1

Fact Sheet: Announcement of the Results of EPA’s Review of

Existing Drinking Water Standards and Request for Public

Comment

1. What is the Environmental Protection Agency (EPA) announcing?

The Agency is announcing its preliminary revise/not revise decisions for 68 chemical

National Primary Drinking Water Regulations (NPDWRs) and the Total Coliform Rule (TCR). 

EPA is requesting public comment on these preliminary determinations, the data and information

used to support these determinations, and on the protocol the Agency used to conduct the review. 

As a result of the review, the Agency preliminarily believes that the 68 chemical NPDWRs

remain appropriate at this time, and that the TCR should be revised. However, the Agency notes

that there are a number of scientific assessments either planned or underway that may indicate

the need for further revisions for a subset of these 68 regulations in the future.

2. Why did EPA review these NPDWRs?

Under the Safe Drinking Water Act (SDWA), EPA must periodically review existing 

NPDWRs and, if appropriate, revise them. This requirement is contained in Section 1412(b)(9)

of SDWA, as amended in 1996, which reads:

The Administrator shall, not less often than every 6 years, review and revise, as appropriate,

each national primary drinking water regulation promulgated under this title. Any revision

of a national primary drinking water regulation shall be promulgated in accordance with

this section, except that each revision shall maintain, or provide for greater, protection of

the health of persons.

3. What NPDWRs are covered by this action?

The Six-Year Review process only applies to existing national primary drinking water

regulations (i.e., currently regulated contaminants). Unregulated contaminants, such has those

being evaluated by the Contaminant Candidate List (CCL) are not covered by the Six-Year

Review. The current 1996-2002 review addresses NPDWRs promulgated prior to 1997 (referred

to as pre-1997 NPDWRs), with the exception of those regulations that are the subject of recent

or ongoing rulemaking activity (e.g., arsenic, radionuclides, disinfection byproducts, and most

microbiological NPDWRs). EPA will review NPDWRs promulgated after 1997 at a later date.

4. How did EPA review the pre-1997 NPDWRs?

The primary goal of the Six-Year Review was to identify, prioritize and target candidates

for regulatory revision that are most likely to result in an increased level of public health

protection and/or a substantial cost savings while maintaining the level of public health
2

protection. To address this goal, EPA developed a systematic approach, or protocol, for the

review of existing NPDWRs. EPA developed the protocol in consultation with the National

Drinking Water Advisory Council (NDWAC) and other stakeholders. The protocol focused on

several key elements that were intended to identify NPDWRs for which there is a health or

technology basis for revising the NPDWR. The review relied upon an evaluation of relevant,

new information for the following key technical elements: health effects, analytical methods

improvements, treatment technology effectiveness, other potential regulatory changes,

occurrence and exposure data, and potential economic impacts. Figure 1 gives a general

overview of the protocol used to make the revise/not revise decisions for the pre-1997 NPDWRs.
3

Yes

No

Does the review suggest possible changes

in MCLG/MCL/TT and or other

regulatory revisions?

Is a significant gain in

public health protection or significant

cost savings likely to occur?

No Revision 

at this time

(68 total)

Candidate 

for Revision

(1)

Are the data sufficient to support

 regulatory revision ?

NPDWR remains appropriate

after data/information review

(17)

Negligible gain in 

public health protection

 and/or cost savings

(12)

Data gaps - determine

research needs

(3)

Yes

No

Pending health

risk assessment 

(36)

Is a health risk assessment

in process/planned?

Yes

No

Yes

No

In-depth Technical Analysis

New risk assessment, methods feasibility, 

treatment effectiveness, occurrence and exposure

and economic implications.

* Publish FR notice with preliminary revise/not decisions.

* Review Public Comments and consider revising decisions

in context of new information.

* Publish FR notice with final list of NPDWRs to be revised.

NPDWRs under review

Initial Technical Review

Health Effects, analytical methods and 

treatment feasibility, and other regulatory 

revisions

Figure 1. Overview of the Protocol for the Revise/Not Revise Decision
4

5. What are the preliminary revise/not revise decisions?

Based on its review, EPA believes it is appropriate to revise the Total Coliform Rule. 

EPA believes none of the 68 chemical NPDWRs should be revised at this time for one of

the following reasons:

(A) Pending health risk assessments - EPA identified 36 NPDWRs for which the Agency is

in the process of performing health risk assessments. These assessments are not expected

to be complete in time for EPA to make its final revise/not revise decisions in August

2002 time frame. The Agency does not believe it is appropriate to consider revisions to

these NPDWRs while the health risk assessments are in process. When the assessment

for an NPDWR is completed, EPA will review the updated risk assessment during the

next review cycle. 

(B) Remains appropriate after data/information review - EPA identified 17 NPDWRs for

which the outcome of the review indicates that the current regulatory requirement

remains appropriate. Any new information available to the Agency supports retaining

the current regulatory requirements.

(C) Negligible gain in public health protection and/or cost savings - EPA identified 12

NPDWRs that have new health, technological, or other information that indicates a

potential revision to a maximum contaminant level goal (MCLG) and/or maximum

contaminant level (MCL); however, the Agency believes any potential revision would

result in a minimal gain in the level of public health protection and/or provide negligible

opportunity for significant cost-savings. EPA, therefore, does not believe revisions are

warranted at this time.

(D) Data gaps - EPA identified 3 NPDWRs that have data gaps or research needs which must

be addressed before EPA can make definitive regulatory decisions. When the data gaps

have been resolved, EPA plans to consider the results in the next review cycle.

The Agency’s commitment to completing ongoing or planned assessments and filling

data gaps reflects its commitment to sound science and its desire to make regulatory information

based upon the best available information and data. Table 1 provides a more detailed list of the

69 NPDWRs and the placement of each NPDWR with respect to the revise/not revision decision.

6. Will EPA consider reviewing any NPDWRs before the next review cycle?

If the result of any health risk assessment currently in process or the resolution of data

gaps/research needs indicate that significant or compelling new information is available that will

change the basis for an NPDWR, the Agency may decide to accelerate the review schedule.
5

Table 1: Preliminary Revise/Not Revise Decisions for the 68 Chemical NPDWRs and TCR

Not

Appropriate

for Revision

at this Time

Risk assessment in process: 

chemical currently

undergoing an EPA health

risk assessment; 

includes the three initiated as

a result of this review 1

(36 NPDWRs)

Acrylamide (TT)2 (2004 / 2005) 

Alachlor (2002 / 2003)

Antimony (2002 / 2003)

Asbestos (2004 / 2005)

Atrazine (2002)

Benzo[a]pyrene (2002 / 2003)

Cadmium (2002 / 2003)

Carbofuran (2002 / 2003)

Carbon tetrachloride (2002 / 2003)

Copper (TT) 2

 (2002 / 2003)

Cyanide (2004 / 2005)1

2,4-D (2003 / 2004)

1,2-Dichlorobenzene (2002 / 2003) 

1,4-Dichlorobenzene (2002 / 2003)

1,2-Dichloroethane (2002 / 2003)

1,1-Dichloroethylene (2002 / 2003)

Di(2-ethylhexyl)adipate (2003 / 2004)1

Di(2-ethylhexyl)phthalate (2002 / 2003)

Diquat (2002)

Endothall (2003 / 2004)

Ethylbenzene (2002 / 2003)

Ethylene dibromide (2002 / 2003)

Glyphosate (2002 / 2003)

Lindane (2003 / 2004)

Methoxychlor (2002 / 2003)

Pentachlorophenol (2002 / 2003)

Polychlorinated biphenyls (2002 / 2003)

Simazine (2003 / 2004)

Styrene (2002 / 2003)

2,3,7,8-TCDD (Dioxin) (2002 / 2003)

Tetrachloroethylene (2002 / 2003)

Thallium (2004 / 2005)1

Toluene (2002 / 2003)

1,1,1-Trichloroethane (2003 / 2004)

Trichloroethylene (2002 / 2003)

Xylenes (2002 / 2003)

NPDWR remains appropriate

after data/information review 

(17 NPDWRs)

Barium

Dalapon

cis-1,2-Dichloroethylene

trans-1,2-Dichloroethylene

Dinoseb

Endrin

Epichlorohydrin (TT)2

Hexachlorocyclopentadiene

Lead (TT)2

Mercury 

Monochlorobenzene

Nitrate

Nitrite

Selenium

2,4,5-TP (Silvex)

1,2,4-Trichlorobenzene

Vinyl chloride

New

information,

but no revision

recommended

because:

Negligible

gain in health

protection

(12 NPDWRs)

Benzene

Beryllium

Chlordane

1,2-Dibromo-3-chloropropane

1,2-Dichloropropane

Heptachlor

Heptachlor epoxide

Hexachlorobenzene

Oxamyl

Picloram

Toxaphene

1,1,2-Trichloroethane

Information

gaps

(3 NPDWRs)

Chromium

Dichloromethane3 Fluoride4

Candidates 

for Revision

Based on other 

regulatory revisions 

(1 NPDWR)

Total Coliform Rule (TCR)

1

 New information was identified for cyanide, di(2-ethylhexyl)adipate, and thallium as a result of the six-year health effects

review. The Agency has initiated new risk assessments for these three contaminants.

2

 TT designates treatment-technique rules (i.e., those NPDWRs for which a treatment technique has been set in place of an MCL).

3

 Preliminary analysis indicates that there may be an opportunity for improvement in public health protection if the PQL/MCL

were lowered. Additional data are needed to support such a change.

4

 EPA plans to ask NAS to update the risk assessment for fluoride.
United States Environmental Protection Agency March 2002

Office of Water (4607M) EPA 815-F-02-002

www.epa.gov/water 6

7. What are the next steps?

EPA plans to hold a 60-day public comment period after the publication of the Federal

Register with the preliminary revise/not revise decisions. During the public comment period, the

Agency also intends to hold a stakeholder meeting and consult with the Science Advisory Board

(SAB). After taking public comments into consideration, the Agency plans to publish its final

revise/not revise decisions for the 69 pre-1997 NPDWRs in the Federal Register in the August

2002 time frame. 

8. Where can I find more information about this notice and the Six-Year Review?

For general information on the Six-Year Review, please visit the EPA Safewater Web

site at http://www.epa.gov/safewater or contact the Safe Drinking Water Hotline at 1-800-

426-4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding Federal

holidays, from 9:00 a.m. to 5:30 p.m. Eastern Time. In addition to this fact sheet, the following

documents are electronically available to the public at EPA's web site on the Six-Year Review:

(A) The Federal Register announcing the preliminary revise/not revise decisions for the SixYear Review; and 

(B) The technical support documents for the Six-Year Review:

< EPA's Protocol for the Review of Existing National Primary Drinking Water

Regulations (EPA 815-D-02-004)

< Six-Year Review - Chemical Contaminants: Health Effects (EPA 822-R-02-001)

< Analytical Feasibility Support Document for the Six-Year Review of Existing

National Primary Drinking Water Regulations (EPA 815-D-02-002)

< Water Treatment Technology Feasibility Support Document (EPA 815-D-02-001)

< Consideration of Other Regulatory Revisions for Chemical Contaminants in

Support of the Six-Year Review of National Primary Drinking Water Regulations

(EPA 815-D-02-003)

< Occurrence Estimation Methodology and Occurrence Findings Report for the SixYear Regulatory Review (EPA 815-D-02-005)

< Occurrence Summary and Use Support Document for the Six-Year Regulatory

Review (EPA 815-D-02-006)

 For a hard copy of this fact sheet (EPA 815-F-02-002), the Federal Register notice,

and/or any of the Six-Year supporting documents, please contact EPA’s Water Resource Center

at 1-800-832-7828.