Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Six-Year Review of Drinking Water Standards

Six-Year Review 1 of Drinking Water Standards

In July 2003, EPA announced the review results for the first Six-Year Review (called the Six-Year Review 1). EPA reviewed 69 national primary drinking water regulations (NPDWRs) that were established prior to 1997. These 69 NPDWRs include 68 chemical NPDWRs and the Total Coliform Rule (TCR). Based on the Agency's review, as well as the public comments received and other new information, EPA found that it was appropriate to revise the Total Coliform Rule (TCR). EPA found that it was not appropriate to revise the 68 chemical NPDWRs at that time.

On this page:

Results Summary
Federal Register Notices and Fact Sheet
Support Documents for EPA's First Review of Existing Drinking Water Standards
 

Summary of Six-Year Review 1 Results

Learn more about the drinking water contaminants listed below

Summary of Review Outcomes

Regulated Contaminants

Not Appropriate for Revision at this Time

Risk assessment in process1:
chemical currently undergoing an EPA health risk assessment;
includes the three initiated as a result of this review
(34 NPDWRs)
Acrylamide
Alachlor
Antimony
Asbestos
Atrazine
Benzo[a]pyrene
Cadmium                  
Carbofuran
Carbon tetrachloride
Copper             
Cyanide             
2,4-D (2,4-Dichlorophenoxyacetic acid)
1,2-Dichlorobenzene
1,4-Dichlorobenzene
1,2-Dichloroethane
Di(2-ethylhexyl)adipate
Di(2-ethylhexyl)phthalate
Diquat
Endothall
Ethylbenzene
Ethylene dibromide
Glyphosate
Methoxychlor
Pentachlorophenol
Polychlorinated biphenyls
Simazine
Styrene
2,3,7,8-TCDD (Dioxin)
Tetrachloroethylene
Toluene
1,1,1-Trichloroethane
Trichloroethylene
Xylenes

NPDWR remains appropriate after data/information review(16 NPDWRs)

Barium
Dalapon
cis-1,2-Dichloroethylene
trans-1,2-Dichloroethylene
Dinoseb
Endrin
Epichlorohydrin
Hexachlorocyclopentadiene
Mercury
Monochlorobenzene
Nitrate
Nitrite
Selenium
2,4,5-TP (Silvex)
1,2,4-Trichlorobenzene
Vinyl chloride

New information, but no revision recommended because:

Low priority
(14 NPDWRs)

Benzene
Beryllium
Chlordane
1,2-Dibromo-3-chloropropane
1,1-Dichloroethylene
1,2-Dichloropropane
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Lindane
Oxamyl
Picloram
Toxaphene
1,1,2-Trichloroethane

Information gaps
(4 NPDWRs)

Chromium
Dichloromethane
Fluoride
Lead

Candidate for Revision

Based on review of "other regulatory provisions" (1 NPDWR)

Total Coliform Rule (TCR)

1. As of December 31, 2002, EPA was conducting or had scheduled a detailed review of health effects information.


Federal Register Notices and Fact Sheet

  • Federal Register Notice - Final Completion
    • National Primary Drinking Water Regulations; Announcement of Completion of EPA's Review of Existing Drinking Water Standards  July 18, 2003: (Volume 68, Number 138)
  • ​Federal Register Notice - Proposed Results and Comment Period
    • National Primary Drinking Water Regulations; Announcement of the Results of EPA's Review of Existing Drinking Water Standards and Request for Public Comment  April 17, 2002: (Volume 67, Number 74)
  • Fact Sheet: Six-Year Review 1
    • Read the Fact Sheet

Support Documents for EPA’s First Review of Existing Drinking Water Standards

  • Read the support documents

Six-Year Review of Drinking Water Standards

  • Statutory Requirements
  • Learn About Six-Year Review Elements
  • Six-Year Review 4
  • Six-Year Review 3
  • Six-Year Review 2
  • Six-Year Review 1
Contact Us About the Six Year Review of Drinking Water Standards
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on May 15, 2025
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.