United States Office of Water EPA 816-R-01-011

Environmental Protection (4606) June 2001

Agency

Implementation Guidance

for the 

Interim Enhanced Surface

Water Treatment Rule 
This document does not substitute for EPA regulation nor is this

document regulation itself. Thus, it cannot impose legally-binding

requirements on EPA, states, or the regulated community, and may

not apply to a particular situation based upon the circumstances.
IESWTR Implementation Guidance i June 2001

Contents

Introduction ................................................................. ix

Section I. Rule Requirements ................................................. 1

A. IESWTR Executive Summary .......................................... 3

B. Key Dates for the IESWTR ............................................ 9

Section II. SDWIS Reporting and SNC Definitions .................................. 1

A. Safe Drinking Water Information System (SDWIS) Reporting Under the IESWTR ..... 3

A.1 Federally Reported Violations ..................................... 3

B. SNC Definitions for the IESWTR ....................................... 11

Section III. State Primacy Revision Applications .................................... 1

A. State Primacy Program Revision ......................................... 3

A.1 The Revision Process .......................................... 5

A.2 The Final Review Process ....................................... 7

B. State Primacy Program Revision Extensions ................................ 7

B.1 The Extension Process .......................................... 7

B.2 Criteria that an Extension Request Must Meet ......................... 7

B.3 Conditions of the Extension ...................................... 8

C. State Primacy Package .............................................. 10

C.1 Section I—The State Primacy Revision Checklist (40 CFR 142.10) ......... 10

C.2 Section II—Text of the State’s Regulation ........................... 11

C.3 Section III—Primacy Revision Crosswalk ........................... 11

C.4 Section IV—State Reporting and Recordkeeping Checklists .............. 11

C.5 Section V—Special Primacy Requirements (40 CFR 142.16) ............. 12

C.6 Section VI—Attorney General’s Statement of Enforceability .............. 12

D. Guidance for IESWTR Special Primacy Requirements ........................ 15

Section IV. Other Resources and Guidance ........................................ 1

A. Technical Information Available on the IESWTR ............................. 3

B. Profiling Spreadsheet ................................................. 5

C. List of Labs Approved to Perform Analysis for ICR ........................... 5

D. Rule Presentation ................................................... 5

E. Fact Sheets ........................................................ 6

F. Frequently Asked Questions ........................................... 25

Appendices

Appendix A Primacy Revision Crosswalk ......................................... A-1

Appendix B Sample Extension Agreement ......................................... B-1

Appendix C Statement of Principles—Guidance on Audit Law Issues ..................... C-1

Appendix D IESWTR Plain English Summary ...................................... D-1

Appendix E IESWTR Rule Language ............................................ E-1

Appendix F Examples of IESWTR Monitoring Forms for States ......................... F-1
June 2001 ii IESWTR Implementation Guidance

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IESWTR Implementation Guidance iii June 2001

Regional Contacts

Region I

Kevin Reilly

617-918-1694

Linda Tsang

617-918-1395

Region II

Michael Lowy

212-637-3830

Region III

Jason Gambatese

215-814-5759

Region IV

David Parker

404-562-9460

Region V

Miguel Del Toral

312-886-5253

Region VI

Blake Atkins

214-665-2297

Region VII

Ralph Flournoy

913-551-7374

Region VIII

Bob Clement

303-312-6653

Region IX

Bruce Macler

415-744-1884

Region X

Wendy Marshall

206-553-1890
June 2001 iv IESWTR Implementation Guidance

State Contacts

REGION I

Connecticut

Gerald Iwan

Maine

Nancy Beardsley

Massachusetts

David Terry

New Hampshire

Anthony Giunta

Rhode Island

June Swallow

Vermont

Jay Rutherford

REGION II

New Jersey

Vince Monaco

New York 

Ron Entringer

Puerto Rico

Olga Rivera

US Virgin Islands

Christine Lottis

REGION III

Delaware

Ed Hallock

Maryland

Nancy Reilman

Pennsylvania

John Wroblewski

Virginia

John Capito

Bob Taylor

West Virginia

Vic Wilford

REGION IV

Alabama

Joe Alan Power

Florida

Van Hoofnagle

Georgia

Onder Serefli

Kentucky

Vicki Ray

Mississippi

David Mitchell

North Carolina

Jessica Miles

South Carolina

Alton C. Boozer

Tennessee

W. David Draughon
IESWTR Implementation Guidance v June 2001

REGION V

Illinois

Dave Antonacci

Mike Crumly

Jerry Kuhn

Eric Portz

Roger Selburg

Indiana

Stacy Jones

Jill Shalabi

Michigan

James Cleland

Minnesota

Dennis E. Maki

Ohio

Kirk Leifheit

Wisconsin

Robert Baumeister

REGION VI

Arkansas

Harold R. Seifert

Louisiana

Bobby Savoie

New Mexico

Robert Gallegos

Oklahoma

Jon L. Craig

Texas

Steven Walden

REGION VII

Iowa

Dennis Alt

Kansas

Dave Waldo

Missouri

Terry Timmons

Nebraska

Jack Daniel

REGION XIII

Colorado

Jerry Biberstine

Montana

John Camden

North Dakota

Larry Thelen

South Dakota

Garland Erbele

Utah

Russ Topham

Wyoming

Gary Beach

REGION IX

American Samoa

Sheila Wiegman

Arizona

Jeff Stuck

California

David P. Spath

Guam

Fred Castro

Hawaii

Bill Wong

Nevada

Galen Denio

Northern Mariana Islands

Miriam Seman

REGION X

Alaska

James Weise

Idaho

Tom John

Oregon

Michael Grimm

Washington

Jim Hudson
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IESWTR Implementation Guidance vii June 2001

Abbreviations Used in This Document

“C”: Residual Disinfectant Concentration

BAT: Best Available Technology

CCP: Composite Correction Program

CCR: Consumer Confidence Report

CDC: Centers for Disease Control

CFE: Combined Filter Effluent

CFR: Code of Federal Regulations

CPE: Comprehensive Performance Evaluation

CT: Residual Disinfectant Concentration in mg/l “C” x Disinfectant Contact Time in min “T”

CTA: Comprehensive Technical Assistance

CWS: Community Water System

DBP: Disinfection Byproducts

DBPP: Disinfection Byproducts Precursors 

DBPR: Disinfectants/Disinfection Byproducts Rule

DE: Diatomaceous Earth

DTF: Data Transfer Format

DWPD: Drinking Water Protection Division

EC: Enhanced Coagulation

EPA: United States Environmental Protection Agency

ES: Enhanced Softening

ESWTR: Enhanced Surface Water Treatment Rule

FACA: Federal Advisory Committee Act

FR: Federal Register

FRDS: Federal Reporting Data System

GAC10: Granular activated carbon with ten minute empty bed contact time and 180 day reactivation

frequency

GWR: Ground Water Rule

GWUDI: Ground Water Under the Direct Influence of Surface Water

HAA5: Haloacetic acids (Monochloroacetic, Dichloroacetic, Trichloroacetic, Monobromoacetic and

Dibromoacetic Acids)

HAV: Hepatitis A Virus

hrs: Hours

ICR: Information Collection Rule

IESWTR: Interim Enhanced Surface Water Treatment Rule

IFA: Individual Filter Assessment

Log Inactivation: Logarithm of (N0/NT)

Log: Logarithm (common, base 10)

LT1ESWTR: Long Term 1 Enhanced Surface Water Treatment Rule

LT2ESWTR: Long Term 2 Enhanced Surface Water Treatment Rule

LTESWTR: Long Term Enhanced Surface Water Treatment Rule

MCL: Maximum Contaminant Level

MCLG: Maximum Contaminant Level Goal

M–DBP: Microbial and Disinfectants/Disinfection Byproducts
June 2001 viii IESWTR Implementation Guidance

MPA: Microscopic Particulate Analysis

M/R: Monitoring/Reporting

MRDL: Maximum Residual Disinfectant Level

MRDLG: Maximum Residual Disinfectant Level Goal

NCWS: Non-Community Water System

NIPDWR: National Interim Primary Drinking Water Regulation

NPDES: National Pollutant Discharge Elimination System

NPDWR: National Primary Drinking Water Regulation

NSCEP: National Service for Environmental Publications

NTIS: National Technical Information Service

NTNCWS: Non-Transient Non-Community Water System

NTU: Nephelometric Turbidity Unit

OAR: Office of Air and Radiation

OECA: Office of Enforcement and Compliance Assurance

OGC: Office of General Counsel

OGWDW: Office of Ground Water and Drinking Water

OMB: Office of Management and Budget

ORC: Office of Regional Counsel 

OSWER: Office of Solid Waste and Emergency Response

OW: Office of Water

PWS: Public Water System

PWSS: Public Water Supply Supervision Program

Reg. Neg.: Regulatory Negotiation

SDWA: Safe Drinking Water Act, or “The Act,” as amended 1996

SDWIS: Safe Drinking Water Information System

SNC: Significant Non-Compliance

Subpart H: PWS using surface water or ground water under the direct influence of surface water 

SUVA: Specific Ultraviolet Absorption

SWTR: Surface Water Treatment Rule

“T”: Disinfectant Contact Time

TCR: Total Coliform Rule

TNCWS: Transient Non-Community Water System

TOC: Total Organic Carbon

TT: Treatment Technique

TTHM: Total Trihalomethanes

UV: Ultraviolet

x log removal: Reduction to 1 /10x of original concentration
IESWTR Implementation Guidance ix June 2001

Introduction

This document provides guidance to EPA Regions and states exercising primary enforcement responsibility

under the Safe Drinking Water Act (SDWA) concerning how EPA interprets the Interim Enhanced Surface

Water Treatment Rule (IESWTR) under SDWA. It also provides guidance to the public and the regulated

community on how EPA intends to exercise its discretion in implementing the statute and regulations. This

guidance is designed to implement national policy on these issues. 

The SDWA provisions and EPA regulations described in this document contain legally binding requirements.

This document does not substitute for those provisions or regulations, nor is it a regulation itself. It does not

impose legally-binding requirements on EPA, states, or the regulated community, and may not apply to a

particular situation based upon the circumstances. EPA and state decisionmakers retain the discretion to

adopt approaches on a case-by-case basis that differ from this guidance where appropriate. Any decisions

regarding a particular facility will be made based on the applicable statutes and regulations. Therefore,

interested parties are free to raise questions and objections about the appropriateness of the application of

this guidance to a particular situation, and EPA will consider whether or not the recommendations or

interpretations in the guidance are appropriate in that situation based on the law and regulations. EPA may

change this guidance in the future.

This manual was developed through a workgroup process involving Regions, states, and stakeholders, and

contains the following sections:

Section I summarizes the IESWTR and presents a timetable of important dates for this rule. Section II

addresses violation determination and associated reporting requirements to assist states in their compliance

activities. Section III covers state primacy revision requirements, including a detailed timeframe for

application review and approval. This section also contains guidance and references to help states adopt

each new special primacy requirement included in these rules. Section IV contains a series of “stand-alone”

guidance materials that will help states and public water systems comply with the new requirements. 

The Appendices of this document also provide information that will be useful to states and EPA Regions

throughout the primacy revision application process. Appendix A contains the primacy revision application

crosswalk for the rule. Appendix B contains a sample extension agreement between EPA and a state which

will allow the state and EPA to document how they will share rule implementation responsibilities if the state

does not submit a primacy application by the deadline. Appendix C contains a “Statement of Principles”

which outlines the criteria EPA will use to determine whether states with audit laws have retained adequate

enforcement and information gathering authority to meet the requirements of the Safe Drinking Water Act

(SDWA). Appendix D contains a Plain English summary of the rule. Appendix E contains the rule language

of IESWTR incorporating the technical amendments. Appendix F contains sample monitoring forms that

can be used as a template by states developing their own forms.

EPA and state decision makers retain the discretion to adopt approaches on a case-by-case basis that differ

from this guidance where appropriate. Any decisions regarding a particular facility will be made based on the

applicable statutes and regulations. Therefore, interested parties are free to raise questions and objections

about the appropriateness of the application of this guidance to a particular situation, and EPA will consider

whether or not the recommendations or interpretations in the guidance are appropriate in that situation. EPA

may change this guidance in the future.
June 2001 x IESWTR Implementation Guidance

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Section I. 

Rule Requirements
June 2001 I-2 IESWTR Implementation Guidance

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IESWTR Implementation Guidance I-3 June 2001

I-A. IESWTR Executive Summary

Purpose

The purpose of this summary is to acquaint state decision-makers and public health officials with the Interim

Enhanced Surface Water Treatment Rule (IESWTR). The IESWTR, published in the Federal Register on

December 16, 1998 (63 FR 69478; www.epa.gov/OGWDW/mdbp/ieswtrfr.html; 66 FR 3770;

www.epa.gov/safewater/mdbp/iesfr.html; Appendix E—rule language only), is the first part of a series of

rules, the “Microbial-Disinfectants/Disinfection Byproducts Cluster” (M-DBP Cluster), to be published over

the next several years that are intended to control microbial pathogens while minimizing the public health

risks of disinfectants and disinfection byproducts (DBPs). The IESWTR is designed to address the health

risks from microbial contaminants without significantly increasing the potential risks from chemical

contaminants. This rule was published concurrently with the Stage 1 Disinfectants/Disinfection Byproducts

Rule (Stage 1 DBPR), which addresses control of disinfectants and their byproducts.

Background

The 1974 Safe Drinking Water Act (SDWA) called for EPA to regulate drinking water by creating the

national interim primary drinking water regulations (NIPDWR). In 1979, the first interim standard

addressing DBPs was set for total trihalomethanes (TTHMs), a group of four volatile organic chemicals

which form when disinfectants react with natural organic matter in the water. 

Although SDWA was amended slightly in 1977, 1979, and 1980, the most significant changes to the 1974

law occurred when SDWA was reauthorized in 1986. Disease-causing microbial contamination had not been

sufficiently controlled under the original Act. To safeguard public health, the 1986 Amendments required

EPA to set health goals, or maximum contaminant level goals (MCLGs) and maximum contaminant levels

(MCLs) for 83 named contaminants. EPA was also required to establish regulations within certain time

frames, require disinfection of all public water supplies, specify filtration requirements for nearly all water

systems that draw their water from surface sources, and develop additional programs to protect ground

water supplies.

In 1989, EPA issued two important National Primary Drinking Water Regulations (NPDWR): The Total

Coliform Rule (TCR) (40 CFR 141.21) and the Surface Water Treatment Rule (SWTR) (40 CFR 141

Subpart H). The TCR and SWTR provide the foundation for the M-DBP Cluster and are summarized

below.

The TCR covers all public water systems. Since coliforms are easily detected in water, they are used to

indicate a water system’s vulnerability to pathogens in the water. In the TCR, EPA set a MCLG of zero for

total coliforms. EPA also set a MCL for total coliforms. If more than 5.0 percent of the samples contain

coliforms within a month, water system operators must report this violation to the state and the public. In

addition, sanitary surveys are required every five or ten years (depending on the quality of the source water)

for every system that collects fewer than five samples per month (typically systems that serve less than

4,100 people).

EPA issued the SWTR in response to Congress’ mandate requiring disinfection, and where necessary,

filtration of systems that draw their water from surface sources before distribution. The SWTR applies to all

systems that use surface water or ground water under the direct influence of surface water (GWUDI). The

rule sets MCLGs for Legionella, Giardia lamblia, and viruses at zero since any exposure to these

contaminants presents some level of health risk. 
June 2001 I-4 IESWTR Implementation Guidance

Specifically, the rule requires that a surface water system have sufficient treatment to reduce the source

water concentration of Giardia lamblia and viruses by at least 99.9 percent (3 log) and 99.99 percent (4

log), respectively. A detectable disinfection residual must be maintained throughout the entire distribution

system. For systems that filter, the adequacy of the filtration process is determined by measuring the

turbidity of the treated water since high levels of turbidity often indicate that the filtration process is not

working properly. The goal of the SWTR is to reduce risk to less than one infection per year per 10,000

people. However, the SWTR does not account for systems with high pathogen concentrations that, when

treated at the levels required under the rule, still may not meet this health goal, and the rule does not

specifically control for the protozoan Cryptosporidium.

In 1990, EPA’s Science Advisory Board, an independent panel of experts established by Congress, cited

drinking water contamination as one of the most important environmental risks and indicated that diseasecausing microbial contaminants (i.e., bacteria, protozoa, and viruses) are probably the greatest remaining

health-risk management challenge for drinking water suppliers. Data from the Centers for Disease Control

(CDC) confirm this concern and indicate that between 1980 and 1994, 379 waterborne disease outbreaks

were reported, with over 500,000 cases of disease. During this period, a number of agents were implicated

as the cause, including protozoa, viruses, bacteria, and several chemicals. Most of the cases (but not the

outbreaks) were associated with surface water, including a single outbreak of cryptosporidiosis in Milwaukee

(over 400,000 cases).

In response to these findings, the SDWA was further amended in 1996 to improve public health protection

by incorporating new data on the adverse health effects of contaminants, the occurrence of contaminants in

public water systems, and the estimated reduction in health risks that would result from further regulation.

The Act also increased scientific research requirements and emphasized cost-benefit analyses in the

regulatory decision process. 

Based on prevailing scientific data, the M-DBP Cluster is intended to control microbial pathogens while

minimizing the public health risk from disinfectants and DBPs. Since multiple threats require multiple

barriers, the IESWTR and Stage 1 DBPR expand on the foundation of the TCR, SWTR, and TTHM

standards to target health risk outliers unaddressed by prior regulations.

The IESWTR builds on the SWTR by adding protection from Cryptosporidium through strengthened

combined filter effluent turbidity performance standards and individual filter turbidity provisions for filtered

systems that serve greater than 10,000 people using conventional and direct filtration. For unfiltered

systems, Cyptosporidium must be included in the watershed control requirements. In addition, the

IESWTR builds on the TCR by requiring sanitary surveys for all public water systems using surface water

and ground water under the direct influence of surface water. The IESWTR also requires covers for all new

finished water storage facilities and includes disinfection benchmark provisions to ensure continued levels of

microbial protection while taking the necessary steps to comply with the DBP standards. Collectively, the

SWTR and IESWTR place stringent treatment requirements on systems using surface water as a source.

By building on the foundation set forth by the original SDWA, the quality of drinking water has improved

and public health protection has increased. The IESWTR and Stage 1 DBP Rules are part of a series of

rules designed to expand on the foundation of prior rulemaking efforts. By encompassing previously

unaddressed health risks from microbials and disinfection byproducts, the M-DBP Cluster continues to

maximize drinking water quality and public health protection.
IESWTR Implementation Guidance I-5 June 2001

Development of the IESWTR

The new rules are a product of 6 years of collaboration among the water supply industry, environmental and

public health groups, and local, state, and federal governments. EPA first launched a rule-making process in

1992 and convened a Regulatory Negotiation (RegNeg) Advisory Committee under the Federal Advisory

Committees Act (FACA), representing a range of stakeholders affected by possible regulation. The 1996

SDWA Amendments required EPA to develop rules to balance the risks between microbial pathogens and

disinfection byproducts. 

In 1997, a similar FACA process was implemented with the Microbial-Disinfectants/Disinfection Byproducts

(M-DBP) Advisory Committee. The M-DBP Committee convened to collect, share, and analyze new

information available since 1994, review previous assumptions made during the RegNeg process, as well as

build consensus on the regulatory implications of this new information. Negotiations resulted in the following

three proposals:

C A staged approach to regulation of DBPs (referred to as the Stage 1 and Stage 2 DBPRs)

incorporating Maximum Contaminant Levels (MCLs), Maximum Residual Disinfectant

Levels (MRDLs), and treatment technique requirements;

C A companion Interim Enhanced Surface Water Treatment Rule (IESWTR) designed to

improve control of microbial pathogens and prevent inadvertent reductions in microbial

safety as a result of DBP control efforts; and,

C An Information Collection Rule (ICR) to collect information necessary to reduce many key

uncertainties prior to subsequent negotiations for the Stage 2 DBPR.

Benefits of the IESWTR

The IESWTR will improve public health by increasing the level of protection from exposure to

Cryptosporidium and other pathogens in drinking water supplies through improvements in filtration at water

systems. According to the risk assessment performed for the Regulatory Impact Analysis, the IESWTR

decreases the likelihood of endemic illness (constant, low-level presence of a disease or infection) from

Cryptosporidium by 110,000 to 463,000 cases annually. Based on these values, the estimated annual

benefits of reducing the illness range from $0.263 billion to $1.240 billion per year. This calculation is based

on a valuation of $2,000 per incidence of cryptosporidiosis prevented. The IESWTR will also reduce the

risk of more severe health impacts on sensitive populations, including the risk of mortality. Additionally, the

IESWTR will reduce the likelihood of outbreaks of cryptosporidiosis and its associated costs by providing a

larger margin of safety against such outbreaks in some systems.

Applicability and Compliance Dates

The IESWTR applies to public water systems (PWSs) that use surface water or ground water under the

direct influence of surface water (GWUDI) as a source and serve 10,000 or more people. Additionally, it

establishes a schedule by which states are required to conduct sanitary surveys for all surface water and

GWUDI PWSs. 

Systems must comply with the turbidity and monitoring requirements, the primary requirements of the

IESWTR, no later than January 1, 2002. However, PWSs with elevated levels of DBPs (Total
June 2001 I-6 IESWTR Implementation Guidance

Trihalomethanes—TTHM; and five haloacetic acids—HAA5) are required to develop an evaluation of their

existing disinfection practices—a disinfection profile—beginning no later than March 31, 2000. 

Requirements of the Rule: Public Water Systems 

Disinfection profiling and benchmarking

Surface water or GWUDI systems having average annual TTHM $ 0.064 mg/L or annual average 

HAA5 $ 0.048 mg/L as a result of data or specific monitoring conducted by March 31, 2000 must develop

a disinfection profile. The disinfection profile is a compilation of daily inactivation of Giardia (and in some

cases, viruses) based on daily criteria (i.e., disinfectant residual, pH, temperature, and peak flow) that affect

the efficacy of the disinfection process (microbial inactivation potential) collected over the period of 1 year.

Systems may also use existing operational data in conjunction with daily criteria or three years of existing

operational data to create a multi-year profile, if approved by the state. From the disinfection profile, the

PWS calculates the average microbial inactivation for each month, and the lowest monthly average

inactivation for the year becomes the disinfection benchmark. For systems creating a multi-year profile, the

disinfection benchmark is the average of the lowest monthly average values.

The purpose of these provisions is to provide a process whereby a PWS and the state, working together,

assure that there will be no significant reduction in microbial protection as the result of disinfection practice

modifications designed to meet the more restrictive maximum contaminant levels (MCLs) for DBPs

established in the Stage 1 DBPR. If a PWS required to develop disinfection profiles subsequently wishes to

modify its disinfection practices to meet the new MCLs, it must establish the disinfection benchmark and

consult with the state prior to implementing such modifications. In addition, PWSs must keep the

disinfection profile on file for the state to review during their sanitary surveys.

Cryptosporidium

The IESWTR sets a maximum contaminant level goal (MCLG) of zero for the protozoan Cryptosporidium.

It also establishes a requirement for 2-log removal of Cryptosporidium for systems that must filter under the

SWTR. Systems that use conventional or direct filtration are assumed to meet this requirement if they are in

compliance with the strengthened turbidity performance standards for combined filter effluent in the

IESWTR (discussed below). Systems that use slow sand or diatomaceous earth filtration are assumed to

meet the 2-log removal requirement if they are in compliance with the existing turbidity performance

standards under the SWTR. 

The IESWTR also extends the existing watershed control requirements for unfiltered systems to include the

control of potential sources of Cryptosporidium. Such sources must be included in an unfiltered system’s

watershed control plan.

Strengthened turbidity requirements

The IESWTR includes a series of requirements related to turbidity. These requirements strengthen current

SWTR requirements for combined filter effluent for systems that use conventional or direct filtration. The

turbidity level of a system’s combined filtered water at each plant must be less than or equal to 0.3

nephelometric turbidity units (NTUs) in at least 95 percent of the measurements taken each month, and the

turbidity level of a system’s combined filtered water must at no time exceed 1 NTU (under the SWTR,

these turbidity requirements are 0.5 NTU and 5 NTU, respectively).
IESWTR Implementation Guidance I-7 June 2001

Individual filter monitoring requirements

The IESWTR introduces continuous turbidity monitoring for individual filters. The rule requires that surface

water and GWUDI systems that use conventional or direct filtration must conduct continuous turbidity

monitoring (every 15 minutes) on the effluent of each individual filter. PWSs must report instances of poor

filter performance to the state, and, based on performance triggers, must take prescribed actions to identify

and correct the cause(s).

Uncovered finished water storage facilities

The rule prohibits building any uncovered finished water storage facility (reservoir, holding tank, or other

storage facility) for which construction begins after February 16, 1999 (60 days after publication).

Public water system recordkeeping and reporting requirements

The IESWTR requires PWSs to submit combined filter effluent monitoring and compliance data and report

that they have conducted individual filter turbidity monitoring to states within 10 days after the end of each

month the system serves water to the public. Additionally, PWSs must report to the state if certain

individual filter monitoring trigger levels are exceeded. In this case, systems must report turbidity

measurements and report that filter profiles, filter self-assessments, or comprehensive performance

evaluation (CPE) reports have been produced or conducted when instances of poor filter performance occur

or persist based on monitoring of individual filter performance. Systems must maintain the results of

individual filter monitoring for at least three years.

Requirements of the Rule: States or Other Primacy Agents 

Sanitary surveys

The IESWTR requires that the state conduct sanitary surveys for all PWSs using surface water or GWUDI,

regardless of the population the PWS serves, no less frequently than every 3 years for community water

systems and every 5 years for noncommunity systems. For community water systems determined by the

state in previous sanitary surveys to have “outstanding performance,” successive sanitary surveys may be

conducted at up to 5-year intervals. As part of the eight required sanitary survey components, the state also

must review the disinfection profile as part of the sanitary survey.

States must have rules or other authority to ensure that a PWS responds to any “significant deficiencies”

revealed during its survey within 45 days, indicating how and on what schedule the system will address the

deficiencies noted in the survey. States must also have rules or other authority to ensure that facilities take

the steps necessary to address significant deficiencies identified in the survey report that are within the

control of the PWS and its governing body.

State primacy, recordkeeping, and reporting requirements

In order to receive primacy for the IESWTR, states must adopt regulations no less stringent than this rule.

In addition, states are required to explain, through responses to special primacy requirements, how they will

implement the key provisions in the rule. States must have rules or other authority to require PWSs to

respond to significant deficiencies uncovered in a sanitary survey, to conduct a Composite Correction
June 2001 I-8 IESWTR Implementation Guidance

Program (CCP), and to assure that PWSs implement any follow-up recommendations that result from the

CCP. States must submit revisions to their programs, regulations, or authorities no later than December 16,

2000 (2 years after rule publication), although states can request an extension of up to 2 years (December

16, 2002).

States must keep records of PWS turbidity measurements, PWSs required to do filter self-assessment

reports, CPEs, CCPs, PWSs consulting with the state concerning modifications to disinfection practices, and

decisions for PWSs using alternative filtration technology.

More information can be obtained from:

L The Interim Enhanced Surface Water Treatment Rule 

63 FR 69478 (December 16, 1998)

www.epa.gov/OGWDW/mdbp/ieswtrfr.html

L The Interim Enhanced Surface Water Treatment Rule:

Technical Corrections

66 FR 3770 (January 16, 2001)

www.epa.gov/safewater/mdbp/iesfr.html

L The EPA Safe Drinking Water Hotline, Telephone:

1.800.426.4791
IESWTR Implementation Guidance I-9 June 2001

I-B. Key Dates for the IESWTR

The compliance date for the Interim Enhanced Surface Water Treatment Rule (IESWTR) is January 1,

2002. Several provisions, including disinfection profiling and benchmarking and restrictions on uncovered

finished water storage facilities, however, will require compliance before the primary compliance date. The

timetable for the IESWTR is presented in Table I-1.

Table I-1: Timetable for the IESWTR Requirements

Date IESWTR Requirement

December 16, 1998 Rule is published in Federal Register [63 FR 1 69478].

February 16, 1999 60-day legal challenge period ends.

February 16, 1999 Construction of uncovered finished water storage facilities is prohibited [40 CFR

141.170(c)].

March 16, 1999 After this date, TTHM and HAA5 monitoring must begin for systems that do not have

ICR or occurrence data and wish to determine if they must develop a disinfection

profile [40 CFR 141.172(a)(2)(iii)].

April 16, 1999 Systems that have 4 consecutive quarters of HAA5 occurrence data that meet the

TTHM monitoring requirements must submit those data to the state to determine if

they must develop a disinfection profile [40 CFR 141.172(a)(5)(ii)].

December 31, 1999 TTHM and HAA5 data are due for those systems that collected data under the ICR to

determine if they must develop a disinfection profile [40 CFR 141.172(a)(5)(i)].

December 31, 1999 Systems that elect to profile without conducting 4 quarters of TTHM and HAA5

monitoring must notify the state of their election [40 CFR 141.172(a)(5)(iv)].

December 31, 1999 Systems that wish to request state approval of “a more representative annual data set”

than the ICR data set to determine if they must develop a disinfection profile must do

so in writing [40 CFR 141.172(a)(5)(v)]. 

March 31, 2000 TTHM and HAA5 monitoring must be complete for systems determining if they must

develop a disinfection profile [40 CFR 141.172(a)(2)(iii)(A)].

March 31, 2000 If system is using 3 years of existing operational data to develop the disinfection

profile, the profile generated from these data and a request for state approval must be

submitted [40 CFR 141.172(b)(3)(i)].

April 1, 2000 Systems determining if they must develop a disinfection profile must submit their

TTHM and HAA5 data to the state [40 CFR 141.172(a)(5)(iii)].

April 1, 2000 Systems must begin developing a disinfection profile if either their annual average

TTHM $ 0.064 mg/L or their annual average HAA5 $ 0.048 mg/L [40 CFR

141.172(b)(2)].

December 16, 2000 Final primacy applications must be submitted to EPA unless granted an extension [40

CFR 142.12(b)(1)]

March 31, 2001 Disinfection profile is complete [40 CFR 141.172(b)(2)].

March 31, 2001 After this date, systems that were required to develop a disinfection profile that wish to

make a significant change to their disinfection practice must first calculate a

disinfection benchmark and consult with the state [40 CFR 141.172(c)].
Date IESWTR Requirement

June 2001 I-10 IESWTR Implementation Guidance

December 31, 2001 Systems that are not required to filter must comply with the requirements for TTHM in

§141.12 and §141.30 until this date. After this date, systems must comply with the

requirements in Subpart L for TTHM, HAA5, bromate, chlorite, chlorine, chloramines,

and chlorine dioxide [40 CFR 141.71(b)(6)].

December 31, 2001 Systems that do not meet all of the criteria for avoiding filtration and use

conventional/direct filtration must meet the turbidity requirements of the rule [0.3

NTU CFE (Combined Filter Effluent) 95 percent of the time, at no time exceed 1 NTU]

[40 CFR 141.173]. 

December 31, 2001 Alternative technologies for systems that serve at least 10,000 people must remove 99

percent of Cryptosporidium oocysts, and the state must establish alternative turbidity

performance standards that must be met 95 percent of the time and a maximum [40

CFR 141.173(b)].

January 1, 2002 Systems must comply with the reporting and recordkeeping requirements of §141.175,

including turbidity exceptions reporting. Systems must, when appropriate:

• Produce filter profiles or identify obvious reason for poor filter performance.

• Report profile has been produced or identify obvious reason for poor filter

performance.

• Conduct filter self-assessments.

• Have 3rd party CPEs performed.

December 16, 2002 Final primacy revisions applications with approved extensions must be submitted to

EPA [40 CFR 142.12(b)(2)].

December 2004 State must have first round of sanitary surveys completed for Subpart H CWSs [40 CFR

142.16(b)(3)(i)].

December 2006 State must have first round of sanitary surveys completed for Subpart H NCWSs [40

CFR 142.16(b)(3)(i)].
Section II. 

SDWIS Reporting and SNC

Definitions
June 2001 II-2 IESWTR Implementation Guidance

This page is left intentionally blank.
IESWTR Implementation Guidance II-3 June 2001

II-A. Safe Drinking Water Information System (SDWIS)

Reporting Under the IESWTR

SDWIS/FED (Safe Drinking Water Information System/Federal version) is an EPA national database

storing routine information about the nation's drinking water. Designed to replace the system known as

FRDS (Federal Reporting Data System), SDWIS/FED stores the information EPA needs to monitor

approximately 175,000 public water systems. 

States supervise the drinking water systems within their jurisdictions to ensure that each public water system

meets state and EPA standards for safe drinking water. The Safe Drinking Water Act (SDWA) requires

states to report drinking water information periodically to EPA; this information is maintained in

SDWIS/FED. 

States report the following information to EPA: 

• Basic information on each water system, including: name, ID number, number of people served,

type of system (year-round or seasonal), and source of water (ground water or surface water) 

• Violation information for each water system: whether it has followed established monitoring and

reporting schedules, complied with mandated treatment techniques, or violated any Maximum

Contaminant Levels (MCLs) 

• Enforcement information: what actions states have taken to ensure that drinking water systems

return to compliance if they are in violation of a drinking water regulation 

• Sampling results for unregulated contaminants and for regulated contaminants when the monitoring

results exceed the MCL 

EPA uses this information to determine if and when it needs to take action against non-compliant systems,

oversee state drinking water programs, track contaminant levels, respond to public inquiries, and prepare

national reports. EPA also uses this information to evaluate the effectiveness of its programs and

regulations, and to determine whether new regulations are needed to further protect public health. 

II-A.1 Federally Reported Violations

Under SDWIS/FED reporting, states only report when violations occur. In the interest of reducing the

reporting burden on states, EPA has limited the number and type of violations to be reported to

SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any

violation of the rule, whether included in the accompanying table or not, is a basis for a state or federal

enforcement action.

Table II-1 summarizes the violation and contaminant codes that will be used to report violations of the

IESWTR to SDWIS/FED. 
1

 Flag used to denote major or minor

June 2001 II-4 IESWTR Implementation Guidance

Table II-1: SDWIS/FED Codes for Federal Reporting Under the IESWTR

Violation

Code 

Contaminant

Code

Treatment Technique (TT) Violations

37 0300 Failure to profile or consult w/state (disinfection changes)

43 0300 Combined filter effluent exceeds 1 NTU/state-set maximum requirements

44 0300 More than 5% of monthly combined filter effluent samples exceed 0.3

NTU/state-set maximum requirements

47 0300 Construction of an uncovered finished water storage facility

Inventory

Code

0300 Failure to meet Cryptosporidium site specific conditions (unfiltered systems)

Monitoring and Reporting (M/R) Violations

29 0300 Major: Failure to conduct follow-up activities triggered by individual filter

turbidity exceedances.

381 0300 Major: Failure to collect and report 90% of required combined filter effluent

turbidity samples

Major: Failure to report all individual filter monitoring has been conducted

Major: Failure to report combined filter effluent exceedances by the end of the

next business day

Minor: Any other failure to monitor or report

Recordkeeping Violations

09 0300 Failure to maintain the results of individual filter monitoring for at least 3 years

Public Notification (PN) Violation*

06 0300 Failure to notify public after a violation

* The revised PN rule (65 FR 25981) is effective May 6, 2002 and will supercede the PN violation listed above.

Table II-2 contains the federally reportable violations for the IESWTR in more detail. These violations are

listed by contaminant or requirement and violation type. The table includes the SDWIS/FED reporting

codes, the regulatory citation, system type affected, a detailed description of the violation, and the initial

compliance date. This table will allow a user to better understand violations listed in SDWIS. For more

information on how to report IESWTR violations to SDWIS, please refer to the State Reporting Guidance

for the Interim Enhanced Surface Water Treatment Rule which will be available at

www.epa.gov/safewater/mdbp/implement.html in fall 2001.
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

IESWTR Implementation Guidance II-5 June 2001

Table II-2: Federally Reported Violations for the IESWTR

Treatment Technique Violation

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size and

Type Affected Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

37/0300 Disinfection and

Consultation 

§141.172(b) and (c) TT All Subpart H

systems serving

at least 10,000

people

Failure to consult with the state before making a

significant change to a disinfection practice if

required to develop a disinfection profile

January 1,

2002

43/0300 Filtration §141.173(a)(2) and (b) TT Subpart H

systems serving $

10,000 using

conventional or

direct filtration

Subpart H

systems serving $

10,000 using

alternative

filtration

technologies 

Failure to achieve combined filter effluent turbidity

level that at no time exceeds 1 NTU if PWS uses

conventional or direct filtration 

or 

exceedance of the state-set maximum turbidity

performance requirements for systems using

alternative filtration technologies

January 1,

2002
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

Treatment Technique Violation

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size and

Type Affected Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

June 2001 II-6 IESWTR Implementation Guidance

44/0300 Filtration §141.173(a)(1) TT Subpart H

systems serving $

10,000 using

conventional or

direct filtration

Subpart H

systems serving $

10,000 using

alternative

filtration

technologies 

Failure to achieve combined filter effluent turbidity

level of 0.3 NTU in 95 percent of monthly

measurements if PWS uses conventional or direct

filtration 

or 

failure to meet the state-set turbidity performance

requirements in 95% of monthly measurements for

systems using alternative filtration technologies

January 1,

2002

47/0300 Finished Water

Storage

Facilities

§141.170(c) TT All Subpart H

systems serving

at least 10,000

people

Systems are not allowed to start construction of any

uncovered finished water storage facility (reservoir,

holding tank, or other storage facility)

February 16,

1999

Inventory

Code/0300

Cryptosporidiu

m

§141.171 TT All unfiltered

Subpart H

systems serving

at least 10,000

people

Failure to meet Cryptosporidium site specific

condition requirements - system must install

filtration within 18 months. Do not report a

violation, but change the inventory record/code from

“unfiltered avoiding” to “unfiltered required to

filter”. Report a 42 code violation if filtration has

not been installed after 18 months.

January 1,

2002
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

IESWTR Implementation Guidance II-7 June 2001

Monitoring and Reporting Violations

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size

and Type

Affected

Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

29/0300 Filtration -

Response to

Individual Filter

Trigger

§141.175(b)(2) M/R Major Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to produce and/or report to the state an

individual filter profile within 7 days of a turbidity

exceedance (> 0.5 NTU in 2 consecutive

measurements taken 15 minutes apart after the first 4

hours of operation after filter backwash or otherwise

taken offline) if the PWS is not able to identify an

obvious reason for abnormal filter performance

January 1, 2002

29/0300 Filtration -

Response to

Individual Filter

Trigger

§141.175(b)(1) M/R Major Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to produce and/or report to the state an

individual filter profile within 7 days of a turbidity

exceedance (> 1.0 NTU in 2 consecutive

measurements taken 15 minutes apart) if the PWS is

not able to identify an obvious reason for abnormal

filter performance

January 1, 2002

29/0300 Filtration -

Response to

Individual Filter

Trigger

§141.175(b)(3) M/R Major Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to conduct and/or report to the state a selfassessment of an individual filter within 14 days of a

turbidity exceedance (> 1.0 NTU in 2 consecutive

measurements taken 15 minutes apart in each of 3

consecutive months)

January 1, 2002

29/0300 Filtration -

Response to

Individual Filter

Trigger

§141.175(b)(4) M/R Major Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to have a comprehensive performance

evaluation conducted by the state or a third party no

later than 30 days after a turbidity exceedance (> 2.0

NTU in 2 consecutive measurements taken 15 minutes

apart in 2 consecutive months) and have the evaluation

completed and submitted to the state no later than 90

days following the exceedance

January 1, 2002
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

Monitoring and Reporting Violations

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size

and Type

Affected

Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

June 2001 II-8 IESWTR Implementation Guidance

38/0300 Filtration/

combined filter

effluent

§141.175(a)

§141.74

M/R Major

Failure to

collect and

report at least

90 % of

required

samples.

Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to sample combined filter effluent for

turbidity at required frequency using required

collection and analytical methods and report the

following within 10 days after the end of each month

the PWS serves water to the public: 

1. total number of samples taken, the number and

percentage of samples less than or equal to the limits

specified in §141.73 or §141.173; and/or

2. date and level of any measurements over 1 NTU for

conventional or direct filtration or which exceed the

maximum level set by the state for alternative

filtration technologies

January 1, 2002

M/R Minor

Any other

failure to

monitor or

report.

38/0300 Filtration §141.175(b) M/R Major Subpart H

systems

serving $

10,000 using

conventional or

direct filtration

Failure to report that the system has conducted all

individual filter monitoring to the state within 10 days

after the end of each month

January 1, 2002
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

Monitoring and Reporting Violations

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size

and Type

Affected

Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

IESWTR Implementation Guidance II-9 June 2001

38/0300 Filtration §141.175(c) M/R Major All Subpart H

systems

serving at least

10,000 people

Failure to report that the system has exceeded 1 NTU

in representative samples by the end of the next

business day if the PWS uses conventional filtration

treatment or direct filtration, or

Failure to report that the system has exceeded the

maximum level set by the state under §141.173(b) for

filtration technologies other that conventional

filtration, direction filtration, slow sand, or

diatomaceous earth filtration in representative

samples by the end of the next business day.

January 1, 2002
This chart contains the federally reportable violations for the IESWTR. In the interest of reducing the reporting burden on states, EPA has limited the number and type of

violations to be reported to SDWIS/FED. However, PWSs must still keep records and report all required information to the state. Any violation of the rule is a basis for a state

or federal enforcement action.

June 2001 II-10 IESWTR Implementation Guidance

Recordkeeping Violations

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size

and Type

Affected

Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

09/0300 Filtration §141.175(b) Recordkeeping Subpart H

systems serving

$ 10,000 using

conventional or

direct filtration

Failure to maintain the results of individual filter

monitoring for at least 3 years, documenting that the

system has collected and recorded individual filter

results every 15 minutes

January 1,

2002

Public Notification Violations (Note: The revised PN rule supercedes §141.32)

SDWIS

Reporting

Code

Regulated

Contaminant/

Requirement

Citation Violation

Type

System Size and

Type Affected Violation

Initial

Compliance

Date

1 2 3 4 5 6 7

06/0300 Filtration and

Disinfection

§141.32 PN All Subpart H

serving at least

10,000 people

Failure to notify public and use approved public

notification language when there is a violation of the

treatment technique and/or monitoring requirements

for filtration and disinfection in Subpart H or 

Subpart P

January 1,

2002
IESWTR Implementation Guidance II-11 June 2001

II-B. SNC Definitions for the IESWTR

Significant non-compliers (SNCs) are community, non-transient non-community and transient noncommunity water systems that have more serious, frequent, or persistent violations. The criteria which

designate a system as a SNC vary by contaminant. Once a system is designated as a SNC, it is subject to

EPA’s timely and appropriate policy. SNCs that have not returned to compliance or are not addressed

timely and appropriately are called Exceptions. Timeliness for SNCs is eight months after the system

became a SNC. (Two months for the state to determine, and become aware of, the system’s SNC status

and six months in which to complete the follow-up/enforcement action). The types of actions considered

appropriate include the issuance of a formal state or federal administrative or compliance order, a civil or

criminal referral to state Attorney General or Department of Justice, or state bilateral compliance agreement

signed by both the state and the violator. The following are SNC definitions for the IESWTR. 

NOTE: SNC definitions for the Surface Water Treatment Rule continue to remain in effect.

UNFILTERED AVOIDING FILTRATION

C Systems which fail avoidance criteria must filter. See 6/27/90 Surface Water Treatment Rule

Implementation Manual. Systems become an SNC if filtration is not installed within 18 months of

any failure of the avoidance criteria.

C A system that has three (3) or more Major M/R violations in any 12 consecutive months.

C A system that has a combination of five (5) or more Major M/R violations and Minor M/R

violations in any 12 consecutive months.

FILTERED

• A system that has four (4) or more TT violations in any 12 consecutive months.

C A system that has a combination of six (6) or more TT violations and Major M/R violations in any

12 consecutive months.

C A system that has a combination of ten (10) or more TT violations, Major M/R violations, and

Minor M/R violations in any 12 consecutive months.

DISINFECTION PROFILING (if required)

C Failure to consult with the state before making a significant disinfection change if required to

develop a disinfection profile.

UNCOVERED RESERVOIRS

C Beginning construction of any uncovered finished water storage facility after February 16, 1999.
June 2001 II-12 IESWTR Implementation Guidance

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Section III.

State Primacy Revision

Applications
June 2001 III-2 IESWTR Implementation Guidance

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IESWTR Implementation Guidance III-3 June 2001

Changes to the Primacy Revision Process

40 CFR 142 sets out requirements for states to obtain and/or retain primary enforcement responsibility

(primacy) for the Public Water System Supervision (PWSS) program as authorized by §1413 of the Safe

Drinking Water Act (SDWA). The 1996 SDWA Amendments create an additional requirement and modify

the process for states to obtain and/or retain primacy. On April 28, 1998, EPA promulgated the Primacy

Rule to reflect these statutory changes (63 FR 23361).

For consistency with the Amendments to §1413, the Primacy Rule makes the following changes to the

existing regulations in 40 CFR 142:

1) Administrative Penalty Authority—As a condition of primacy, states must now have

administrative penalty authority for all violations of their approved primacy program, unless

prohibited by the states’ constitution. This encompasses applicable requirements in 40 CFR 141 and

142 including, but not limited to, National Primary Drinking Water Regulations, variances and

exemptions, if applicable, and public notification requirements.

2) Interim Primacy—The Primacy Rule also codifies the new process which grants primary

enforcement authority to states while their applications to modify their primacy programs are under

review (interim primacy). New section 142.12(e) explains that any state already having primacy for

all existing national primary drinking water regulations in effect when a new regulation is

promulgated is considered to have interim primacy for a new or revised regulation, once it has

submitted a complete and final primacy revision application. This interim enforcement authority

begins on the date of submission of a complete and final primacy revision application or the

effective date of the new or revised state regulation, whichever is later, and ends when EPA makes

a final determination.

3) Time increases for rule adoptions—The rule also increases the time for a state to adopt new or

revised federal regulations from 18 months to 2 years.

4) Examples of emergencies—Finally, the Primacy Rule adds examples of circumstances that require

an emergency plan for the provision of safe drinking water. Emergencies include earthquakes,

floods, hurricanes, and other natural disasters.

For consistency with the Amendments to §1401(4), the Primacy Rule expands the definition of a public

water system (PWS) to include not only systems which provide water for human consumption through

pipes, but also systems which provide water for human consumption through “other constructed

conveyances.”

III-A. State Primacy Program Revision

Pursuant to §142.12, Revision of State Programs, complete and final requests for approval of program

revisions to adopt new or revised EPA regulations must be submitted to the Administrator no later than 2

years after promulgation of the new or revised federal regulations (see Table III-1). Until those applications

are approved, EPA Regions have responsibility for directly implementing the IESWTR. The state and EPA

can agree to implement the rule together during this period. However, if a state is eligible for interim

primacy, once it submits a complete and final revision package, it will have full implementation and

enforcement authority. A state may be granted additional time, up to two years, to submit its application

package. During this period, an extension agreement outlining the state’s and EPA’s responsibilities is

required. 
June 2001 III-4 IESWTR Implementation Guidance

Table III-1: State Rule Implementation and Revision Timetable

EPA/State Action Time Frame

IESWTR published by EPA December 16, 1998

State and Region establish a process and agree upon a schedule for application

review and approval

May 1999

State, at its option, submits draft program revision package including:

Preliminary Approval Request

Draft State Regulations and/or Statutes

Regulation Crosswalk

September 1999

(Suggested)

Regional (and Headquarters if necessary) review of draft Completed within 90 days

of state submittal of Draft

State submits final program revision package including:

Adopted State Regulations

Regulation Crosswalk

40 CFR 142.10 Primacy Update Checklist

40 CFR 142.14 and 142.15 Reporting and Recordkeeping

40 CFR 142.16 Special Primacy Requirements

Attorney General’s Enforceability Certification

By September 16, 2000*

EPA final review and determination:

Regional review (program and ORC)

Headquarters concurrence and waivers (OGWDW, OECA, OGC)

Public Notice

Opportunity for hearing

EPA’s Determination

Completed within 90 days

of state submittal of final

45 days Region

45 days Headquarters 

Rule Effective Date January 1, 2002

* EPA suggests submitting an application by September 2000, to ensure timely approval. EPA regulations allow

until December 16, 2000 for this submittal. An extension of up to 2 additional years may be requested by the state.
IESWTR Implementation Guidance III-5 June 2001

III-A.1 The Revision Process

The approval of state program revisions is recommended to be a two-step process comprised of submission

of a draft request (optional) and then submission of a complete and final request for program approval.

Figure III-1 diagrams these processes and their timing.

Draft Request—At the state’s option, it may submit a draft request for EPA review and tentative

determination. The request should contain drafts of all required primacy application materials. A draft

request should be submitted by 9 months after rule promulgation. EPA will make a tentative determination

on whether the state program meets the applicable requirements. The tentative determination should be

made within 90 days.

Complete and Final Request—This submission must be in accordance with §142.12(c)(1) and (2) and

include the Attorney General’s statement. If the state has submitted a draft request for EPA review the state

must also address comments and/or program deficiencies identified in the tentative determination in their

final submission. Regions should make states aware that submission of only a final request may make it

more difficult for the states to address any necessary changes within the allowable time for state rule

adoption.

EPA requests that states submit their complete and final revision package within 21 months of rule

promulgation. This will ensure that states will have interim primacy within 24 months and will prevent states

from becoming backlogged with revision applications to adopt future federal requirements. 

The state and Region should agree to a plan and timetable for submitting the state primacy revision

application as soon as possible after rule promulgation—ideally within 5 months of promulgation.
June 2001 III-6 IESWTR Implementation Guidance

EPA Promulgates

IESWTR

State Submits Draft

Primacy Revision 

Application to EPA

§142.12(d)(1)(i)

Timeline

Start

9 Months Later

Establish Process and 

Tentative Schedule for 

State Rule Approval

May 1999

September 1999

EPA Review and

Tentative Determination

(within 90 days)

§142.12(d)(1)(ii)

State Submits 

Complete and Final 

Primacy Revision 

Application to EPA

§142.12(d)(2)(i)

EPA Review and 

Determination 

(within 90 days) 

§142.12(d)(3)

Request for

Extension 

§142.12(b)

Additional

Time

Given

21 Months Later

24 Months Later

September 2000

December 2000

Denied

Granted

5 Months Later

December 16, 1998

Figure III-1: Recommended Review Process for State Request for Approval of

Program Revisions
IESWTR Implementation Guidance III-7 June 2001

III-A.2 The Final Review Process

Once a state application is complete and final, EPA has a regulatory (and statutory) deadline of 90 days to

review and approve or disapprove of the revised program. The Offices of Ground Water and Drinking

Water (OGWDW) and Enforcement and Compliance Assurance (OECA) will conduct detailed reviews of

the first state package from each Region. The Region should submit their comments with the state’s

package for Headquarter’s review. Where the Region has identified all significant issues, OGWDW and

OECA will waive concurrence on all other state programs in that Region, although HQ will retain the option

to review additional state programs with cause. The Office of General Counsel (OGC) has delegated its

review and approval to the Office of Regional Counsel (ORC).

In order to meet the 90 day deadline for packages undergoing Headquarters’ review, the review period will

be equally split giving both the Regions and Headquarters 45 days to conduct their respective reviews. For

the first package in each Region, Regions should forward copies of the primacy revision applications and

their comments to the director of the Drinking Water Protection Division (DWPD) in OGWDW. The

DWPD Director will take the lead on the review process. OGWDW will provide OECA with a copy for

their concurrent review. OECA will concur on OGWDW approvals. 

III-B. State Primacy Program Revision Extensions (40 CFR

142.12(b))

III-B.1 The Extension Process

Under §142.12(b), states may request that the 2-year deadline for submitting the complete and final request

for EPA approval of program revisions be extended for up to 2 additional years in certain circumstances.

The extension request must be submitted to EPA within 2 years of the date that EPA published the

regulation. The Regional Administrator has been delegated authority to approve extension applications.

Headquarters concurrence on extensions is not required.

III-B.2 Criteria that an Extension Request Must Meet

For an extension to be granted under § 142.12(b), the state must demonstrate that it is requesting the

extension because it cannot meet the original deadline for reasons beyond its control, despite a good faith

effort to do so. A critical part of the extension application is the state’s proposed schedule for submission of

its complete and final request for approval of a revised primacy program. The application must also

demonstrate at least one of the following:

(i) That the state currently lacks the legislative or regulatory authority to enforce the new or revised

requirements; or,

(ii) That the state currently lacks the program capability adequate to implement the new or revised

requirements; or,

(iii) That the state is requesting the extension to group two or more program revisions in a single

legislative or regulatory action.

In addition, the state must be implementing the EPA requirements to be adopted in its program revision

within the scope of its current authority and capabilities.
June 2001 III-8 IESWTR Implementation Guidance

III-B.3 Conditions of the Extension

If an extension is granted, the Region and state will negotiate certain conditions that must be met during the

extension period. These conditions will be determined during the extension approval process and are decided

on a case-by-case basis. The conditions must be included in an extension agreement between the state and

the EPA Regional office. Appendix B contains a sample extension agreement. 

Conditions of an extension agreement may include:

C Informing PWSs of the new EPA (and upcoming state) requirements and that the Region

will be overseeing implementation of the requirements until they approve the state program

revisions or until the state submits a complete and final revision package if the state

qualifies for interim primacy;

C Collecting, storing and managing laboratory results, public notices, and other compliance

and operation data required by the EPA regulations; 

C Assisting the Region in the development of the technical aspects of enforcement actions and

conducting informal follow-up on violations (telephone calls, letters, etc.);

C Providing technical assistance to public water systems;

C For states whose request for an extension is based on a current lack of program capability

adequate to implement the new requirements, taking steps agreed to by the Region and the

state during the extension period to remedy the deficiency;

C Providing the Region with all the information required under §142.15 on state reporting.

Figure III-2 provides a checklist the Region can use to review state extensions.
IESWTR Implementation Guidance III-9 June 2001

Figure III-2: Extension Request Checklist

I. Reason for State Request

 Clustering of Program Revisions

 Statutory Barrier

 Regulatory Barrier

 Lack of Program Capability

 Insufficient Resources

 Funding Level

 Staffing

 Lack of Adequately Trained Staff

 Inadequate Procedures, Guidelines, and Policies

 Other 

II. Actions Taken by the State to Justify an Extension

Schedule Dates

(or attachments)

 Seeking Increases in Program Resources 

 Training Existing Personnel/Revising Training Programs 

 Revising State Regulations or Statutes 

 Developing Revised/New Procedures, Guidelines, Policies 

 Other 

 

III. Extension Decision

 Extension Request Approved Date: / / 

 Period of Extension Request: / / to / / 

 Extension Request Denied Date: / / 

 Reason Cited: 

IV. Conditions of the Extension

During the extension period the state will (check all that apply):

 Inform public water systems of the new requirements and the fact that EPA will be

overseeing their implementation until the state’s program is approved or submitted if state

qualifies for interim primacy

 Collect and store laboratory results and other compliance data

 Provide technical assistance to public water systems

 Provide EPA with the information required under section 142.15 of the primacy rule

 Other 
June 2001 III-10 IESWTR Implementation Guidance

III-C. State Primacy Package

The primacy revision application package should consist of the following sections:

III-C.1 Section I—The State Primacy Revision Checklist (40 CFR 142.10)

This section is a checklist of general primacy requirements, taken from 40 CFR 142.10, as shown in Table

III-2. In completing this checklist, the state must identify the program elements that it has revised in

response to new federal requirements. If an element has been revised the state should indicate a “Yes”

answer in the second column next to the list of program elements and should submit appropriate

documentation. For elements that need not be revised, the state need only list the citation and date of

adoption in the second column. During the application review process, EPA will insert findings and

comments in the third column.

Table III-2: State Primacy Revision Checklist

Required Program Elements Revision to State

Program

EPA

Findings/Comments

§142.10 Primary Enforcement

– Definition of Public Water System*

§142.10(a) Regulations No Less Stringent

§142.10(b)(1) Maintain Inventory

§142.10(b)(2) Sanitary Survey Program

§142.10(b)(3) Laboratory Certification Program 

§142.10(b)(4) Laboratory Capability

§142.10(b)(5) Plan Review Program

§142.10(b)(6)(i) Authority to apply regulations

§142.10(b)(6)(ii) Authority to sue in courts of competent

jurisdiction

§142.10(b)(6)(iii) Right of Entry

§142.10(b)(6)(iv) Authority to require records

§142.10(b)(6)(v) Authority to require public notification 

§142.10(b)(6)(vi) Authority to assess civil and criminal

penalties

§142.10(b)(6)(vii) Authority to require CWSs to provide CCRs

§142.10(c) Maintenance of Records

§142.10(d) Variance/Exemption Conditions (if

applicable)**

§142.10(e) Emergency Plans

§142.10(f) Administrative Penalty Authority*

* New requirement from the 1996 Amendments. Regulations published in the April 28, 1998 Federal Register.

** New regulations published in the August 14, 1998 Federal Register.
IESWTR Implementation Guidance III-11 June 2001

The 1996 SDWA Amendments include new provisions for PWS definition and administrative penalty

authority. States must adopt provisions at least as stringent as these new provisions, now codified at 40 CFR

142.2 and 142.10. Failure to revise primacy for these new provisions can affect primacy for the IESWTR.

However, states may still receive primacy for the IESWTR even if they have not yet revised their base

program to comply with the new statutory requirements provided that the time to adopt these requirements

(including the extension period if applicable) has not expired (April 2000 and April 2002 with extension). 

Rule Bundling—States may bundle the new PWS definition, administrative penalty authority, variance and

exemption requirements or any other drinking water regulation with the IESWTR primacy revision packages

so long as the submittal date (two years plus two year extension) has not lapsed. If states choose to bundle

these requirements, the state needs to include the text of the state regulation/statute. The Attorney General

statement should reference these new requirements. 

III-C.2 Section II—Text of the State’s Regulation (40 CFR 142.10)

Each primacy application package must include the text of the state regulation.

III-C.3 Section III—Primacy Revision Crosswalk

The Primacy Revision Crosswalk, found in Appendix A, should be completed by states in order to identify

state statutory or regulatory provisions that correspond to each federal requirement. If the state’s provisions

differ from federal requirements, the state should explain how its requirements are “no less stringent.” For

the “early requirements” of the IESWTR that will be completed prior to state rule adoption, a state

regulation that does not include these requirements will still be considered as stringent as the federal

requirements. 

III-C.4 Section IV—State Reporting and Recordkeeping Checklists (40 CFR

142.14 and 142.15)

This section addresses state reporting and recordkeeping requirements. The state should use these checklists

to explain how state reporting and recordkeeping requirements are consistent with federal requirements. If

state requirements are inconsistent with federal requirements, the state must explain how its requirements

are “no less stringent” as per §142.10. The checklist for the IESWTR is presented in Table III-3.
June 2001 III-12 IESWTR Implementation Guidance

Table III-3: Reporting and Recordkeeping Checklist for the IESWTR

Requirement

Are state policies consistent

with federal requirements? 

If not, please explain.

Each state that has primary enforcement responsibility must keep records of

turbidity measurements for not less than 1 year; information retained must

be set forth in a form which makes possible comparison with turbidity limits

specified in §§141.71, 141.73, 141.173, 141.175.

Each state that has primary enforcement responsibility must keep records of

disinfectant residual measurements and other parameters necessary to

document disinfection effectiveness in accordance with §§141.72 and

141.74, and the reporting requirements of §§141.75 and 141.175; records

must be kept for not less than 1 year.

Each state that has primary enforcement responsibility must keep written

records of decisions made on a system-by-system and case-by-case basis

under the provisions of 40 CFR 141, subpart H or subpart P. 

Each state that has primary enforcement responsibility must keep records of

systems consulting with the state concerning a modification to a

disinfection practice under §141.172(c) including the status of the

consultation.

Each state that has primary enforcement responsibility must keep records of

decisions that a system using alternative filtration technologies as allowed

under §141.173(b) can consistently achieve 99% removal of

Cryptosporidium oocysts; decisions must include state-set enforceable

turbidity limits for each system; copy of the decision must be kept until the

decision is reversed or revised; state must provide a copy of the decision to

the system.

Each state that has primary enforcement responsibility must keep records of

systems required to do filter self-assessment, CPE, or CCP under the

requirements of §141.175.

Each state that has primary enforcement responsibility will keep a list of

Subpart H systems that have had a sanitary survey completed during the

previous year and an evaluation of the state’s program for conducting

sanitary surveys under §141.16(b)(3).

III-C.5 Section V—Special Primacy Requirements (40 CFR 142.16)

See section D. This section provides guidance on how states may choose to meet each special primacy

requirement.

III-C.6 Section VI—Attorney General’s Statement of Enforceability (40 CFR

142.11)

The complete and final primacy revision application must include an Attorney General statement certifying

that the state regulations were duly adopted and are enforceable. The Attorney General statement should
IESWTR Implementation Guidance III-13 June 2001

also certify that the state does not have any audit privilege or immunity laws, or if it has such laws, that

these laws do not prevent the state from meeting the requirements of the Safe Drinking Water Act. If a state

has submitted this certification with a previous revision package, then the state should indicate the date of

submittal and the Attorney General need only certify that the status of the audit laws has not changed since

the prior submittal. An example of an Attorney General statement is presented in Figure III-3.

Figure III-3: Example of Attorney General Statement

Model Language

I hereby certify, pursuant to my authority as (1) and in accordance with the Safe Drinking Water Act as

amended, and (2), that in my opinion the laws of the [state / commonwealth of (3)] [or tribal ordinances of (4)]

to carry out the program set forth in the “Program Description” submitted by the (5) have been duly adopted and

are enforceable. The specific authorities provided are contained in statutes or regulations that are lawfully

adopted at the time this Statement is approved and signed, and will be fully effective by the time the program is

approved.

Guidance For States on Audit Privilege and/or Immunity Laws

In order for EPA to properly evaluate the state’s request for approval, the state Attorney General or independent

legal counsel should certify that the state’s environmental audit immunity and/or privilege and immunity law

does not affect its ability to meet enforcement and information gathering requirements under the Safe Drinking

Water Act. This certification should be reasonably consistent with the wording of the state audit laws and

should demonstrate how state program approval criteria are satisfied.

EPA will apply the criteria outlined in its “Statement of Principles” memo issued on 2/14/97 (See Appendix C)

in determining whether states with audit laws have retained adequate enforcement authority for any authorized

federal programs. The principles articulated in the guidance are based on the requirements of federal law,

specifically the enforcement and compliance and state program approval provisions of environmental statutes

and their corresponding regulations. The Principles provide that if provisions of state law are ambiguous, it will

be important to obtain opinions from the state Attorney General or independent legal counsel interpreting the

law as meeting specific federal requirements. If the law cannot be so interpreted, changes to state laws may be

necessary to obtain federal program approval. Before submitting a package for approval, states with audit

privilege and/or immunity laws should initiate communications with appropriate EPA Regional Offices to

identify and discuss the issues raised by the state’s audit privilege and/or immunity law.
June 2001 III-14 IESWTR Implementation Guidance

Model Language

I. For States with No Audit Privilege and/or Immunity Laws 

Furthermore, I certify that [state / commonwealth of (3)] has not enacted any environmental audit privilege

and/or immunity laws.

II. For States with Audit Laws that do Not Apply to the State Agency Administering the Safe Drinking

Water Act 

Furthermore, I certify that the environmental [audit privilege and/or immunity law] of the [state /

commonwealth of (3)] does not affect (3) ability to meet enforcement and information gathering requirements

under the Safe Drinking Water Act because the [audit privilege and/or immunity law] does not apply to the

program set forth in the “Program Description.” The Safe Drinking Water Act program set forth in the

“Program Description” is administered by (5); the [audit privilege and/or immunity law] does not affect

programs implemented by (5), thus the program set forth in the “Program Description” is unaffected by the

provisions of [state / commonwealth of (3)] [audit privilege and/or immunity law].

III. For States with Audit Privilege and/or Immunity Laws that Worked with EPA to Satisfy

Requirements for Federally Authorized, Delegated or Approved Environmental Programs

Furthermore, I certify that the environmental [audit privilege and/or immunity law] of the [state /

commonwealth of (3)] does not affect (3) ability to meet enforcement and information gathering requirements

under the Safe Drinking Water Act because [state / commonwealth of (3)] has enacted statutory revisions and/or

issued a clarifying Attorney General’s statement to satisfy requirements for federally authorized, delegated or

approved environmental programs.

Seal of Office

_______________________________________

Signature

_______________________________________

Name and Title

_______________________________________

Date

(1) State Attorney General or attorney for the primacy agency if it has independent legal counsel

(2) 40 CFR 142.11(a)(6)(i) for initial primacy applications or 142.12(c)(1)(iii) for primacy program revision

applications..

(3) Name of state or commonwealth

(4) Name of tribe

(5) Name of primacy agency
IESWTR Implementation Guidance III-15 June 2001

III-D. Guidance for IESWTR Special Primacy Requirements

This section contains guidance states can use when addressing the special primacy requirements of 40 CFR

142.16. It specifically addresses the special primacy conditions added for implementation of the Interim

Enhanced Surface Water Treatment Rule (IESWTR). The guidance addresses special primacy conditions in

the same order that they occur in the rule.

States should note that, in several sections, the guidance makes suggestions and offers alternatives that go

beyond the minimum requirements indicated by reading the subsections of §142.16. EPA does this to

provide states with information and/or suggestions that may be helpful to states’ implementation efforts.

Such suggestions are prefaced by “may” or “should” and are to be considered advisory. They are not

required elements of states’ applications for program revision.

§142.16 Special primacy requirements. (b)(1)Enforceable requirements. (ii): States must have the

appropriate rules or other authority to assure PWSs respond in writing to significant deficiencies

outlined in sanitary survey reports required under paragraph (b)(3) of this section no later than 45 days

after receipt of report, indicating how and on what schedule the system will address significant

deficiencies noted in the survey.

Guidance

This special primacy requirement can be satisfied by a description of statutes, rules, and other authorities the

state can use to assure PWSs take the necessary actions as outlined above. The appropriate section(s) of

each source of authority must be cited and copies of the written documents must be included in the program

revision application package. 

In their applications, states may also wish to address their authority to take administrative and/or legal

actions and assess penalties. Additionally, states may include a description of the plan for using their

appropriate rules and/or other authority to achieve the desired actions on the part of PWSs. The plan may

include the following:

C A cover letter that would be included with the sanitary survey report that lists each

significant deficiency and provides notice to the system of the regulatory requirements. The

cover letter would state the date by which the system’s response would be required and

explain that the response would have to indicate how and on what schedule the system

plans to address each significant deficiency.

C Establishment of a “tickler” file to ensure state follow up.

C Follow-up actions for non-responding systems or systems that provide inadequate

responses.
June 2001 III-16 IESWTR Implementation Guidance

§142.16 Special primacy requirements. (b)(1) Enforceable requirements. (iii): States must have the

appropriate rules or other authority to assure that PWSs take necessary steps to address significant

deficiencies identified in sanitary survey reports required under paragraph (b)(3) of this section, if such

deficiencies are within the control of the PWS and its governing body.

Guidance

This special primacy requirement can be satisfied by a description of statutes, rules, and other authority the

state can use to assure PWSs take action necessary to address significant deficiencies. The appropriate

section(s) of each source of authority must be cited and copies of the written documents must be included in

the revision application package. EPA does not believe that the state’s existing authority to address imminent

and substantial endangerment is sufficient to meet this special primacy requirement. 

In addition, states may wish to address their authority to take administrative and/or legal actions and assess

penalties. Additionally, states may wish to include a description of how the appropriate rules and/or other

authority, including formal enforcement actions, will be used to ensure that the PWSs take the steps

necessary to correct significant deficiencies within their control.

EPA believes that many states have existing authorities that are adequate to comply with the intent of this

special primacy requirement. These authorities can often be found in broad statutory language designed to

provide public health protection. 
IESWTR Implementation Guidance III-17 June 2001

§142.16 Special primacy requirements. (b)(3) Sanitary survey: In addition to the general requirements

for sanitary surveys contained in §142.10.(b)(2), an application must describe how the state will

implement a sanitary survey program that meets the requirements in paragraphs (b)(3)(i) through (v) of

this section. For the purposes of this paragraph, “sanitary survey” means an onsite review of the water

source (identifying sources of contamination using results of source water assessments where available),

facilities, equipment, operation, maintenance, and monitoring compliance of a public water system to

evaluate the adequacy of the system, its sources and operations and the distribution of safe drinking

water. 

Guidance 

The special primacy requirements of §142.16(b)(3) describe several additional provisions states must apply

to their sanitary survey programs for systems using surface water or ground water under the direct influence

of surface water as a source. These provisions address the aspects of PWSs that must be evaluated during

the sanitary survey, minimum frequencies for conducting the sanitary surveys, review of disinfection

profiles, and identification of “significant deficiencies” that require immediate corrective action. It also offers

states the flexibility to allow some post-1995 sanitary surveys to serve as the first set required under the

IESWTR; to reduce the frequency of sanitary surveys necessary for community surface water systems

deemed by the state to have outstanding performance; and to conduct sanitary surveys in a phased or staged

manner.

The following guidance addresses each subsection of §142.16(b)(3) (i) through (v) in order. The

arrangement and structure of the state’s description, however, is discretionary, provided the state gives

sufficient detail to demonstrate that its strategy and capacity are adequate for meeting the special primacy

conditions.

References for more detailed guidance

1. Guidance Manual for Sanitary Surveys, USEPA, April 1999 (EPA 815-R-99-016)

Available from: 

www.epa.gov/safewater/mdbp/pdf/sansurv/sansurv.pdf; and 

Safe Drinking Water Hotline: 1-800-426-4791
June 2001 III-18 IESWTR Implementation Guidance

§142.16 Special primacy requirements. (b)(3) Sanitary survey (i): The state must conduct sanitary

surveys for all surface water systems(including groundwater under the influence) that address the eight

sanitary survey components listed in paragraphs (b)(3)(i)(A) through (H) of this section no less frequently

than every three years for community systems and no less frequently than every five years for

noncommunity systems. The state may allow sanitary surveys conducted after December 1995 to serve as

the first set of required sanitary surveys if the surveys address the eight sanitary survey components listed

in paragraphs (b)(3)(i)(A) through (H) of this section.

(A) Source.

(B) Treatment.

(C) Distribution system.

(D) Finished water storage.

(E) Pumps, pump facilities, and controls.

(F) Monitoring and reporting and data verification.

(G) System management and operation.

(H) Operator compliance with state requirements.

Guidance

This special primacy requirement addresses both the scope of the state’s sanitary surveys (eight components

must be included) and the minimum frequency for conducting surveys. States should have adequate

resources to comply with these requirements. States must address scope and frequency of sanitary surveys

in their primacy revision application and are encouraged to address capacity and implementation as well.

Scope and frequency of sanitary surveys

The state must provide adequate information to demonstrate that the sanitary surveys to be performed

address, at a minimum, the eight components listed above. In cases where the state is currently performing

sanitary surveys that meet these minimum requirements, example sanitary survey forms and completed

reports can be used to demonstrate that all eight elements are addressed. If the state does not believe that it

currently performs sanitary surveys that meet the minimum requirements, the revision application must

include details of a plan for upgrading its procedures, as necessary, including examples of sanitary survey

forms that will be used and a description of training for staff in performance of sanitary surveys.

The state must show that sanitary surveys will be conducted no less frequently than every three years for

community systems and no less frequently than every five years for noncommunity systems. EPA believes

that in order to ensure that these surveys will be conducted as an effective preventive tool to identify and

correct water system deficiencies that could pose a threat to public health, states should conduct surveys

three (or five) years from the year the survey was last conducted. Thus, if a sanitary survey for a system on

a three-year cycle is conducted on June 11, 2003, the next survey should be completed by December 2006. 

Capacity

The state’s revision application should address capacity for conducting appropriate sanitary surveys at, or in

excess of, the frequency outlined in §142.16(b)(3)(i). When such capacity exists and the above requirements

are being met or exceeded by an existing program, a summary of the state’s sanitary survey program,

including a brief description of past and future schedules, should be sufficient to demonstrate adequate

capacity.

A state that does not have an existing sanitary survey program that meets these requirements should

describe its proposed program and estimate the resources directed toward sanitary surveys. The state should

explain how the new requirements will affect its program and whether existing resources will be adequate.

When existing resources are clearly inadequate, the state should provide EPA with a plan for obtaining

additional support before the compliance dates of the rule.
IESWTR Implementation Guidance III-19 June 2001

Implementation

Finally, the state should provide EPA with a brief description of its plan for meeting the requirements of

§142.16(b)(3)(i) given existing or planned resources, the number of affected surface water systems,

anticipated follow-up technical assistance and enforcement needs, and other program demands.

References for more detailed guidance

2. Guidance Manual for Sanitary Surveys, USEPA, April 1999 (EPA 815-R-99-016)

Available from: 

www.epa.gov/safewater/mdbp/pdf/sansurv/sansurv.pdf; and 

Safe Drinking Water Hotline: 1-800-426-4791
June 2001 III-20 IESWTR Implementation Guidance

§142.16 Special primacy requirements. (b)(3) Sanitary survey (ii): For community systems determined

by the state to have outstanding performance based on prior sanitary surveys, subsequent sanitary surveys

may be conducted not less than every five years. In its primacy application, the state must describe how it

will decide whether a system has outstanding performance and is thus eligible for sanitary surveys at a

reduced frequency.

Guidance

This special primacy requirement allows the state to decrease the frequency of sanitary surveys for some

community surface water systems from once every 3 years to once every 5 years. The provision is designed

to allow states to direct their limited resources toward those systems that have the greatest potential for

posing public health risks, i.e., those not achieving outstanding performance. States must have a procedure

for determining whether a system should be considered to have outstanding performance that must be

integrated into the sanitary survey process. The procedure should provide inspectors with enough guidance

to ensure consistent implementation.

Criteria states may wish to consider in determining outstanding performance can be found in Section 4.5 of 

Guidance Manual for Conducting Sanitary Surveys for Public Water Systems: Surface Water and Ground

Water Under Direct Influence (GWUDI).

References for more detailed guidance

1. Guidance Manual for Sanitary Surveys: Surface Water and Ground Water Under Direct Influence

(GWUDI), USEPA, April 1999 (EPA 815-R-99-016)

Available from: 

www.epa.gov/safewater/mdbp/pdf/sansurv/sansurv.pdf; and 

Safe Drinking Water Hotline: 1-800-426-4791
IESWTR Implementation Guidance III-21 June 2001

§142.16 Special primacy requirements. (b)(3) Sanitary survey (iii): Components of a sanitary survey

may be completed as part of a staged or phased state review process within the established frequency.

Guidance

Section 142.16(b)(3) requires states to conduct sanitary surveys for surface water systems including

groundwater under the direct influence that address eight components. In view of the fact that states often

have inspections and evaluations conducted on one or more of these PWS components in program efforts

separate from the sanitary surveys, the rule allows for those evaluations and inspections to be used in a

staged or phased review process as long as all eight components are addressed within the required

frequency. For example, the annual onsite inspection required for unfiltered systems, as one criterion to

remain unfiltered, can be used to supplement a full sanitary survey. Other programs whose activities may

serve to address one or more of the components include the following:

C Source Water Assessment and Protection Program

C Wellhead Protection Area Program

C Watershed Control Program

C The Composite Correction Program

C Comprehensive Performance Evaluations

C Operator Training and Certification Programs

C Technical Assistance Programs

C Capacity Development Programs

If a state wishes to conduct sanitary surveys in a staged or phased process, the primacy revision application

should contain a description of relevant programs and activities, how they will be coordinated, and who the

responsible parties will be for follow-up technical assistance and enforcement in response to deficiencies. 

References for more detailed guidance

1. Guidance Manual for Sanitary Surveys: Surface Water and Ground Water Under Direct Influence

(GWUDI), USEPA, April 1999 (EPA 815-R-99-016)

Available from: 

www.epa.gov/safewater/mdbp/pdf/sansurv/sansurv.pdf; and 

Safe Drinking Water Hotline: 1-800-426-4791
June 2001 III-22 IESWTR Implementation Guidance

§142.16 Special primacy requirements. (b)(3) Sanitary survey (iv): When conducting sanitary surveys

for systems required to comply with the disinfection profiling requirements in §141.172 of this chapter,

the state must also review the disinfection profile as part of the sanitary survey.

Guidance

EPA suggests that states address this provision under the treatment component of the general description of

their existing or planned sanitary survey programs. The description should include information on how the

systems that are required to prepare disinfection profiles will be identified and tracked so inspectors will

know when this review is needed. Inspectors should know what format the state will expect the data to be

presented in and how the state will consult with PWSs to evaluate modifications to disinfection practices so

these issues can be discussed during the sanitary survey (see §142.16(g)(2)).

References for more detailed guidance

1. Disinfection Profiling and Benchmarking Guidance Manual, USEPA, August 1999 (EPA 815-R-99-013).

Available from:

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791

3. Guidance Manual for Compliance With the Filtration and Disinfection Requirements for Public Water

Systems Using Surface Water Sources, USEPA, March 1991 (PB93-222933).

Available from:

NTIS

5282 Port Royal Road

Springfield, VA 22161

Phone: 1-800-533-6847

or 

AWWA

6666 West Quincy Avenue

Denver, CO 80235

Phone: 1-800-926-7337

4. Guidance Manual for Sanitary Surveys: Surface Water and Ground Water Under Direct Influence

(GWUDI), USEPA, April 1999 (EPA 815-R-99-016)

Available from: 

www.epa.gov/safewater/mdbp/pdf/sansurv/sansurv.pdf; and 

Safe Drinking Water Hotline: 1-800-426-4791
IESWTR Implementation Guidance III-23 June 2001

§142.16 Special primacy requirements. (b)(3) Sanitary survey (v): In its primacy application, the state

must describe how it will decide whether a deficiency identified during a sanitary survey is significant

for the purposes of paragraph (b)(1)(ii) of this section.

Guidance

During sanitary surveys inspectors often discover a wide range of deficiencies. Some are minor and have

little near-term potential to pose risks to public health or safety. At the other end of the spectrum are those

that are currently supplying drinking water that is unsafe or operating in a manner that threatens the safety

of operators or the public. States must establish procedures for inspectors to use to determine the point

where deficiencies become “significant.” 

The first step in this process should be to define a “significant deficiency.” Many public health professionals

believe that any aspect of a PWS (source, transmission, pumping, treatment, storage, distribution, operation,

maintenance, management, etc.) that may cause, or have potential to cause, risks to public health or safety

should be considered a significant deficiency. EPA does not specify the definition states must use; rather, it

suggests that states use their best professional judgement and expertise to develop their own definitions. One

potential definition that might be used is the following:

Significant deficiency: Any defect in a system’s design, operation, maintenance, or

administration, as well as any failure or malfunction of any system component, that the state

determines to cause, or have the potential to cause, an unacceptable risk to health or that could

affect the reliable delivery of safe drinking water.

The second step may be for the state to develop a procedure whereby inspectors can evaluate system

defects and make a determination regarding “significance”( i.e., does it meet the state definition?). The

procedure might begin with questions to be asked about each defect. A few examples (not intended to be

complete) of questions that may help inspectors in making determinations include the following:

C Does the deficiency cause the potential for contaminants to be introduced to the drinking

water?

C If left uncorrected will the deficiency cause the potential for the introduction of

contaminants at some point in the future?

C Does the deficiency affect treatment in an unacceptable manner?

C Does the deficiency pose risks to the safety of the public or operators?

Finally, it should be helpful for states to develop a list of the most commonly found deficiencies that are

significant and that require immediate corrective actions. EPA would expect the list to be expanded and

modified over time based upon state experience. The following are some examples, organized by each of the

eight sanitary survey components, of system defects that states may consider to be significant and require

immediate corrective action (also not intended to be complete).

Source

C Raw water quality monitoring that is indicative of an immediate sanitary risk.

C Activities or pollution sources in the immediate source water area that will cause sanitary

risks.

C Location of a well making it vulnerable to surface water runoff.
June 2001 III-24 IESWTR Implementation Guidance

C A well that is not properly sealed (details of what is expected should be offered regarding,

sanitary seals, vents, grouting, etc.).

C Spring boxes that are poorly constructed and/or subject to flooding.

Treatment

C The disinfection contact time is inadequate.

C One or more of the unit processes is incapable of producing water that meets standards

under all conditions of raw water quality.

C There are no provisions to warn operators of membrane failures.

C No disinfection profile is available for review (for systems required to develop a disinfection

profile).

Distribution and transmission

C Customers are receiving, and using for drinking water, raw water from the raw water

transmission main.

C The raw water transmission main is equipped with a bypass around the treatment plant and

the bypass does not have an air gap to prevent unintended bypass of untreated water.

C Disinfection residuals in the distribution system regularly do not meet state requirements.

C Pressures in parts of the distribution system fall below 20 psi during peak flows.

C High leakage rates pose unacceptable risks of back siphonage.

Finished water storage

C The elevation of the storage facilities is such that pressures within the distribution system

fall below 20 psi during peak demands.

C The tank is not adequately sealed to prevent entry of contamination (unscreened or poorly

designed vents, overflows, hatches, etc.).

C The elevated tank has not been inspected for sanitary defects for x years.

Pumps, pump facilities, and controls

C The pumping station is used for storage of materials that offer unacceptable potential for

contamination of the water.

C The pumping station is used for storage of materials that pose safety risks to operators.

C Cross connections are present.

C Auxiliary power is needed to keep pressures above 20 psi during commonly experienced

power outages.
IESWTR Implementation Guidance III-25 June 2001

Monitoring, reporting and data verification

C The system has been found to be in significant non-compliance (SNC) for one or more

contaminants or for disinfectant residuals, or is approaching SNC status.

C Operators are using improper procedures and/or methods when conducting onsite lab

analyses.

C The system is not using a certified laboratory.

C The system has been falsifying data

System management and operation

C The system has inadequate personnel to keep the plant manned as required by state

regulations.

C The system has not developed a plan for provision of water during emergencies.

Operator compliance with state requirements

C The system has no certified operator.

C The system’s certified operator is not complying with the state’s continuing education

requirements.

States should note that the above lists of significant deficiencies are provided in this guidance as examples of

deficiencies that states may determine to be significant. The final determination of what constitutes a

significant deficiency will be determined by each state on a case by case basis.

References for more detailed guidance

1. Guidance Manual for Conducting Sanitary Surveys for Public Water Systems: Surface Water and

Ground Water Under Direct Influence (GWUDI), USEPA, April 1999 (EPA 815-R-99-016).

Available from:

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791

2. How to Conduct a Sanitary Survey of Small Water Systems, University of Florida Training, Research

and Education for Environmental Occupations Center (developed under EPA Training Grant T902854),

1998.

Available from:

National Environmental Training Association

5320 North 16th St, Suite 114

Phoenix, AZ 85016

Phone: 602-956-6099
June 2001 III-26 IESWTR Implementation Guidance

3. State Sanitary Survey Resource Directory, AKA EPA/State Joint Guidance on Sanitary Surveys,

Association of State Drinking Water Administrators, 1995.

Available from: 

www.asdwa.org ; or 

ASDWA

1025 Connecticut Ave NW, Suite 903

Washington, DC 20036

4. Guidance Manual for Compliance With the Filtration and Disinfection Requirements for Public Water

Systems Using Surface Water Sources, USEPA, March 1991 (PB93-222933).

Available from:

NTIS

5282 Port Royal Road

Springfield, VA 22161

Phone: 1-800-533-6847

or 

AWWA

6666 West Quincy Avenue

Denver, CO 80235

Phone: 1-800-926-7337
IESWTR Implementation Guidance III-27 June 2001

§142.16 Special primacy requirements. (g)(1) Enforceable requirements: States must have the

appropriate rules or other authority to require PWSs to conduct a Composite Correction Program (CCP)

and to assure that PWSs implement any follow up recommendations that result as part of the CCP (See the

rule for a description of the CCP components).

Background

Many states have raised a concern regarding the interpretation of this special primacy condition and asked

EPA to clarify the intent. Some states have interpreted this special primacy condition to mean the state

must have the authority to require systems to implement recommendations. EPA hereby clarifies that the

intent of this special primacy condition is to ask the state to describe a procedure to assure follow-up on the

outcome of the CCP. 

As discussed in the handbook Optimizing Water Treatment Plant Performance Using the Composite

Correction Program, the CCP has been developed and demonstrated as a method of optimizing surface

water treatment plant performance with respect to protection from microbial pathogens. The approach is

based on establishing effective use of the available water treatment process barriers against passage of

particles to the finished water. The CCP is composed of two components: 1.) Comprehensive Performance

Evaluation (CPE) and 2.) Comprehensive Technical Assistance. A CPE is a through review and analysis of

a plant's performance-based capabilities and associated administrative, operation, and maintenance practices

as they relate to achieving optimum performance from the facility. A CPE does not identify

recommendations or solutions. A CPE identifies performance limiting factors. A CTA is the performance

improvement phase that is implemented if the CPE results indicate performance improvement potential. 

Guidance

The first part of the special primacy requirement can be satisfied by a description of statutes, rules, and

other authority (other than their imminent and substantial endangerment authority) the state can use to

require PWSs to conduct a Composite Correction Program (CCP). The appropriate section(s) of each

source of authority should be cited and copies of the written documents must be included in the revision

application package. The state should explain how the authorities will be used to require CCPs. States may

also wish to address their authority to take administrative and/or legal actions and assess penalties. The

second part of this special primacy requirement can be satisfied with a description of a procedure that will

be used to assure follow up on the outcome of a CCP.

Additionally, states should note that this requirement of the IESWTR is intended to ensure that states have

authority to require comprehensive performance evaluations or comprehensive technical assistance in

situations beyond those in which the IESWTR establishes the requirement for CPEs. Therefore, states may

wish to consider other circumstances under which the requirement for performing a CPE or CTA might be

desirable. States should consider development of prioritization procedures for targeting systems that need

CPEs and should determine what performance-limiting factors (A, B, or C factors) should be corrected. To

obtain the authority to ensure that systems conduct a CTA when necessary, states may want to add a

requirement in their regulations that would require systems to go through with a CTA when the CPE

required by the triggers in §141.175 of the rule show that a CTA would be beneficial. 

Another consideration for states is that §141.175 of the IESWTR requires systems, under certain

circumstances, to have a CPE conducted by the state or a third party approved by the state. If a state does

not have adequate resources to conduct the expected CPEs, it may wish to begin development of a

procedure for approving third parties that have the necessary expertise and meet other criteria established by

the state.
June 2001 III-28 IESWTR Implementation Guidance

References for more detailed guidance

1. Optimizing Water Treatment Plant Performance Using the Composite Correction Program, USEPA,

Revised August 1998 (EPA/625/6-91/027).

Available from: 

Safe Drinking Water Hotline: 1-800-426-4791

2. Optimizing Water Treatment Plant Performance Using the Composite Correction Program, USEPA,

February 1991 (EPA/625/6-91/027).

Available from: 

Safe Drinking Water Hotline: 1-800-426-4791

3. Summary Report: Optimizing Water Treatment Plant Performance With the Composite Correction

Program, USEPA, 1990 (EPA/625/8-90/017).

Available from: 

Safe Drinking Water Hotline: 1-800-426-4791
IESWTR Implementation Guidance III-29 June 2001

§142.16 Special primacy requirements. (g)(2) State practices or procedures. (i): Section 141.172(a)(3)

of this chapter—How the state will approve a more representative annual data set other than the data set

determined under §141.172(a)(1) or (2) of this chapter for the purpose of determining applicability of the

requirements of §141.172 of this chapter.

*NOTE: Systems which requested the use of a more representative annual data set must have had this

request approved by the state such that applicable systems would begin disinfection profiling by April 1,

2000. This one-time provision occurs prior to the date which states are required to submit their primacy

application. Therefore, a state’s primacy application which does not address the above provision

(§142.16(g)(2)(i)) will still be considered complete. However, if a state chooses to address the above special

primacy condition, the guidance below will aid the state in doing so.

Guidance

Section 141.172(a)(3) allows systems to request the state to approve their use of a more representative data

set for determining if the system is required to develop a disinfection profile. Requests for approval to use a

more representative data set may occur when a system has modified its treatment in a manner such that the

data collected pursuant to §141.172(a)(1) or (2) no longer reflect the potential for production of disinfection

byproducts. Use of a more representative data set would also be appropriate if the sampling, handling,

and/or analysis of the data collected pursuant to §141.172(a)(1) or (2) were of questionable quality.

Alternative data may also be necessary due to atypical climatological events or changes in source water. 

EPA believes that requests for use of alternative data sets are best handled by states on a case-by-case

basis. Therefore, to meet this special primacy requirement, states’ applications for program revision must

demonstrate that each request for use of a more representative data set will be evaluated on its merits and

approved only when a data set exists, or can be collected within the established time frame, that is more

representative of the system’s potential for production of disinfection byproducts.

References for more detailed guidance

1. Disinfection Profiling and Benchmarking Guidance Manual, USEPA, August 1999 (EPA 815-R-99-013).

Available from: 

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791

2. Microbial and Disinfection Byproduct Rules Simultaneous Compliance Guidance Manual, USEPA,

August 1999 (EPA 815-R-99-015).

Available from: 

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791
June 2001 III-30 IESWTR Implementation Guidance

§ 142.16 Special primacy requirements. (g)(2) State practices or procedures. (ii): Section 141.172(b)(5)

of this chapter—How the state will approve a method to calculate the logs of inactivation for viruses for a

system that uses either chloramines or ozone for primary disinfection.

Guidance

Section 141.172(b)(5) of the IESWTR requires systems that use ozone or chloramines as primary

disinfectants to calculate the logs of inactivation of viruses using a method approved by the state. This

calculation is in addition to the calculation of the logs inactivation for Giardia lamblia and is required

because, for these disinfectants, EPA expects greater CT will be necessary to achieve the necessary virus

inactivation than will be necessary for inactivation of Giardia lamblia. In their primacy revision

applications, states must describe how they will approve a method to calculate the logs of inactivation for

viruses.

When determining virus inactivation, PWSs will be required to calculate the total CT from the point(s) of

disinfectant application to the first customer. This procedure for determining CT for purposes of disinfection

profiling under the IESWTR is outlined in §141.172(b) of the rule. It differs from that of the Surface Water

Treatment Rule (SWTR) guidance which simply required a demonstration that minimum inactivation

requirements were being met but did not require a demonstration of the extent to which the requirements

were exceeded.

After the PWS has determined its daily peak hour’s CT, it must determine the logs of inactivation for

viruses. EPA suggests that states, to the extent practicable, use the Guidance Manual for Compliance With

the Filtration and Disinfection Requirements for Public Water Systems Using Surface Water Sources

(SWTR Guidance Manual) for determining how systems should calculate the logs of inactivation of viruses,

and thus meet this special primacy requirement. Suggested methods of doing so are as follows:

For systems using chloramines as a primary disinfectant

Table E-13 of the SWTR Guidance Manual presents CT values for 2 log, 3 log, and 4 log inactivation of

viruses by chloramine at temperatures ranging from <1E C to 25E C. The table is appropriate for use by

systems that add chlorine prior to ammonia and, therefore, get some benefit of a short-lived free chlorine

residual. The basis for the inactivation values in Table E-13, is discussed in Appendix F (Section F.2.3

Chloramines) of the manual. Systems that add the two chemicals concurrently, or those adding ammonia

first, have little free chlorine and cannot use Table E-13 but may determine viral inactivation efficiencies by

using the protocol found in Appendix G of the manual.

For systems using ozone as a primary disinfectant

Table E-11 of the SWTR Guidance Manual shows CT values for 2 log, 3 log, and 4 log inactivation of

viruses by ozone over a temperature range of <1E C to 25E C. EPA believes it to be appropriate for states

to have PWSs use Table E-11 for calculating the logs of inactivation of viruses. Appendix F (F.2.4 Ozone)

of the SWTR Guidance Manual offers a short discussion of the basis for the values in the table.

Other methods

States may approve other methods for calculation of the logs of inactivation for viruses for systems using

ozone or chloramines as long as the methods are adequately explained in the primacy revision application

and are technically correct.
IESWTR Implementation Guidance III-31 June 2001

References for more detailed guidance

1. Guidance Manual for Compliance With the Filtration and Disinfection Requirements for Public Water

Systems Using Surface Water Sources, USEPA, March 1991 (PB93-222933).

Available from:

NTIS

5282 Port Royal Road

Springfield, VA 22161

Phone: 1-800-533-6847

or 

AWWA

6666 West Quincy Avenue

Denver, CO 80235

Phone: 1-800-926-7337

2. Alternative Disinfectants and Oxidants Guidance Manual, USEPA, April 1999 (EPA 815-R-99-014).

Available from:

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791
2

 More detailed guidance and strategies for simultaneous achievement of acute and chronic public health

protection are addressed in the two listed EPA references.

June 2001 III-32 IESWTR Implementation Guidance

§142.16 Special primacy requirements. (g)(2) State practices or procedures. (iii): Section 141.172(c) of

this chapter—How the state will consult with PWSs to evaluate modifications to disinfection practice.

Guidance

The IESWTR requires systems to develop a disinfection profile if they have concentrations of TTHM or

HAA5 at or above 80 percent of the respective maximum contaminant levels. Systems that are required to

develop disinfection profiles, and that later want to make a significant change to their disinfection practice,

must consult with the state prior to making such change. As described in §141.172(c)(1) of the IESWTR,

significant changes include:

C Changes to the point of disinfection

C Changes to the disinfectant(s) used in the treatment plant

C Changes to the disinfection process

C Any other modification identified by the state

Examples of state-identified modifications may include source water, pretreatment, contact basin geometry

and baffling, or in some instances changes in pH. 

This requirement of the IESWTR is intended to ensure that systems attempting to reduce disinfection

byproduct production do not make changes that cause unintended and unacceptable increases in microbial

risks. In order for §141.172(c)(1) of the IESWTR to be effective, states must identify all systems that are

required to develop a disinfection profile and provide them with guidance in terms of when, and under what

circumstances, consultation is necessary. It should be noted that the IESWTR requires “consultation” with

the state but does not prescribe the outcome of the consultation. 

In their applications for program revision, states must explain how they will consult with systems to evaluate

changes in disinfection practices. EPA suggests that states, in the consultation process, consider the

following:2

C Why the change is being proposed.

C The positive impacts of the change.

C The negative impacts of the change.

C The alternative benchmark.

C Are there alternatives that achieve the desired goal and, if so, have they been evaluated?

Finally, the state should work with the PWS in an effort to reach a conclusion that considers, weighs, and

balances the risks of microbial contaminants and disinfection byproducts. Ultimately, the state and system

should jointly make a public-health-based decision using all available information.

References for more detailed guidance

1. Disinfection Profiling and Benchmarking Guidance Manual, USEPA, August 1999 (EPA 815-R-99-013).

Available from: 

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791

2. Microbial and Disinfection Byproduct Rules Simultaneous Compliance Guidance Manual, USEPA,

August 1999 (EPA 815-R-99-015).

Available from: 

www.epa.gov/safewater/mdbp/implement.html; and

Safe Drinking Water Hotline: 1-800-426-4791
IESWTR Implementation Guidance III-33 June 2001

§142.16 Special primacy requirements. (g)(2) State practices or procedures.(iv): Section 141.173(b) of

this chapter—For filtration technologies other than conventional filtration treatment, direct filtration,

slow sand filtration, or diatomaceous earth filtration, how the state will determine that a public water

system may use a filtration technology if the PWS demonstrates to the state, using pilot plant studies or

other means, that the alternative filtration technology, in combination with disinfection treatment that

meets the requirements of §141.172(b) of this chapter, consistently achieves 99.9 percent removal and/or

inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivation of viruses, and 99

percent removal of Cryptosporidium oocysts. For a system that makes this demonstration, how the state

will set turbidity performance requirements that the system must meet 95% of the time and that the system

may not exceed at any time at a level that consistently achieves 99.9 percent removal and/or inactivation

of Giardia lamblia cysts, 99.99 percent removal and/or inactivation of viruses, and 99 percent removal of

Cryptosporidium oocysts.

Guidance

The SWTR and IESWTR establish performance standards for several long-established types of surface

water treatment technologies, including conventional treatment, direct filtration, slow sand filtration, and

diatomaceous earth filtration. These technologies, when properly designed and operated, used in conjunction

with disinfection and contact time, and applied to appropriate surface waters, are capable of protecting

against the health risks associated with Giardia lamblia, Legionella, viruses, Cryptosporidium, and other

pathogens. Section 141.173(b) of the IESWTR allows PWSs to use technologies other than those

mentioned above if they demonstrate to the state’s satisfaction that the chosen technology consistently

meets the rule’s minimum removal and inactivation requirements, and the state approves the use of the

technology. When the state grants approval for the use of alternative technologies, it must establish a

turbidity performance limit the system must meet at least 95 percent of the time and a turbidity limit the

system may not exceed at any time. The state must set the turbidity limits at levels that ensure the removal

and/or inactivation requirements are consistently achieved.

To qualify for the authority to use the discretion provided for by §141.173(b) of the IESWTR, states must,

in their primacy revision application, describe how they will determine whether a PWS will or will not be

granted approval for use of an alternative technology and how the state will establish the requisite turbidity

performance standards.

Most states have a review and approval process that addresses all significant modifications to PWSs (not

just alternative technologies). In their review of treatment technologies, states generally consider all relevant

components necessary to provide consistently safe drinking water including raw water quality and its

variability, pretreatment needs, design flow rates, disinfection, storage, monitoring, and operation and

maintenance requirements. Because alternative technologies generally do not have long performance

histories to base approval/permitting decisions upon, states may wish to apply an additional margin of

scrutiny in their review process. The technologies should be evaluated not only on the basis of finished

water quality, but also with consideration of operational complexities, the potential for cross connections,

redundancy, the ability to handle variable raw water qualities, leaching of contaminants, and long term

reliability. Pilot studies are often necessary to adequately demonstrate that an alternative technology is

appropriate for use at a particular site.

Guidance has been developed for states to use in determining how to grant approvals for alternative

technologies. This guidance generally does not address the current concern for Cryptosporidium. The

protocols that have been developed and used to assess the performance of technologies in terms of Giardia

lamblia removal may, however, be revised for Cryptosporidium removal evaluations. EPA recommends

that states consider the guidance on these issues presented in Section 4.3.7 and Appendix M of the SWTR

Guidance Manual (reference 3) as well as the Western States Workgroup’s Consensus Protocol for

Evaluation and Acceptance of Alternate Surface Water Filtration Technologies in Small System

Applications, 1992 (reference 1). The protocol developed by the Western States Workgroup establishes a
June 2001 III-34 IESWTR Implementation Guidance

procedure and criteria for evaluation of alternative filtration technologies and should be particularly useful.

The following is an outline of the protocol’s procedural steps.

1) System component evaluation for leaching of contaminants.

2) Demonstration of Giardia (and Cryptosporidium) removal performance.

a. Microscopic Particulate Analyses (MPA).

b. Giardia/Cryptosporidium surrogate particle removal evaluations.

c. Particle size analysis demonstration for Giardia (and Cryptosporidium) removal credit.

d. Live Giardia/Cryptosporidium challenge studies.

3) On-site demonstration of performance effectiveness.

a. Prior testing of an identical system on a similar water.

b. Conditional acceptance with a performance bond.

c. Pilot testing with MPAs, appropriate monitoring, and final engineering report.

The final step in the process is for states to establish turbidity limits for the technologies. This was not

necessary under the SWTR’s requirements because the limits for alternative technologies defaulted to the

performance limits established for slow sand filtration. When establishing the performance limits, states

should give consideration to, among other things, cyst removal efficiencies, potential for interference with

disinfection, potential for interference with bacteriological testing, and the technology (failure indicators)

redundant components.

References for more detailed guidance

1. Consensus Protocol for Evaluation and Acceptance of Alternate Surface Water Filtration Technologies in

Small System Applications, Western States Workgroup, April 1992.

Available from:

Safe Drinking Water Hotline: 1-800-426-4791

2. State Alternative Technology Approval Protocol, Association of State Drinking Water

Administrators/USEPA, 1996.

Available from:

www.asdwa.org; or

ASDWA

1025 Connecticut Avenue, NW Suite 903

Washington, DC 20036

3. Guidance Manual for Compliance With the Filtration and Disinfection Requirements for Public Water

Systems Using Surface Water Sources, USEPA, March 1991 (PB93-222933).

Available from:

NTIS

5282 Port Royal Road

Springfield, VA 22161

Phone: 1-800-533-6847

or 

AWWA

6666 West Quincy Avenue

Denver, CO 80235

Phone: 1-800-926-7337
Section IV.

Other Resources and

Guidance
June 2001 IV-2 IESWTR Implementation Guidance

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IESWTR Implementation Guidance IV-3 June 2001

IV-A. Technical Information Available on the IESWTR

A series of guidance manuals support the IESWTR. The manuals will aid EPA, state agencies, and affected

PWSs in implementing this rule and will help ensure that implementation among these groups is consistent.

Summaries of the manuals and information on how to obtain them are provided below. The six technical

guidance manuals associated with the IESWTR are:

T Disinfection Profiling and Benchmarking Guidance Manual

T Guidance Manual for Compliance with the Interim Enhanced Surface Water Treatment

Rule: Turbidity Provisions

T Alternative Disinfectants and Oxidants Guidance Manual

T Guidance Manual for Conducting Sanitary Surveys of Public Water Systems

T Uncovered Finished Water Reservoirs Manual

T Microbial and Disinfection Byproducts Rules Simultaneous Compliance Guidance Manual

Disinfection Profiling and Benchmarking Guidance Manual (EPA 815-R-99-013)

Objective: Help determine if a disinfection profile (an evaluation of current disinfection practices) is

required and how to do one; when a disinfection benchmark must be determined and how

to extract it from the profile, and; how a PWS must use the benchmark, in consultation

with the state, to assure protection from microbial risk is maintained when the system

changes its disinfection practice.

Contents: The manual provides detailed information on the following subjects: applicability of the

profiling and benchmarking requirements to public water systems; procedures for

generating a disinfection profile, including example profiles; methods for calculating the

disinfection benchmark, including example calculations; the use of the benchmark in

modifying disinfection practices, communication with the state, and assessing significant

changes to disinfection practices; the development of the profiling and benchmarking

regulations; the significance of the log inactivation concept and CT values for inactivations

achieved by various disinfectants; and the determination of contact time.

Guidance Manual for Compliance with the Interim Enhanced Surface Water Treatment Rule:

Turbidity Provisions (EPA 815-R-99-010)

Objective: The first section provides information regarding specific requirements of the IESWTR

relating to turbidity and is intended for experienced operators and others in the regulated

community. The second section of the document provides background on concepts

surrounding turbidity and serves as a primer for less experienced operators and individuals.

Contents: The first section contains key regulatory requirements, including combined filter effluent

monitoring and individual filter monitoring; recordkeeping and reporting requirements;

additional compliance issues, such as compliance schedules, public notification,

variances/exemptions, and follow-up action requirements; approved methods and additional

methods and additional measurement and calibration issues; components and description of

a filter self-assessment, and; components and description of a Comprehensive Performance

Evaluation. The second section of the manual includes more basic information on turbidity;

description of the particles (both natural and man-made) that typically contribute to

turbidity; discussion of typical steps in a treatment process and how turbidity is removed or

created in each step; discussion of turbidity in different source waters with an emphasis of

how changes in source water affect turbidity, and; basic turbidimeter design.
June 2001 IV-4 IESWTR Implementation Guidance

Alternative Disinfectants and Oxidants Guidance Manual (EPA 815-R-99-014)

Objective: To provide technical data and engineering information on disinfectants and oxidants that are

not as commonly used as chlorine so that systems can evaluate their options for developing

disinfection schemes to control water quality problems such as zebra mussels and Asiatic

clams, and oxidation to control water quality problems associated with iron and manganese. 

Contents: The manual discusses six disinfectants and oxidants: ozone, chlorine dioxide, potassium

permanganate, chloramines, ozone/hydrogen peroxide combinations, and ultraviolet light. A

decision tree is provided to assist in evaluating which disinfectant, or disinfectants, is most

appropriate given certain site-specific conditions (e.g., water quality conditions, existing

treatment, and operator skill). The manual also contains a summary of existing alternative

disinfectants used in the U.S. and cost estimates for the use of alternative disinfectants.

Guidance Manual for Conducting Sanitary Surveys of Public Water Systems (EPA 815-R-99-016)

Objective: Provides an overview of how to conduct a sanitary survey of all water systems using

surface water and ground water under the direct influence of surface water. It is intended to

help state agencies improve their sanitary survey programs where needed.

Contents: The manual provides information about the objective and regulatory context of sanitary

surveys. It covers four principal stages of a sanitary survey: planning, including preparatory

steps to be taken by inspectors before conducting the on-site portion conducting the on-site

survey, compiling a sanitary survey report, and performing follow-up activities. 

Uncovered Finished Water Reservoirs Manual (EPA 815-R-99-011)

Objective: To provide information on ways to limit water quality degradation in existing uncovered

finished water reservoirs. 

Contents: Provides detailed information on the following subjects: developing and implementing

comprehensive open finished water reservoir management plans based on site-specific

conditions; identifying potential sources of contamination in open finished water reservoirs

and potential mitigation measures; employing different methods to control the degradation

of water quality while it resides in the reservoir; monitoring schemes that can be used to

characterize water quality and identify water quality degradation before it becomes severe

and difficult to correct.

Microbial and Disinfection Byproducts Rules Simultaneous Compliance Guidance Manual (EPA

815-R-99-015)

Objective: To assist PWSs on complying simultaneously with various drinking water regulations (e.g.,

Stage 1 DBPR, IESWTR, Lead and Copper Rule, and the Total Coliform Rule). The

manual discusses operational problems systems may encounter when implementing these

rule.

Contents: The manual provides detailed information on the requirements in the Stage 1 DBPR and

the IESWTR.
IESWTR Implementation Guidance IV-5 June 2001

IV-B. Profiling Spreadsheet

An electronic spreadsheet to assist PWSs performing disinfection profiles is available on the EPA

web site (see http://www.epa.gov/safewater/mdbp/implement.html).

IV-C. List of Labs Approved to Perform Analysis for the ICR

For an updated list, please refer to the Safe Drinking Water Hotline (1.800.426.4791) or the EPA

web site (www.epa.gov/ogwdw/lablist/lname.html).

IV-D. Rule Presentation

A presentation that can be used for workshops for the IESWTR is available in Power Point format

on the Drinking Water Academy web site.

(http://www.epa.gov/safewater/dwa/electronic/M-DBPmodule.html).

IV-E. Fact Sheets

The following pages are fact sheets on the rules. They may be useful in conveying information to water

systems, new personnel, and for educating stakeholders about the rules. The fact sheets are included in this

section are:

T Drinking Water Priority Rulemaking: Microbial and Disinfection Byproduct Rules

T Interim Enhanced Surface Water Treatment Rule

T Disinfection Profiling and Benchmarking

T Interim Enhanced Surface Water Treatment Rule: Quick Reference Guide

Links to these manuals can be found at the website:

www.epa.gov/safewater/mdbp/implement.html. 

They are also available free of charge (while supplies last) from:

L The National Service for Environmental Publications (NSCEP,

formerly NCEPI) at 1.800.490.9198 

L The Office of Water Resource Center at 1.202.260.7786.

Customers can purchase these documents for a fee from:

L The National Technical Information Service (NTIS) at

1.800.553.6847. 

For more information, contact EPA’s Safe Drinking Water Hotline at

1.800.426.4791.
June 2001 IV-6 IESWTR Implementation Guidance

This page is left intentionally blank.
United States Office of Water EPA 816-F-01-012

Environmental Protection (4607) June 2001

Agency

Drinking Water Priority Rulemaking:

Microbial and Disinfection Byproduct Rules

Disinfection of drinking water is one of the major public health advances in the 20th century. One hundred

years ago, typhoid and cholera epidemics were common throughout American cities and disinfection was a

major factor in reducing these epidemics. However, the disinfectants themselves can react with naturallyoccurring materials in the water to form unintended byproducts which may pose health risks. 

Over the past ten years, we have also learned that there are specific microbial pathogens, such as

Cryptosporidium, that are highly resistant to traditional disinfection practices. In 1993, Cryptosporidium

caused 400,000 people in Milwaukee to experience intestinal illness. More than 4,000 were hospitalized, and

at least 50 deaths have been attributed to the disease. There have also been cryptosporidiosis outbreaks in

Nevada, Oregon, and Georgia over the past several years.

A major challenge for water suppliers is how to balance the risks from microbial pathogens and disinfection

byproducts. It is important to provide protection from these microbial pathogens while simultaneously

ensuring decreasing health risks to the population from disinfection byproducts (DBPs). The Safe Drinking

Water Act (SDWA) Amendments, signed by President Clinton in August 1996, required EPA to develop

rules to achieve these goals.

These new rules are a product of six years of collaboration between the water industry, environmental and

public health groups, and local, state and federal government. This fact sheet contains general information

about the two new rules and others that are a part of the Microbial-Disinfectants and Disinfection

Byproducts (M-DBP) Rules. Separate fact sheets focus on the Interim Enhanced Surface Water Treatment

Rule (EPA 816-F-01-013) and the Stage 1 Disinfectants and Disinfection Byproducts Rule (EPA 816-F-01-

014).

Schedule of M-DBP Rules

December 16, 1998 – Final Rule Interim Enhanced Surface Water Treatment Rule and 

Stage 1 Disinfectants and Disinfection Byproducts Rule

June 8, 2001 – Final Rule Filter Backwash Recycling Rule

Summer 2001 – Final Rule Long Term 1 Enhanced Surface Water Treatment Rule

Spring/Summer 2002 – Final Rule Ground Water Rule

May 2002 – Final Rule Long Term 2 Enhanced Surface Water Treatment Rule and 

Stage 2 Disinfectants and Disinfection Byproducts Rule
PUBLIC HEALTH CONCERNS

Most Americans drink tap water that meets all existing health standards all the time. These new rules will

further strengthen existing drinking water standards and thus increase protection for many water systems.

In 1990, EPA’s Science Advisory Board concluded that exposure to microbial contaminants such as

bacteria, viruses, and protozoa (e.g., Giardia lamblia and Cryptosporidium) was likely the greatest

remaining health risk management challenge for drinking water suppliers. Acute health effects from exposure

to microbial pathogens is documented and associated illness can range from mild to moderate cases lasting

only a few days to more severe infections that can last several weeks and may result in death for those with

weakened immune systems.

While disinfectants are effective in controlling many microorganisms, they react with natural organic and

inorganic matter in source water and the distribution system to form potentially harmful DBPs. Many of

these DBPs have been shown to cause cancer and reproductive and developmental effects in laboratory

animals. More than 200 million people consume water that has been disinfected. Because of the large

population exposed, health risks associated with DBPs, even if small, need to be taken seriously. 

EXISTING REGULATIONS

C Surface Water Treatment Rule – The Surface Water Treatment Rule, promulgated in 1989,

applies to all public water systems using surface water sources or ground water sources

under the direct influence of surface water. It establishes maximum contaminant level goals

(MCLGs) for viruses, bacteria and Giardia lamblia. It also includes treatment technique

requirements for filtered and unfiltered systems that are specifically designed to protect

against the adverse health effects of exposure to these microbial pathogens. 

• Total Coliform Rule – The Total Coliform Rule, revised in 1989, applies to all PWSs and

establishes a maximum contaminant level (MCL) for total coliforms.

C Total Trihalomethane Rule – In 1979, EPA set an interim MCL for total trihalomethanes of

0.10 mg/l as an annual average. This applies to any community water system serving at

least 10,000 people that adds a disinfectant to the drinking water during any part of the

treatment process.

• Information Collection Rule – The Information Collection Rule, promulgated in 1996,

established monitoring and data reporting requirements for large public water systems

serving at least 100,000 people to support the M-DBP rulemaking process. This rule was

intended to provide EPA with information on the occurrence in drinking water of microbial

pathogens and DBPs. In addition, EPA collected engineering data on how PWSs currently

control such contaminants.
INTERIM ENHANCED SURFACE WATER TREATMENT

RULE AND STAGE 1 DISINFECTANTS AND DISINFECTION

BYPRODUCTS RULE

EPA published the Interim Enhanced Surface Water Treatment Rule and Stage 1 Disinfectants and

Disinfection Byproducts Rule in December 1998. The final rules resulted from formal regulatory

negotiations with a wide range of stakeholders that took place in 1992-93 and 1997.

Interim Enhanced Surface Water Treatment Rule

The Interim Enhanced Surface Water Treatment Rule applies to systems using surface water, or ground

water under the direct influence of surface water, that serve 10,000 or more persons. The rule also includes

provisions for states to conduct sanitary surveys for surface water systems regardless of system size. The

rule builds upon the treatment technique requirements of the Surface Water Treatment Rule with the

following key additions and modifications: 

• Maximum contaminant level goal (MCLG) of zero for Cryptosporidium.

• 2-log Cryptosporidium removal requirements for systems that filter.

• Strengthened combined filter effluent turbidity performance standards.

• Individual filter turbidity monitoring provisions.

• Disinfection profiling and benchmarking provisions.

• Systems using ground water under the direct influence of surface water now subject to the new rules

dealing with Cryptosporidium.

• Inclusion of Cryptosporidium in the watershed control requirements for unfiltered public water systems.

• Requirements for covers on new finished water storage facilities.

• Sanitary surveys, conducted by states, for all surface water systems regardless of size.

The Interim Enhanced Surface Water Treatment Rule, with tightened turbidity performance criteria and

required individual filter monitoring, is designed to optimize treatment reliability and to enhance physical

removal efficiencies to minimize the Cryptosporidium levels in finished water. In addition, the rule includes

disinfection benchmark provisions to assure continued levels of microbial protection while facilities take the

necessary steps to comply with new DBP standards.

Stage 1 Disinfectants and Disinfection Byproducts Rule

The final Stage 1 Disinfectants and Disinfection Byproducts Rule applies to community water systems and

non-transient non-community systems and transient noncommunity systems using chlorine dioxide,

(including systems serving fewer than 10,000 people), that add a disinfectant to the drinking water during

any part of the treatment process.
The Stage 1 Disinfectants and Disinfection Byproducts Rule includes the following key provisions: 

• Maximum residual disinfectant level goals (MRDLGs) for chlorine (4 mg/L), chloramines (4 mg/L), and

chlorine dioxide (0.8 mg/L). 

• Maximum contaminant level goals (MCLGs) for three trihalomethanes (bromodichloromethane (zero),

dibromochloromethane (0.06 mg/L), and bromoform (zero)), two haloacetic acids (dichloroacetic acid

(zero) and trichloroacetic acid (0.3 mg/L)), bromate (zero), and chlorite (0.8 mg/L).

• MRDLs for three disinfectants (chlorine (4.0 mg/L), chloramines (4.0 mg/L), and chlorine dioxide (0.8

mg/L)). 

• MCLs for total trihalomethanes (0.080 mg/L) - a sum of the three listed above plus chloroform,

haloacetic acids (HAA5) (0.060 mg/L)- a sum of the two listed above plus monochloroacetic acid and

mono- and dibromoacetic acids), and two inorganic disinfection byproducts (chlorite (1.0 mg/L)) and

bromate (0.010 mg/L)).

• A treatment technique for removal of DBP precursor material. 

The terms MRDLG and MRDL, which are not included in the SDWA, were created during the negotiations

to distinguish disinfectants (because of their beneficial use) from contaminants. The rule also includes

monitoring, reporting, and public notification requirements for these compounds and describes the best

available technology (BAT) upon which the MRDLs and MCLs are based. 

FUTURE RULES

Long Term 1 Enhanced Surface Water Treatment Rule

While the Stage 1 Disinfectants and Disinfection Byproducts Rule will apply to systems of all sizes, the

Interim Enhanced Surface Water Treatment Rule only applies to systems serving 10,000 or more people.

The Long Term 1 Enhanced Surface Water Treatment Rule, expected in 2001, will strengthen microbial

controls for small systems (i.e. those systems serving fewer than 10,000 people). The rule will also prevent

significant increase in microbial risk where small systems take steps to implement the Stage 1 Disinfectants

and Disinfection Byproducts Rule.

EPA believes that the rule will generally track the approaches in the Interim Enhanced Surface Water

Treatment Rule for improved turbidity control, including individual filter monitoring and reporting. The rule

will also address disinfection profiling and benchmarking.

Long Term 2 Enhanced Surface Water Treatment Rule and Stage 2 Disinfectants and Disinfection

Byproduct Rule

The SDWA, as amended in 1996, requires EPA to finalize a Stage 2 Disinfectants and Disinfection

Byproducts Rule by May 2002. Although the 1996 Amendments do not require EPA to finalize a Long

Term 2 Enhanced Surface Water Treatment Rule along with the Stage 2 Disinfectants and Disinfection

Byproducts Rule, EPA believes it is important to finalize these rules together to ensure a proper balance

between microbial and DBP risks.

EPA began discussions with stakeholders in December 1998 on the direction for these rules. EPA

anticipates proposed rules in 2001. The intent of the rules is to provide additional public health protection, if

needed, from DBPs and microbial pathogens.
Ground Water Rule

EPA is finalizing the Ground Water Rule which specifies the appropriate use of disinfection and, just as

importantly, addresses other components of ground water systems to ensure public health protection. There

are more than 158,000 public ground water systems. Almost 89 million people are served by community

ground water systems, and 20 million people are served by non-community ground water systems.

Ninety-nine percent (157,000) of ground water systems serve fewer than 10,000 people. However, systems

serving more than 10,000 people serve 55 percent (more than 60 million) of all people who get their

drinking water from public ground water systems.

Filter Backwash Recycling Rule

The Filter Backwash Recycling Rule establishes a standard to return all recycle flows to a point that

incorporates all treatment processes of the system’s existing conventional or direct filtration systems or at an

alternate location approved by the state. The regulation will apply to public water systems that use surface

water or ground water under the direct influence of surface water, practice conventional or direct filtration,

and recycle spent filter backwash, sludge thickener supernatant, or liquids from dewatering processes. The

rule was promulgated on June 8, 2001.

ADDITIONAL INFORMATION

EPA encourages public input into regulation development. Public meetings and opportunities for public

comment on M-DBP rules are announced in the Federal Register. EPA’s Office of Ground Water and

Drinking Water also provides this information for the M-DBP rules and other programs in its online

Calendar of Events.

For more information, contact EPA’s Safe Drinking Water Hotline, 1-800- 426-4791, or see the Office of

Ground Water and Drinking Water web page at http://www.epa.gov/safewater/standards.html. 
This page is left intentionally blank.
United States Office of Water EPA 816-F-01-013

Environmental Protection (4607) June 2001

Agency

Interim Enhanced Surface Water 

Treatment Rule

Disinfection of drinking water is one of the major public health advances in the 20th century. One hundred

years ago, typhoid and cholera epidemics were common through American cities and disinfection was a

major factor in reducing these epidemics. However, the disinfectants themselves can react with naturallyoccurring materials in the water to form unintended byproducts which may pose health risks. 

In the past ten years, however, we have learned that there are specific microbial pathogens, such as

Cryptosporidium, that are resistant to traditional disinfection practices. In 1993, Cryptosporidium caused

400,000 people in Milwaukee to experience intestinal illness. More than 4,000 were hospitalized, and at least

50 deaths have been attributed to the disease. There have also been cryptosporidiosis outbreaks in Nevada,

Oregon, and Georgia over the past several years.

Amendments to SDWA in 1996 require EPA to develop rules to balance the risks. It is important to

strengthen protection against microbial contaminants, especially Cryptosporidium, and at the same time,

reduce potential health risks from disinfection byproducts. The new Interim Enhanced Surface Water

Treatment Rule and Stage 1 Disinfectants and Disinfection Byproducts Rule are among the first of a set of

rules under the Amendments. This fact sheet focuses on the Interim Enhanced Surface Water Treatment

Rule. A separate fact sheet focuses on the Stage 1 Disinfectants and Disinfection Byproducts Rule (EPA

816-F-01-014). 

PUBLIC HEALTH CONCERNS FROM

MICROBIAL CONTAMINANTS IN DRINKING

WATER 

In 1990, EPA’s Science Advisory Board concluded that exposure to microbial contaminants such as

bacteria, viruses, and protozoa (e.g., Giardia lamblia and Cryptosporidium) was likely the greatest

remaining health risk management challenge for drinking water suppliers. Acute health effects from exposure

to microbial pathogens is documented and associated illness can range from mild to moderate cases lasting

only a few days to more severe infections that can last several weeks and may result in death for those with

weakened immune systems.

WHO MUST COMPLY WITH THE

RULE?

The Interim Enhanced Surface Water Treatment Rule applies to public water systems that use surface water

or ground water under the direct influence of surface water (GWUDI) and serve at least 10,000 people. In

addition, states are required to conduct sanitary surveys for all surface water and GWUDI systems,

including those that serve fewer than 10,000 people.
WHAT DOES THE RULE REQUIRE?

The Interim Enhanced Surface Water Treatment Rule amends the existing Surface Water Treatment Rule to

strengthen microbial protection, including provisions specifically to address Cryptosporidium, and to address

risk trade-offs with disinfection byproducts. The final rule includes treatment requirements for the

waterborne pathogen Cryptosporidium. In addition, systems must continue to meet existing requirements

for Giardia lamblia and viruses. Specifically, the rule includes:

• Maximum contaminant level goal (MCLG) of zero for Cryptosporidium.

• 2-log Cryptosporidium removal requirements for systems that filter.

• Strengthened combined filter effluent turbidity performance standards for systems using conventional

and direct filtration.

• Individual filter turbidity monitoring provisions for systems using conventional and direct filtration.

• Disinfection profiling and benchmarking provisions.

• Systems using ground water under the direct influence of surface water now subject to the new rules

dealing with Cryptosporidium.

• Inclusion of Cryptosporidium in the watershed control requirements for unfiltered public water systems.

• Requirements for covers on new finished water storage facilities.

• Sanitary surveys, conducted by states, for all surface water systems regardless of size.

The rule, with tightened turbidity performance criteria and individual filter monitoring requirements, is

designed to optimize treatment reliability and to enhance physical removal efficiencies to minimize the

Cryptosporidium levels in finished water. Turbidity requirements for combined filter effluent will remain at

least every four hours, but continuous monitoring (record results every 15 minutes) will be required for

individual filters at conventional and direct filtration plants. In addition, the rule includes disinfection

profiling and benchmarking provisions to assure continued levels of microbial protection while facilities take

the necessary steps to comply with new DBP standards.

WHAT ARE THE COMPLIANCE DEADLINES?

States have until December 16, 2000 to adopt and implement the requirements of this regulation. States may

request up to a two year extension to adopt the rule. Simultaneous compliance with the Stage 1

Disinfectants and Disinfection Byproduct Rule, promulgated at the same time as IESWTR, will be achieved

as follows:

Public water systems that use surface water or ground water under the direct influence of surface water,

either in whole or in part, and serve a population of 10,000 or more generally must comply with

requirements of this rule by January 1, 2002. Systems with elevated levels of disinfection by-products were

required to develop a disinfection profile beginning no later than March 31, 2000. In cases where capital

improvements are needed to comply with the rule, states may grant systems up to an additional two years to

comply.
WHAT ARE THE COSTS AND BENEFITS OF

THE RULE?

EPA estimates that implementation of the Interim Enhanced Surface Water Treatment Rule will:

• Improvements in filtration at water systems will increase public health protection by reducing the level

of exposure to Cryptosporidium and other pathogens (i.e., Giardia, or other waterborne bacterial or

viral pathogens) in drinking water supplies ;

• Decrease the likelihood of endemic (constant low-level presence of a disease or infection) illness from

Cryptosporidium by 110,000 to 463,000 cases annually and related health costs, as well as incidences

of illness from Giardia and other waterborne pathogens; and,

• Reduce the likelihood of the occurrence of outbreaks of cryptosporidiosis (illness from

Cryptosporidium) and their associated economic costs by providing a larger margin of safety against

such outbreaks for some systems.

The total annualized national cost for implementing the Interim Enhanced Surface Water Treatment Rule is

$307 million. EPA believes that the benefits exceed the costs. The rule will result in increased costs to public

water systems for improved turbidity treatment, monitoring, disinfection benchmarking and covering new

finished water storage facilities, as well as state implementation costs. 

EPA estimates that 92 percent of households will incur an increase in their water bill of less than $1 per

month; 7 percent of households will incur an increase in their water bills of between $1 - $5 per month; and

less than 1 percent will incur an increase of between $5-8 per month.

WHAT TECHNICAL INFORMATION WILL BE

AVAILABLE ON THE RULE?

A series of guidance manuals have been developed to support the Interim Enhanced Surface Water

Treatment Rule. The manuals will aid EPA, state agencies and affected public water systems in

implementing the IESWTR. The guidance manual are available on EPA’s website at

www.epa.gov/safewater/mdbp/implement.html.

Disinfection Benchmarking Guidance Manual

Objective: To help determine if a disinfection profile (an evaluation of current disinfection practice) is

required and how to do one; when a disinfection benchmark must be determined and how to extract it from

the profile; and how a public water system must use the benchmark, in consultation with the state, to assure

protection from microbial risk is maintained when the system changes disinfection practice.

Contents: The manual provides detailed information on the following subjects: applicability of the profiling

and benchmarking requirements to public water systems; procedures for generating a disinfection profile,

including example profiles; methods for calculating the disinfection benchmark, including example

calculations; the use of the benchmark in modifying disinfection practices, communicating with the state,

and assessing significant changes to disinfection practices; the development of the profiling and

benchmarking regulations; the significance of the log inactivation concept and CT values for inactivations

achieved by various disinfectants; and the determination of contact time.
Guidance Manual for Compliance with the Interim Enhanced Surface Water Treatment Rule:

Turbidity Provisions

Objective: The first section provides technical information regarding specific requirements of the Interim

Enhanced Surface Water Treatment Rule relating to turbidity and is intended for experienced operators and

others in the regulated community. The second section of the document provides background on concepts

surrounding turbidity and serves as a primer for less experienced operators and individuals.

Contents: The first section contains key regulatory requirements including combined filter effluent

monitoring and individual filter monitoring; recordkeeping and reporting requirements; additional compliance

issues such as compliance schedule, public notification, variances/exemptions, and follow-up action

requirements; approved methods and additional measurement and calibration issues; components and

description of an filter self-assessment; and components and description of a Comprehensive Performance

Evaluation. The second section of the manual includes more basic information on turbidity; description of

the particles (both natural and man-made) which typically contribute to turbidity; discussion of typical steps

in a treatment process and how turbidity is removed or created in each step; discussion of turbidity in

different source waters with an emphasis of how changes in source water effect turbidity; and basic

turbidimeter design.

Alternative Disinfectants and Oxidants Guidance Manual

Objective: To provide technical data and engineering information on disinfectants and oxidants that are not

as commonly used as chlorine, so that systems can evaluate their options for developing disinfection

schemes to control water quality problems such as zebra mussels and Asiatic clams, and oxidation to control

water quality problems associated with iron and manganese.

Contents: The manual discusses six disinfectants and oxidants: ozone, chlorine dioxide, potassium

permanganate, chloramines, ozone/hydrogen peroxide combinations, and ultraviolet light. A decision tree is

provided to assist in evaluating which disinfectant(s) is most appropriate given certain site-specific conditions

(e.g., water quality conditions, existing treatment and operator skill). The manual also contains a summary

of existing alternative disinfectants use in the United States and cost estimates for the use of alternative

disinfectants. 

Microbial and Disinfection Byproducts Simultaneous Compliance Manual

Objective: To assist public water systems on complying simultaneously with various drinking water

regulations (e.g., Stage 1 Disinfectants and Disinfection Byproducts Rule, Interim Enhanced Surface Water

Treatment Rule, Lead and Copper Rule and the Total Coliform Rule). The manual discusses operational

problems systems may encounter when implementing these rules.

Contents: The manual provides detailed information on the requirements in the Stage 1 Disinfectants and

Disinfection Byproducts Rule and the Interim Enhanced Surface Water Treatment Rule and issues involved

with simultaneously complying with other rules.

Guidance Manual for Conducting Sanitary Surveys of Public Water Systems

Objective: The guidance manual provides an overview of how to conduct a sanitary survey of all water

systems using surface water and ground water under the direct influence of surface water. It is intended to

help state agencies improve their sanitary survey programs where needed.

Contents: The manual provides information about the objective and regulatory context of sanitary surveys.

It covers four principal stages of a sanitary survey: planning, including preparatory steps to be taken by

inspectors before conducting the onsite portion; conducting the onsite survey; compiling a sanitary survey

report; and performing follow-up activities. 
Uncovered Finished Water Reservoirs

Contents: The manual provides detailed information on the following subjects: developing and

implementing comprehensive open finished water reservoir management plans based on site-specific

conditions; identifying potential sources of contamination in open finished water reservoirs and potential

mitigation measures; employing different methods to control the degradation of water quality while it resides

in the reservoir; monitoring schemes that can be used to characterize water quality and identify water quality

degradation before it becomes severe and is difficult to correct.

For more information, contact EPA’s Safe Drinking Water Hotline, 1.800.426.4791, or see the Office of

Ground Water and Drinking Water web page at http://www.epa.gov/safewater/standards.html. 
This page is left intentionally blank.
The process consists of the following 3 steps:

Ø Determining if a PWS must develop a disinfection profile—§141.172 (a)

Ù Developing the disinfection profile—§141.172 (b)

Ú Calculating the disinfection benchmark and consulting with the state—§141.172 (c) 

United States Office of Ground Water EPA 816-F-98-017b 

Environmental Protection and Drinking Water December 16, 1998

Agency Washington, DC 20460

Fact Sheet: 

Disinfection Profiling and

Benchmarking

The Interim Enhanced Surface Water Treatment

Rule (IESWTR) requires certain public water

systems (PWSs) to evaluate their disinfection

practices and work with the state to assure there

are no unintended reductions in microbial

protection

Is your PWS affected?

Your PWS is affected if it is a surface water or GWUDI* system that—

• Serves 10,000 or more people; and,

• Has Total Trihalomethanes $ 0.064 mg/L or Haloacetic Acids $ 0.048 mg/L. 

* Ground water under the direct influence (of surface water)
Ø Determining if a PWS Must Develop a Disinfection Profile

How can a PWS determine if it must develop a disinfection profile?

A PWS determines if it must establish a disinfection profile using 4 consecutive quarters of TTHM and HAA5 data.

If the PWS has an annual average level of TTHM $ 0.064 mg/L or an annual average level of HAA5 $ 0.048mg/L,

it must then develop a disinfection profile. 

Alternatively, a PWS may choose to develop a disinfection profile and not collect these data.

How should a PWS collect TTHM and HAA5 data?

‘ Most PWSs serving 100,000 or more people have collected TTHM and HAA5 data under the 1996

Information Collection Rule (ICR). These systems must use these data (from calendar year 1998) to

determine if they must profile, unless the state determines there is a more representative data set for them to

use. PWSs must submit these data to the state no

later than December 1999 (Timeline Milestone ã).

‘ A PWS that has not collected data under the ICR but

has 4 consecutive quarters of TTHM compliance

data and HAA5 occurrence data may use these

data to determine if it must profile. The PWS must

submit these data to the state for approval no later

than April 1999 (Timeline Milestone â). 

‘ A PWS that has no data or inadequate data for TTHM and HAA5 should collect 4 consecutive quarters of

data. The PWS should submit these data to the state and determine whether or not to develop a disinfection

profile no later than March 2000 (Timeline Milestone ä).

What are the monitoring requirements for TTHM and HAA5 data?

‘ TTHM and HAA5 data must be collected during the same quarter.

‘ For TTHM, samples must be taken in accordance with current TTHM monitoring requirements under 

40 CFR 141.12 and 141.30. For HAA5, at least 4 samples must be taken per plant per quarter in accordance with 

routine monitoring requirements under 40 CFR 141.12 and 141.30.

‘ At least 25 percent of the samples for TTHM and HAA5 shall be taken at locations within the distribution system

reflecting maximum residence time of the water in the system.

‘ The remaining 75 percent of the samples for TTHM and HAA5 shall be taken at representative locations in the

distribution system, taking into account the number of people served, the different sources of water, and the

different treatment methods employed.

‘ Analytical Methods and Handling Requirements

TTHM: EPA 502.2 HAA5: EPA 552.1

EPA 524.2 EPA 552.2

EPA 551 Std. 6251 B

Which labs may conduct analyses for HAA5?

‘ Any lab that received approval under the 1996 ICR

‘ Any lab using ICR-approved methods
April 1999 December 1999

1 2

March 2001

3

March 2000

Timeframe for collecting 4 consecutive 

quarters of TTHM and HAA5 data

Timeframe for collecting 12 months of disinfection profiling data

Publication

December 16, 1998

Timeline

4

Ù Developing the Disinfection Profile

How does a PWS develop a disinfection profile?

‘ The disinfection profile is developed by compiling daily Giardia lamblia log inactivations computed over a

period of 12 months. In addition, a disinfection profile for daily virus log inactivations must be developed for

PWSs that use either chloramines or ozone for primary disinfection. The log inactivation values are calculated

using daily measurements of operational data collected during peak-hour flows. This disinfection profiling must

be completed no later than March 2001 (Timeline Milestone å).

‘ A PWS that has 3 years of existing operational data may use these data to develop a disinfection profile as

long as the state has determined that these data are substantially equivalent to data that would be collected under

the IESWTR.

‘ The PWS must keep the disinfection profile on file to be reviewed during its Sanitary Survey.

Ú Calculating the Disinfection Benchmark and Consulting with the State

A PWS required to develop a disinfection profile that subsequently decides to make a significant modification to its

disinfection practice must calculate a disinfection benchmark and consult with the state prior to implementing such a

change. The state consultation process helps assure that the PWS will meet the new disinfection byproduct

standards without compromising protection from microbial contaminants.

How does a PWS calculate a disinfection benchmark?

A disinfection benchmark is an indicator of disinfection effectiveness and depends upon the inactivation of Giardia

lamblia (or viruses). The benchmark is determined by calculating the average daily inactivation value for each of 12

consecutive months. The lowest monthly average becomes the disinfection benchmark. If the system has data from

more than 1 year, it repeats this calculation for each year. The benchmark is the average of the lowest month’s

value for each of the years.

What are significant modifications to a disinfection practice?

Significant modifications to disinfection practices include:

‘ Changes to the point of disinfection ‘ Changes to the disinfectant(s) used in the treatment plant

‘ Changes to the disinfection process ‘ Any other modification identified by the state
PLEASE LOOK INSIDE:

Your water system is expected to

be affected by the requirements

of the new IESWTR

United States

Environmental Protection Agency

(4101)

Washington, DC 20460

Official Business

Penalty for Private Use

$300 

Bulk Rate

Postage and Fees Paid

EPA

G-35

More information can be obtained from:

L Your state’s primacy agency

L The EPA Safe Drinking Water Hotline, Telephone: 1.800.426.4791
United States

Environmental Protection

Agency

Office of Water

(4606)

EPA 816-F-01-011

May 2001

www.epa.gov/safewater

Interim Enhanced Surface Water

Treatment Rule:

A Quick Reference Guide

Overview of the Rule

Title

Interim Enhanced Surface Water Treatment Rule (IESWTR)

63 FR 69478 - 69521, December 16, 1998, Vol. 63, No. 241

Revisions to the Interim Enhanced Surface Water Treatment Rule (IESWTR), the Stage 1

Disinfectants and Disinfection Byproducts Rule (Stage 1 DBPR), and Revisions to State

Primacy Requirements to Implement the Safe Drinking Water Act (SDWA) Amendments

66 FR 3770, January 16, 2001, Vol 66, No. 29

Purpose

Improve public health control of microbial contaminants, particularly Cryptosporidium.

Prevent significant increases in microbial risk that might otherwise occur when systems

implement the Stage 1 Disinfectants and Disinfection Byproducts Rule.

General

Description

Builds upon treatment technique approach and requirements of the 1989 Surface Water

Treatment Rule. Relies on existing technologies currently in use at water treatment plants.

Utilities

Covered

Sanitary survey requirements apply to all public water systems using surface water or

ground water under the direct influence of surface water, regardless of size. All remaining

requirements apply to public water systems that use surface water or ground water under

the direct influence of surface water and serve 10,000 or more people.

Major Provisions

Regulated Contaminants

Cryptosporidium 4 Maximum contaminant level goal (MCLG) of zero.

4 99 percent (2-log) physical removal for systems that filter.

4 Include in watershed control program for unfiltered systems.

Turbidity Performance

Standards

Conventional and direct filtration combined filter effluent:

4 £ 0.3 nephelometric turbidity units (NTU) in at least 95 percent of

 measurements taken each month.

4 Maximum level of 1 NTU.

Turbidity Monitoring Requirements

(Conventional and Direct Filtration)

Combined Filter Effluent 4 Performed every 4 hours to ensure compliance with turbidity

 performance standards.

Individual Filter Effluent 4 Performed continuously (every 15 minutes) to assist treatment plant

 operators in understanding and assessing filter performance.

Additional Requirements

4 Disinfection profiling and benchmarking.

4 Construction of new uncovered finished water storage facilities prohibited.

4 Sanitary surveys, conducted by the state, for all surface water and ground water under the

 direct influence of surface water systems regardless of size (every 3 years for community water systems

 and every 5 years for noncommunity water systems).
For additional information

on the IESWTR

Call the Safe Drinking Water

Hotline at 1-800-426-4791;

visit the EPA web site at

www.epa.gov/safewater; or

contact your State drinking

water representative.

Additional material is

available at www.epa.gov/

safewater/mdbp/

implement.html.

Critical Deadlines and Requirements

For Drinking Water Systems

February 16, 1999 Construction of uncovered finished water reservoirs is prohibited.

March 1999 Public water systems lacking ICR or other occurrence data begin 4 quarters of

applicability monitoring for TTHM and HAA5 to determine if disinfection

profiling is necessary.

April 16, 1999 Systems that have 4 consecutive quarters of HAA5 occurrence data that meet

the TTHM monitoring requirements must submit data to the state to determine

if disinfection profiling is necessary.

December 31, 1999 Public water systems with ICR data must submit it to states to determine if

disinfection profiling is necessary.

April 1, 2000 Public water systems must begin developing a disinfection profile if their annual

average (based on 4 quarters of data) for TTHM is greater than or equal to

0.064 mg/L or HAA5 is greater than or equal to 0.048 mg/L.

March 31, 2001 Disinfection profile must be complete.

January 1, 2002 Surface water systems or ground water under the direct influence of surface

water systems serving 10,000 or more people must comply with all IESWTR

provisions (e.g., turbidity standards, individual filter monitoring).

For States

December 16, 2000 States submit IESWTR primacy revision applications to EPA (triggers interim

primacy).

January 2002 States begin first round of sanitary surveys.

December 16, 2002 Primacy extension deadline - all states with an extension must submit primacy

revision applications to EPA.

December 2004 States must complete first round of sanitary surveys for community water

systems.

December 2006 States must complete first round of sanitary surveys for noncommunity water

systems.

Public Health Benefits

Implementation of

the IESWTR will

result in . . .

4 Increased protection against gastrointestinal illnesses from

 Cryptosporidium and other pathogens through improvements in filtration.

4 Reduced likelihood of endemic illness from Cryptosporidium by 110,000 to

 463,000 cases annually.

4 Reduced likelihood of outbreaks of cryptosporidiosis.

Estimated impacts of

the IESWTR

include . . .

4 National total annualized cost: $307 million

4 92 percent of households will incur an increase of less than $1 per month.

4 Less than 1 percent of households will incur an increase of more than $5 per

 month (about $8 per month).

Profiling and Benchmarking

Public water systems must evaluate impacts on microbial risk before changing

disinfection practices to ensure adequate protection is maintained. The three major steps

are:

4 Determine if a public water system needs to profile based on TTHM and HAA5 levels

 (applicability monitoring)

4 Develop a disinfection profile that reflects daily Giardia lamblia inactivation for at least a year

 (systems using ozone or chloramines must also calculate inactivation of viruses)

4 Calculate a disinfection benchmark (lowest monthly inactivation) based on the profile and

 consult with the state prior to making a significant change to disinfection practices
IESWTR Implementation Guidance IV-25 June 2001

IV-F. Frequently Asked Questions

TABLE OF CONTENTS

1.0 Interim Enhanced Surface Water Treatment Rule ..................................... 27

1.1 Cryptosporidium ................................................... 27

1.2 Disinfection Profiling And Benchmarking ................................. 28

1.3 Turbidity Standards (Combined Filter Effluent) ............................. 32

1.4 Individual Filter Provisions ............................................ 32

1.5 Alternative Filtration Technologies ...................................... 34

2.0 General Program Requirements ................................................. 35

2.1 Primacy ......................................................... 35

2.2 Violations, SDWIS Reporting and SNC Definitions .......................... 36

2.3 Qualified Operators ................................................. 37
June 2001 IV-26 IESWTR Implementation Guidance

This page is left intentionally blank.
IESWTR Implementation Guidance IV-27 June 2001

1.0 Interim Enhanced Surface Water Treatment Rule

1.1 Cryptosporidium

For further information, see the following rule sections:

Citation Part Title

§141.32(e)(10) Public Notification

§141.201 Public Notification of Drinking Water Violations

§141.52 Maximum Contaminant Level Goals for Microbiological Contaminants

Q: Why do filtered systems have a Cryptosporidium removal requirement and unfiltered systems do

not?

A: Systems that have met the SWTR filtration avoidance criteria must now incorporate

Cryptosporidium into their watershed protection programs. If a system meeting the SWTR

avoidance criteria fails to address Cryptosporidium under the IESWTR, they will be required to

filter within 18 months to meet the removal requirements. As before, any failure to meet the

SWTR avoidance criteria requires filtration within 18 months. More stringent requirements may

be placed on systems avoiding filtration in future regulations.

Q: Can a system use UV for Cryptosporidium inactivation and receive credit for it under the

IESWTR?

A: A system may use UV; however, it cannot use UV to meet the requirements of the IESWTR. A

system must physically remove 99 percent of oocysts using filtration alone.

Q: Is an oocyst that is not viable considered to be Cryptosporidium or not?

A: Since the rule requires systems to measure turbidity, not the viability of oocysts, it is not relevant

to the enforceable requirements of the rule. Present analytical methods cannot reliably distinguish

between oocysts that are infective or viable and those that are not.

Q: What does EPA have in mind in terms of Cryptosporidium controls on the watershed? 

A: The same types of prevention measures that have been taken to address Giardia may be used to

address Cryptosporidium. Whether or not additional steps are needed will be determined by an

onsite assessment of each watershed, currently conducted by the states on an annual basis. Each

water system should assess potential sources of Cryptosporidium in its watershed and identify

and carry out measures to control the potential adverse impacts on water quality from these

sources. Ultimately monitoring should help to determine if these measures have been successful in

controlling the sources, but monitoring is not currently required by the regulations due to

limitations of the analytical methods.

Q: Does the Cryptosporidium MCLG of zero apply to all species or just Cryptosporidium parvum?

A: The MCLG was set at the genus level because EPA believes that adequate data are not available

to determine that only Cryptosporidium parvum infects humans. 
June 2001 IV-28 IESWTR Implementation Guidance

1.2 Disinfection Profiling And Benchmarking

For further information, see the following rule sections:

Citation Part Title

§141.172(a) Disinfection Profiling and Benchmarking (Determination of systems required to profile)

§141.172(b) Disinfection Profiling and Benchmarking (Disinfection profiling)

§141.172(c) Disinfection Profiling and Benchmarking (Disinfection benchmarking)

Q: Why are systems required to collect TTHM and HAA5 data to determine applicability for

disinfection profiling under the IESWTR?

A: For surface water systems that chlorinate, and most do, some of the conditions (e.g. increased

disinfectant dose and increased contact time) that accelerate creation of TTHMs and HAA5 are

identical to those that increase inactivation ratios for viruses and Giardia lamblia cysts.

Therefore, it is logical that surface water systems that have elevated TTHMs and/or HAA5 will

consider adjusting these variables to reduce the level of disinfection byproducts. Disinfection

profiling and benchmarking is designed to ensure such adjustments are not made without giving

full consideration of the positive and negative impacts.

Q: Can the TTHM and HAA5 data collected for applicability monitoring be used to qualify for

reduced monitoring for the Stage 1 DBPR?

A: The data can be used if the samples were collected at the appropriate location and frequency as

required by §141.132(b)(1)(i) (i.e. routine monitoring) and were analyzed by a certified laboratory

using approved methods under §141.132 or approved ICR methods. Samples collected for

applicability monitoring only do not have to be analyzed by a certified lab, but the lab must use

approved ICR analytical methods.

Q: What exactly is meant by consultation with the state for systems making changes to their

disinfection process?

A: EPA believes that states will consult relatively extensively with systems making significant

changes to disinfection. Most states have extensive procedures in place for approval of water

system modifications. The rule does not require the consultation to be a specific process or

require specific types of documentation, however, states must describe “how they will consult” in

their primacy revision application (§ 142.16(h)) .

Q: Will systems be required to calculate another disinfection benchmark after implementation of

enhanced coagulation under the Stage 1 DBPR begins? 

A: Benchmarking is a one-time provision under the IESWTR. It does not have to be repeated when

processes are changed a second time. EPA believes a similar process will be carried out in most

states for every change in disinfection.

Q: What if you use one watershed with low levels of DBPPs for x months and then switch to

another watershed with higher levels of DBPPs? 

A: The system should discuss the change in source with the state and the state should determine if

the disinfection profile is representative of normal operating conditions. Although not required by

the regulation, the state may choose to have the system perform an additional profile before

allowing modifications. Also, the state and system should review the data together to determine its

value for decision making and use it accordingly.
IESWTR Implementation Guidance IV-29 June 2001

Q: May a system use data from many years ago (e.g., 7 or 8 years ago) to develop a disinfection

profile under the IESWTR?

A: The rule does not specify which years of data can be grandfathered for profiling, however, a state

should carefully review older data to determine if it is still representative of normal operating

conditions. The profile must reflect inactivation through the entire treatment plant.

Q: If a system does not have to submit its profile to the state upon completion, how can the state

determine if the system is in compliance with this provision? 

A: A state will determine system compliance with this provision during the system’s sanitary survey.

Q: Does a water system serving 10,000 or more people, which purchases water from a Subpart H

system that has decided to go directly to profiling, need to perform applicability monitoring? 

A: No, as long as the purchased water is the only Subpart H source serving the system. Both the

seller and the purchaser need to inform the state of this decision by December 31, 1999, and

should clearly indicate that the purchaser is not performing the applicability monitoring because

the seller has decided to go directly to profiling. The state should have documentation that there is

an agreement between the seller and purchaser. 

Q: How should a system develop a disinfection profile under the IESWTR if it experiences

emergency conditions requiring addition of high levels of disinfectants while gathering data?

A: As part of the consultation with the state, the system should note any effect on the benchmark

caused by the emergency. An emergency that is only a few hours or days in duration will likely be

averaged out, since daily results are part of an average. The system and state should put any

unusual situation in proper prospective when consulting over the benchmark and make decisions

accordingly.

Q: If a system does not normally operate for 12 consecutive months, how will it collect 4 quarters

of applicability monitoring data necessary to determine whether the system is required to

profile?

A: Seasonal systems should collect samples for the quarters they operate and base the applicability

determination on all available sample data. The system has the option to forego TTHM/HAA5

applicability monitoring and conduct profiling. The disinfection profile would be developed for the

months the system is operational.

Q: Is there an advantage for systems to begin monitoring early for TTHM and HAA5?

A: Yes. In addition to addressing the early requirements of the IESWTR for Subpart H systems

serving $10,000, systems will know more about their treatment process, and seasonal variations.

EPA would also encourage systems with conventional treatment to initiate TOC monitoring to

assess the need to meet treatment technique requirements of the Stage 1 DBPR.

Q: Is switching from gas to liquid (or vice versa) chlorine considered a “significant change” for

the purposes of setting a benchmark and consulting with the state?

A: No, switching from gas to liquid, or liquid to gas, chlorine would not be considered a significant

change, but states may require notification of such change.

Q: What happens when ICR data has missing values or the state believes the data is not

representative? Must this “bad data” still be used to determine if a disinfection profile must be

developed?

A: The state may determine whether or not to consider the ICR data “bad.” If the state determines

that TTHM and HAA5 data are not representative, the state should inform the system and ask

the system to collect TTHM and HAA5 data to determine if profiling is necessary.
June 2001 IV-30 IESWTR Implementation Guidance

Q: If a system is planning to switch to ozone for protozoan control and will, as a result, decrease

virus inactivation, should the state discourage the system from making this switch?

A: Not necessarily. The state should carefully examine the treatment operations in the system and

the source water. The ultimate determination should be made on a case-by-case basis. The

Disinfection Profiling and Benchmarking Guidance Manual contains more detailed information.

Q: Will there be an electronic template for calculating CT values?

A: An electronic template has been developed and is available with other technical assistance

materials related to these rules on EPA’s Website

(www.epa.gov/safewater/mdbp/implement.html). 

Q: Since we are putting a burden on the system to develop a disinfection profile can we limit the

time of year that monitoring is required to focus on the worst case?

A: No. Affected systems serve 10,000 or more people and generally already collect all or most of the

information necessary for developing a profile. Regardless of whether or not they already have

the data, the rule requires systems to develop a 1-year disinfection profile (unless the system does

not operate year-round; then the profile is developed for the months the seasonal system is

operational). The full year is necessary to examine the maximum possible disinfection, water use,

and water quality scenarios. In addition, the full year of data will provide information to the

systems on seasonal strategies to achieve compliance.

Q: If a system is on reduced monitoring for TTHM, does it have to return to routine monitoring for

the applicability monitoring under the IESWTR?

A: No, for the purpose of applicability monitoring, the system may remain on reduced monitoring for

TTHM samples. EPA believes that the samples, because they are taken at a point in the

distribution system that represents the maximum residence time, are a worst case sample.

Systems are however, required to take 4 quarters of routine samples for HAA5 for the profiling

applicability monitoring, as most non-ICR systems have not monitored for HAA5. 

Q: What if a system has some HAA5 data but not four samples per plant (incomplete data)? Do

they have to collect more samples to see if disinfection profiling is necessary?

A: The system would have to collect a full data set meeting the requirements of the rule or notify the

state by December 31, 1999 that they will go directly to profiling.

Q: If initial TTHM and HAA5 levels suggest that the final annual average will exceed the levels

that trigger disinfection profiling, can a system go directly to profiling, or must they complete

the monitoring?

A: The system can go directly to profiling. It must, however, notify the state in writing of its intent to

do so by December 31, 1999.

Q: Is there any difference in the requirements for calculation of Giardia lamblia and virus

inactivation between the IESWTR’s disinfection profiling requirements and the SWTR’s

requirements? 

A: The Surface Water Treatment Rule requires Subpart H systems to show they meet a minimum

level of inactivation for Giardia lamblia and viruses, but only unfiltered systems are required to

use the CT procedure. However, many systems exceed the minimum requirements by a large

margin. 

The IESWTR, on the other hand, requires systems to show the inactivation achievable through

the entire treatment plant (from point(s) of disinfectant application to the first user). When

systems are considering changes to disinfection practices, this showing of full inactivation

potential is important for ascertaining the full impact of those changes on microbial protection.
IESWTR Implementation Guidance IV-31 June 2001

Q: If a system needs to temporarily increase its chlorine levels in response to an emergency during

the year of the disinfection profile—is the profile still valid?

A: Yes, the profile would still be valid. The profile should cover each day the system is operating

and short-term increases in disinfectant levels should have little effect on the final benchmark.

Systems and states can put unusual circumstances in perspective when they consult over a

disinfection benchmark.

Q: Under the disinfection profiling and benchmarking provisions of the IESWTR, must a system

take TTHM and HAA5 samples at the same time? If the system wishes to use grandfathered

data, do the data have to have been collected at the same time?

A: EPA intends to liberally interpret the “at the same time” provisions of §141.172 such that TTHM

and HAA5 samples would be deemed acceptable for applicability determinations if they are

collected during the same four quarters.

Q: What is the consequence of “failure to develop a profile”?

A: If a system is required to develop a disinfection profile under the provisions of §141.172 and fails

to do so, this failure would constitute a treatment technique violation.

Q: Can a state approve a treatment change while the profiling requirement is in place but before

profiling is complete? What about treatment changes already approved?

A: The requirement to prepare a disinfection profile is triggered by elevated levels of TTHMs or

HAA5 pursuant to §141.172(a)(6), or by notification of the state of its intent to comply with the

disinfection profiling requirement as if the applicability monitoring had been conducted and the

results required the preparation of the disinfection profile. Once the profiling requirement has

been triggered, no significant changes can be made to the system’s disinfection practices without

consultation with the state. However, the state can consult with the system and allow changes

they determine to be appropriate prior to beginning or completing the disinfection profile. The

EPA recognizes that it may not always be practical to postpone necessary changes in disinfection

practices until completion of the profile.

Q: Can a system use 6 months of ICR data and 6 months of monitoring data if the state approves it

as better than the final 12 months of ICR data? 

A: Yes, a system would be able to use this data if approved by the state as a more representative

data set under the provisions of §141.172 (a)(4) or (5)(v).

Q: Under §141.172(b)(2), a system with more than one point of disinfection must conduct

monitoring at each disinfection segment to measure pH, temperature, and CT values. Can a

system use data from a worst case scenario (maximum flow) to satisfy this requirement?

A: The rule requires that monitoring be performed at each disinfection segment. The Disinfection

Profiling and Benchmarking Guidance Manual contains more detailed information. 

Q: Can states use a different method to calculate a disinfection profile? 

A: States must require systems to develop disinfection profiles as provided in §141.172(b)(4) and

(5). States always have the option to adopt rules that are equally or more stringent to those of

EPA. This option offers the possibility that state’s might develop alternative procedures that EPA

could find to be equally stringent and protective of public health.

Q: There is a note in the Guidance Manual for Compliance With the Filtration and Disinfection

Requirements for PWSs Using Surface Water Sources that the CT values for inactivation of

viruses by chloramines expressed in Table E-13 are suitable for use only with systems that add

chlorine prior to ammonia. Is this true and, if so, why?

A: The above referenced guidance manual was specifically designed to aid systems in complying

with the SWTR, not the IESWTR. As explained in the guidance, the CT values in Table E-13
June 2001 IV-32 IESWTR Implementation Guidance

were based directly on experimental data developed using preformed chloramines to determine

inactivation of Hepatitis A Virus (HAV). HAV is less resistant to preformed chloramines than are

some other viruses including rotavirus. Rotavirus is, on the other hand, very sensitive to free

chlorine and, in field practices where chlorine is added prior to ammonia, it was assumed there

would be sufficient contact time with free chlorine to inactivate the rotavirus. When preformed

chloramines are used or when ammonia is added prior to chlorine, the free chlorine will not be

available for inactivation of rotavirus. For these reasons, Table E-13 should not be used to

determine compliance with the inactivation requirements of the SWTR when ammonia is added

prior to chlorine or when preformed chloramines are used. The guidance manual suggests that

inactivation studies be performed in these cases to ensure adequate inactivation of viruses.

The IESWTR, however, requires development of a disinfection profile so a disinfection

benchmark can be calculated. Changes in disinfection practices are then to be measured against

the benchmark to ensure that there is no unintended reduction in microbial protection when

systems change disinfection practices to comply with the Stage 1 DBPR. For the purpose of

developing a disinfection profile, the data in Table E-13 is acceptable as long as all profiles and

subsequent benchmarks are developed in a similar manner so that comparisons of benchmarks

are consistent.

1.3 Turbidity Standards (Combined Filter Effluent)

For further information, see the following rule sections:

Citation Part Title

§141.73(a)(3) Filtration

§141.173(a), (b) Filtration

Q: In terms of compliance with the combined filter effluent turbidity levels, does 0.3 NTU really

mean 0.349 NTU and does 1 NTU really mean 1.49 NTU?

A: Yes, due to rounding of significant figures. 

Q: A system may substitute continuous turbidity monitoring for grab sample monitoring every four

hours. Which results of the continuous monitoring would the system report?

A: The system is required to record results every four hours. Each month, the system must report

the total number of filtered water turbidity measurements recorded, the number and percentage of

the recorded measurements taken which are less than or equal to 0.3 NTU, and the date and

value of recorded measurements greater than 1 NTU.

1.4 Individual Filter Provisions

For further information, see the following rule sections:

Citation Part Title

§141.174(a), (b) Filtration Sampling Requirements

§141.175(a), (b) Reporting and Recordkeeping Requirements

§142.16(g)(1) Special Primacy Requirements

Q: As a system brings filters on line, at different times, do they need separate timers on each filter

or can they take all readings on the quarter hour (i.e. 3:00, 3:15, 3:30, etc.)?

A: Taking all readings on the quarter hour would meet the intent of the rule. 
IESWTR Implementation Guidance IV-33 June 2001

Q: Is particle counting an adequate substitute for continuous turbidity monitoring?

A: No, particle counting may not be used as a substitute for continuous turbidity monitoring.

However, EPA encourages the use of particle counters for optimization of process control.

Q: Some package plants and/or filters are constructed so that it is not possible to install the

continuous turbidimeters on each filter bed and perform this monitoring. How do you resolve

this issue? 

A: Individual filter monitoring is a requirement of the rule for all Subpart H systems serving 10,000

or more persons that use conventional or direct filtration. This is to ensure public health

protection for the maximum number of people. Configurations which do not allow for such

plumbing, such as a Greenleaf Filter Plant or certain automatic backwash filters, can be

considered one filter and can monitor the combined effluent from the unit every 15 minutes to

determine compliance with the individual filter requirements. Systems which believe that they fall

under this category should consult with the state. However, it is likely that some of these

plants/filters are plumbed such that they can install turbidimeters on individual filters, and

therefore should. 

Q: What if a plant exceeds a turbidity trigger for an individual filter while performing filter to

waste? Does this need to be reported? Is it a violation?

A: The turbidity requirements apply only to water that will become part of the combined filter

effluent of the plant. Filtered wastewater turbidity does not need to be measured or reported and

should not have violations associated with it.

Q: Does each filter need its own turbidimeter or can several filters be connected to one

turbidimeter? 

A: The rule doesn’t preclude the use of a single turbidimeter to measure and record the turbidity of

multiple filters. A state would have to find that this would be an appropriate methodology for

measuring and recording compliance with the individual filter reporting and recordkeeping

requirements. 

Q: When a system exceeds the rule-established individual filter turbidity trigger levels in two

consecutive measurements taken 15 minutes apart, certain corrective actions are required to be

completed within designated time frames. When does the clock start running on those time

limits?

A: The time for completing the necessary corrective actions begins immediately after the second of

the two measurements that exceed the “trigger” level.

Q: How should a system deal with spiked turbidimeter readings for hours (sometimes as many as

12 hours) after the turbidimeter (not the filter it is monitoring) has been cleaned? 

A: EPA believes that the duration of these kinds of spiked readings should normally be a matter of

minutes, not hours. A turbidimeter returning inaccurate readings for more than a few minutes

should be overhauled or replaced. In the event that inaccurate spikes lasted for a longer period of

time, the system would have the option of measuring and recording turbidity at 15 minute

intervals using a bench top turbidimeter until the on-line unit returned to normal.

Q: If a system is required to have a Comprehensive Performance Evaluation (CPE) conducted by

the state or a third party, is the system liable if the state or third party does not conduct the

CPE within 90 days (and the delay is clearly the fault of the state or third party, not the

system)? 

A: If the Comprehensive Performance Evaluation is not completed and the report submitted to the

state within 90 days, a violation is triggered and must be reported. However, the state can

exercise its discretion on what enforcement action is taken. 
June 2001 IV-34 IESWTR Implementation Guidance

When the state chooses to perform the CPE and is unable to do so within the time frame

established by the rule, it has the authority to issue an administrative order that includes the

establishment of a more appropriate compliance schedule.

Q: Is there a limit to the number of CPEs that can be triggered by ongoing compliance problems? 

A: The rule does not specify the number of CPEs that are required in response to turbidity limits that

trigger Section 141.175(b)(4) multiple times for problems with individual filters (turbidity levels of

> 2.0 NTU in two consecutive measurements in each of two consecutive months.) One CPE is

adequate until that CPE has been completed and the appropriate corrective actions taken. The

CPE must be completed within the time limits established by the rule for the initial exceedence.

In cases where the causes of individual filter turbidity problems are not easily and quickly

correctable, the system should consider negotiating with the state to enter into an enforcement

action such as an administrative order with a mutually agreeable set of actions leading to

compliance within an established compliance schedule. Compliance with the administrative order

would limit the system’s liability for having additional CPEs conducted after one had been done

to identify performance limiting factors.

Q: If a turbidity exceedence is caused by a failure of the turbidimeter, does it still have to be

reported?

A: High turbidity readings that are caused by cleaning and purging a turbidimeter, etc. and that are

not indicative of finished water quality do not have to be reported as treatment technique

violations and do not trigger the corrective actions of §141.175(b)(1) - (4). However, the system

must keep a written record of the readings, the cause of the turbidimeter failure, and why the

readings have been deemed inaccurate. When possible, bench top measurements should be made

to provide confirmation of the system’s reasons for deleting and/or replacing measurements.

1.5 Alternative Filtration Technologies

For further information, see the following rule sections:

Citation Part Title

§141.73(d) Filtration

§141.173(b) Filtration

Q: Why are diatomaceous earth and slow sand filters not required to meet the more stringent

turbidity requirements of the IESWTR?

A: Slow sand and DE systems, because of their filtration effectiveness, are assumed to already meet

the 2-log removal for Cryptosporidium under the existing requirements of the SWTR. Therefore,

they are not required to meet more stringent requirements under the IESWTR.

Q: Will a state have to re-evaluate alternative filtration technologies previously approved under

the 1989 SWTR for the purposes of the Cryptosporidium removal requirements of the IESWTR?

A: Yes, states will have to re-evaluate alternative filtration technologies previously approved under

the SWTR in order to determine whether they are capable of 2 log removal of Cryptosporidium

cysts. The rule only requires this re-evaluation for alternative technologies that have been

approved at Subpart H systems serving 10,000 or more people.
IESWTR Implementation Guidance IV-35 June 2001

Q: How will a state approve an alternative filtration technology that reduces the turbidity to levels

that cannot be reliably measured using turbidimeters? How will the PWS determine compliance

with the IESWTR turbidity requirements?

A: States are required by §142.16(g)(iv) to explain how they plan to approve alternative technologies

and establish turbidity performance requirements for such technologies. The state would approve

the above-referenced alternative filtration technology in the same manner it would use for other

technologies that might be less effective in terms of turbidity removal and would then establish

performance standards that would ensure appropriate inactivation/removal of Giardia lamblia

and viruses and removal of Cryptosporidium. For purposes of compliance it would not be

necessary to measure down to the level of actual turbidity removal. It is only necessary to

accurately measure turbidity at the levels established by the state as performance standards for

the technology. The state may require an equally stringent performance requirement such as

frequent integrity testing for membrane systems. 

Q: Can states allow log removal credit for GWUDI systems for natural filtration? Can EPA

develop a criteria for providing credit for natural filtration? 

A: States have the discretion to consider “natural filtration” an alternative technology. Examples

where this might be appropriate are well designed off-stream infiltration galleries and Ranney

collectors. Pursuant to §141.173(b) the system would have to demonstrate to the state that it

consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts, 99.99

percent removal and/or inactivation of viruses, and 99 percent removal of Cryptosporidium

oocysts. The state would then have to establish performance standards that ensure the removal

and inactivation requirements are achieved. 

EPA has not developed guidance for establishing criteria for providing credit for natural filtration.

Q: Are contact absorption clarifiers and dissolved air floatation considered sedimentation in the

conventional filtration process as defined in 141.2?

A: The state has the flexibility to consider these processes as part of the conventional filtration

process. However, once the process has been categorized, the state should be consistent in

implementation for all their systems. If these processes are not classified as part of conventional

filtration, they are considered alternative filtration technologies and must meet the regulatory

provisions that address those technologies.

2.0 General Program Requirements

2.1 Primacy

Q: If the state has a blanket letter from the Attorney General that covers all regulations, does it

have to get a new letter specifically for the IESWTR?

A: Yes. States would not be able to use a letter from the Attorney General that provided certification

of rules not in existence at the time the certification letter was written. The certification would

also have to confirm that there are no state audit laws preventing enforcement of the rules.

Q: Do you need to adopt the PWS definition (if applicable) and obtain administrative penalty

authority in order to receive interim primacy for the IESWTR? 

A: A state is eligible for interim primacy for new regulations provided they have primacy or interim

primacy for all existing regulations. At a time when multiple regulations are being promulgated, a

state qualifies for interim primacy for each rule as the rules are adopted by the state as long as the

time period allowed for adoption (two years plus up to a two year extension, if applicable) has not

expired. For example, even though the CCR was promulgated before the IESWTR, a state can

obtain interim primacy for the IESWTR before the CCR, as long as the deadline to adopt the
June 2001 IV-36 IESWTR Implementation Guidance

CCR has not passed. However, if time period allow for adoption of the CCR has passed and the

state has not adopted the CCR, then the state would not be eligible for interim primacy for the

IESWTR.

Q: Are states going to have to revisit their GWUDI determinations due to the addition of

Cryptosporidium to the definition of GWUDI and the Cryptosporidium removal requirements of

the IESWTR? 

A: No, the processes used by states to identify GWUDI under the existing SWTR would still apply.

When identifying GWUDI, states use a process that considers indicators that cysts might be

present and does not look specifically for cysts. Even though Cryptosporidium oocysts are

different from Giardia cysts, the process is not required to be updated.

Q: Can states “bundle” regulations in their primacy revision package?

A: Yes, states may combine two or more rules in one primacy revision package provided that the

states’ adoption of the rules falls within the statutory two year period and two year extension

period, if applicable.

Q: May a state adopt the IESWTR by reference?

A: Yes, if the state law allows this. However, the state will still need to address the special primacy

requirements which give the state flexibility and discretion in meeting certain requirements.

Q: Our State’s Attorney General does not have the authority to approve regulations. Will this be a

problem for us in terms of obtaining primacy for new rules?

A: EPA does not require the state’s Attorney General to provide approval of regulations adopted for

purposes of the state achieving primacy under these rules. The requirement is for a statement by

the Attorney General, or the primacy agency’s attorney if it has independent legal council, that the

laws and regulations adopted by the state were duly adopted and are enforceable.

2.2 Violations, SDWIS Reporting and SNC Definitions

Q: If a system receives 2 treatment technique violations in 1 month, is that counted as two TT

violations toward SNC?

A: Yes.

Q: How frequently are SNC determinations made? Can a system potentially receive a SNC

designation every month? every quarter? every year?

A: Significant Non-Compliance (SNC) determinations for all rules, including the Interim Enhanced

Surface Water Treatment Rule (IESWTR) and the Stage 1 Disinfectants/Disinfection Byproducts

Rule (DBPR), are made once per quarter, compounding over a rolling four quarter period.

SDWIS guidance states that these determinations are made on the first day of the month

following the end of the quarter which covers the 12 month compliance period which ended the

previous quarter.

Q: The IESWTR does not require systems to gather applicability data. How can you give a system

a M/R violation for not doing so?

A: Failure to gather applicability data is not a federally reportable monitoring and reporting violation.

However, if a system does not conduct applicability monitoring, it must notify the state of this

election, in writing, not later than December 31, 1999 and must (1) begin developing a

disinfection profile not later than March 31, 2000, or (2) obtain state approval to use three years

of existing operational data to create a profile. Failure to profile is a treatment technique violation.

Q: If a system does not profile and is required to, what kind of violation is it?

A: Failure to profile is a treatment technique violation.
IESWTR Implementation Guidance IV-37 June 2001

Q: If a system can receive an SNC designation for failure to conduct disinfection profiling under

the IESWTR, how can the system return to compliance if profiling is a one-time provision?

A: Failure to develop a disinfection profile during the required timeframe is a treatment technique

violation. A system can return to compliance by developing a disinfection profile. Once

completed, the system must retain the disinfection profile data in an acceptable format for review

as part of the sanitary surveys and consult with the state before making a significant change to its

disinfection practice.

2.3 Qualified Operators

Q: There is a requirement of the SWTR that the systems be operated by qualified personnel. What

if the system has a membrane plant that is not operated on a full time basis? EPA has not

mandated the number of hours in a operating cycle and systems have been installing membrane

plants to prevent being required to have a full-time operator. 

A: Both the Surface Water Treatment Rule and the Stage 1 Disinfectants/Disinfection Byproducts

Rule require regulated systems to be operated by qualified personnel who meet the requirements

specified by the state and are included in a state register of qualified operators. The rules do not,

however, address the amount of time qualified operators are required to spend on site at the plant.

EPA believes that this type of determinations should be left to the states’ discretion.

Q: Who in the state must maintain the list of qualified operators? Is it acceptable if the Public

Water Supply Supervision Program (PWSS) does not maintain the list, but another agency in

the state does? 

A: Yes, it is acceptable for a state agency other than the primacy agency to maintain the state’s

register of qualified operators. It is essential, however, for the PWSS Program to have access to

that register.
June 2001 IV-38 IESWTR Implementation Guidance

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