HAA5 LRAAs. 

>=5,000,000 ............................ 8 dual sample sets per quarter at the locations with the four highest TTHM and four highest HAA5 LRAAs. 

Ground water systems

<500 ........................................ 1 TTHM and 1 HAA5 sample every third year at different locations and time if the highest TTHM and HAA5 

measurements occurred at different locations and/or time or 1 dual sample set every third year if the highest 

TTHM and HAA5 measurements occurred at the same location and time of year. 

500 to 9,999 ............................ 1 TTHM and 1 HAA5 sample every year at different locations and time if the highest TTHM and HAA5 measurements occurred at different locations and/or time or 1 dual sample set every year if the highest TTHM and 

HAA5 measurements occurred at the same location and time of year. 

10,000 to 99,000 ..................... 2 dual sample sets per year; one at the location with the highest TTHM single measurement during the quarter 

that the highest single TTHM measurement occurred and one at the location with the highest HAA5 single 

measurement during the quarter that the highest single HAA5 measurement occurred. 

100,000 to 499,999 ................. 2 dual sample sets per quarter; at the locations with the highest TTHM and highest HAA5 LRAAs. 

≥500,000 ................................. 4 dual sample sets per quarter; at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

(c) You may remain on reduced 

monitoring as long as the TTHM LRAA 

≤0.040 mg/L and the HAA5 LRAA 

≤0.030 mg/L at each monitoring location 

(for systems with quarterly monitoring) 

or each TTHM sample ≤0.060 mg/L and 

each HAA5 sample ≤0.045 mg/L (for 

systems with annual or less frequent 

monitoring). In addition, the source 

water annual average TOC level, before 

any treatment, must be ≤4.0 mg/L at 

each treatment plant treating surface 

water or ground water under the direct 

influence of surface water, based on 

monitoring conducted under either 

§§ 141.132(d) or 141.132(e). If the LRAA 

at any location exceeds either 0.040 mg/

L for TTHM or 0.030 mg/L for HAA5 or 

if the annual (or less frequent) sample 

at any location exceeds either 0.060 mg/

L for TTHM or 0.045 mg/L for HAA5, 

or if the source water annual average 

TOC level, before any treatment, >4.0 

mg/L at any treatment plant treating 

surface water or ground water under the 

direct influence of surface water, the 

system must resume routine monitoring

49680 Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 

under § 141.621 for all treatment plants 

or begin increased monitoring for all 

treatment plants if § 141.625 applies. 

(d) The State may return your system 

to routine monitoring at the State’s 

discretion.

§ 141.624 Additional requirements for 

consecutive systems. 

If you are a consecutive system that 

does not add a disinfectant but delivers 

water that has been disinfected with 

other than ultraviolet light, you must 

comply with monitoring requirements 

for chlorine and chloramines in 

§ 141.132(c)(1) and the compliance 

requirements in § 141.133(c)(1) 

beginning [date three years after 

publication of final rule] and report 

monitoring results under § 141.134(c), 

unless required earlier by the State.

§ 141.625 Conditions requiring increased 

monitoring. 

(a) If you are required to monitor at 

a particular location yearly or less 

frequently than yearly under §§ 141.621 

or 141.623, you must increase 

monitoring to dual sample sets once per 

quarter (taken approximately every 90 

days) at all locations if either the annual 

(or less frequent) TTHM sample >0.080 

mg/L or the annual (or less frequent) 

HAA5 sample >0.060 mg/L at any 

location. 

(b) You are not in violation of the 

MCL until the LRAA calculated based 

on four consecutive quarters of 

monitoring (or the LRAA calculated 

based on fewer than four quarters of 

data if the MCL would be exceeded 

regardless of the monitoring results of 

subsequent quarters) exceeds the 

subpart V MCLs in § 141.64(b)(3). You 

are in violation of the monitoring 

requirements for each quarter that a 

monitoring result would be used in 

calculating an LRAA if you fail to 

monitor. 

(c) You may return to routine 

monitoring once you have conducted 

increased monitoring for at least four 

consecutive quarters and the LRAA for 

every location is ≤0.060 mg/L for TTHM 

and ≤0.045 mg/L for HAA5.

§ 141.626 Significant excursions. 

If a significant excursion occurs, you 

must conduct a significant excursion 

evaluation and prepare a written report 

of the evaluation no later than 90 days 

after being notified of the analytical 

result that shows the significant 

excursion. You must discuss the 

evaluation with the State no later than 

the next sanitary survey for your system. 

Your evaluation must include an 

examination of distribution system 

operational practices that may 

contribute to TTHM and HAA5 

formation (such as flushing programs 

and storage tank operations and excess 

capacity) and how these practices may 

be modified to reduce TTHM and HAA5 

levels.

§ 141.627 Requirements for remaining on 

reduced TTHM and HAA5 monitoring based 

on subpart L results. 

You may remain on reduced 

monitoring after the dates identified in 

§ 141.620(c) for compliance with this 

subpart only if you qualify for a 40/30 

certification under § 141.603(b) or have 

received a very small system waiver 

under § 141.603(c), plus you meet the 

reduced monitoring criteria in 

§ 141.623(c), and you do not change or 

add monitoring locations from those 

used for compliance monitoring under 

subpart L. If your monitoring locations 

under this subpart differ from your 

monitoring locations under subpart L, 

you may not remain on reduced 

monitoring after the dates identified in 

§ 141.620(c) for compliance with this 

subpart.

§ 141.628 Requirements for remaining on 

increased TTHM and HAA5 monitoring 

based on subpart L results. 

If you were on increased monitoring 

under subpart L, you must remain on 

increased monitoring until you qualify 

for a return to routine monitoring under 

§ 141.625(c). You must conduct 

increased monitoring under § 141.625 at 

the monitoring locations in the 

monitoring plan developed under 

§ 141.622 beginning at the date 

identified in § 141.620(c) for compliance 

with this subpart and remain on 

increased monitoring until you qualify 

for a return to routine monitoring under 

§ 141.625(c).

§ 141.629 [Reserved]

§ 141.630 Reporting and recordkeeping 

requirements. 

(a) Reporting. (1) You must report the 

following information for each 

monitoring location to the State within 

10 days of the end of any quarter in 

which monitoring is required: 

(i) Number of samples taken during 

the last quarter. 

(ii) Date and results of each sample 

taken during the last quarter. 

(iii) Arithmetic average of quarterly 

results for the last four quarters 

(LRAAs). 

(iv) Whether the MCL was violated. 

(2) If you are a subpart H system 

seeking to qualify for or remain on 

reduced TTHM/HAA5 monitoring, you 

must report the following source water 

TOC information for each treatment 

plant that treats surface water or ground 

water under the direct influence of 

surface water to the State within 10 days 

of the end of any quarter in which 

monitoring is required: 

(i) The number of source water TOC 

samples taken each month during last 

quarter. 

(ii) The date and result of each sample 

taken during last quarter. 

(iii) The quarterly average of monthly 

samples taken during last quarter. 

(iv) The running annual average 

(RAA) of quarterly averages from the 

past four quarters. 

(v) Whether the RAA exceeded 4.0 

mg/L. 

(b) Recordkeeping. You must retain 

any subpart V monitoring plans and 

your subpart V monitoring results as 

required by § 141.33.

PART 142— NATIONAL PRIMARY 

DRINKING WATER REGULATIONS 

IMPLEMENTATION 

1. The authority citation for part 142 

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g–1, 300g–2, 

300g–3, 300g–4, 300g–5, 300g–6, 300j–4, 

300j–9, and 300j–11.

2. Section 142.14 is amended by 

adding paragraph (a)(8) to read as 

follows:

§ 142.14 Records kept by States. 

(a) * * * 

(8) Any decisions made pursuant to 

the provisions of 40 CFR part 141, 

subparts U and V of this chapter. 

(i) Those systems for which the State 

has determined that the 40 CFR part 

141, subpart L approved monitoring site 

is representative of the highest TTHM 

and HAA5 and therefore have been 

granted a very small system waiver 

under § 141.603(c) of this chapter. The 

State must provide a copy of the 

decision to the system. A copy of the 

decision must be kept until reversed or 

revised. 

(ii) System IDSE reports, plus any 

modifications required by the State. 

Reports must be kept until reversed or 

revised in their entirety.

* * * * *

3. Section 142.16 is amended by 

adding paragraph (m) to read as follows:

§ 142.16 Special primacy conditions.

* * * * *

(m) Requirements for States to adopt 

40 CFR part 141, subparts U and V. In 

addition to the general primacy 

requirements elsewhere in this part, 

including the requirements that State 

regulations be at least as stringent as 

federal requirements, an application for 

approval of a State program revision 

that adopts 40 CFR part 141, subparts U

Federal Register / Vol. 68, No. 159 / Monday, August 18, 2003 / Proposed Rules 49681

and V, must contain a description of 

how the State will accomplish the 

following:

(1) For PWSs serving fewer than 500 

people, a very small system waiver 

procedure for subpart U IDSE 

requirements that will apply to all 

systems that serve fewer than 500 

people without the State making a 

system-by-system waiver determination, 

if the State elects to use such an 

authority. 

(2) A procedure for evaluating systemspecific studies under § 141.603(a) of 

this chapter, if system-specific studies 

are conducted in the State. 

(3) A procedure for determining that 

multiple consecutive system entry 

points from a single wholesale system to 

a single consecutive system should be 

treated as a single treatment plant for 

monitoring purposes. 

(4) A procedure for addressing 

consecutive systems outside the 

provisions of § 141.29 of this chapter or 

part 141 subparts U and V of this 

chapter, if the State elects to use such 

an authority. 

(5) A procedure for systems to 

identify significant excursions.

PART 143—NATIONAL SECONDARY 

DRINKING WATER REGULATIONS 

1. The authority citation for part 143 

continues to read as follows:

Authority: 42 U.S.C. 300f et seq.

2. In § 143.4, the table in paragraph (b) 

is amended by revising entries 2 and 9 

and footnotes 3 and 4, and by adding 

footnote 6 to read as follows:

§ 143.4 Monitoring.

* * * * *

(b) * * *

Contaminant EPA ASTM 3 SM 4 18th and 19th ed. SM 4 20th ed. Other 

* * * * * * * 

2. Chloride ............................... 300.0 1 D4327–97 .... 4110 B .................................... 4110 B.

300.1 6 ...................... ................................................. .

...................... 4500–Cl ¥D ............................ 4500–Cl ¥D ............................ ....................

D512–89B .... 4500–Cl¥B ............................. 4500–Cl¥B ............................. ....................

* * * * * * * 

9. Sulfate ................................. 300.0 1 D4327–97 .... 4110B ..................................... 4110B.

300.1 6 ...................... ................................................. ................................................. ....................

375.2 1 ...................... 4500–SO4 2¥F ........................ 4500–SO4 2¥F.

4500–SO4 2¥C, D ................... 4500–SO 4 2¥C, D.

D516–90 ...... 4500–SO4 2¥E ....................... 4500–SO4 2¥E.

* * * * * * * 

* * * * * 

1 ‘‘Methods for the Determination of Inorganic Substances in Environmental Samples’’, EPA/600/R–93–100, August 1993. Available at NTIS, 

PB94–120821. 

* * * * * 

3Annual Book of ASTM Standards, 1994, 1996, or 1999, Vols. 11.01 and 11.02, ASTM International; any year containing the cited version of 

the method may be used. Copies may be obtained from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. 4Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998). American 

Public Health Association, 1015 Fifteenth Street, NW, Washington, DC 20005. The cited methods published in any of these three editions may 

be used, except that the versions of 3111 B, 3111 D, and 3113 B in the 20th edition may not be used. 

* * * * * 

6 ‘‘Methods for the Determination of Organic and Inorganic Compounds in Drinking Water’’, Vol. 1, EPA 815-R–00–014, August 2000. Available 

at NTIS, PB2000–106981. 

[FR Doc. 03–18149 Filed 8–15–03; 8:45 am] 

BILLING CODE 6560–50–P