National Primary Drinking Water Regulations; Announcement of the Results of EPA's Fourth Review of Existing Drinking Water Standards

<RULE> ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 141</CFR> <DEPDOC>[EPA-HQ-OW-2023-0572; FRL 7946-01-OW]</DEPDOC> <SUBJECT>National Primary Drinking Water Regulations; Announcement of the Results of EPA's Fourth Review of Existing Drinking Water Standards</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Results of regulatory review. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Safe Drinking Water Act (SDWA) requires the U.S. Environmental Protection Agency (EPA or the agency) to conduct a review every six years of existing national primary drinking water regulations (NPDWRs) and determine which, if any, are appropriate for revision. The purpose of the review, called the Six-Year Review, is to evaluate available information for regulated contaminants to determine if any new information on health effects, treatment technologies, analytical methods, occurrence, exposure, implementation, and/or other factors provides a basis to support a regulatory revision that would improve or strengthen public health protection. While EPA has recently completed several significant revisions to existing regulations and other regulatory revisions are currently underway, based on this periodic review of all NPDWRs, there are no additional candidates for regulatory revision at this time. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> July 23, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> EPA is not accepting public comment on the review results. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Samuel Hernandez, Environmental Protection Agency, Office of Ground Water and Drinking Water, Standards and Risk Management Division, (Mail Code 4607M), 1200 Pennsylvania Avenue NW, Washington, DC 20460; telephone number: (202) 564-1735; email address: <E T="03">hernandez.samuel@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <E T="03">Abbreviations and acronyms:</E> The following acronyms and abbreviations are used throughout this document. <EXTRACT> <FP SOURCE="FP-1">2,4-D—2,4-Dichlorophenoxyacetic acid</FP> <FP SOURCE="FP-1">ADWR—Aircraft Drinking Water Rule</FP> <FP SOURCE="FP-1">BAT—Best Available Technology</FP> <FP SOURCE="FP-1">CFR—Code of Federal Regulations</FP> <FP SOURCE="FP-1">CVOC—Carcinogenic Volatile Organic Contaminant</FP> <FP SOURCE="FP-1">CWS—Community Water System</FP> <FP SOURCE="FP-1">DBCP—1,2-Dibromo-3-Chloropropane</FP> <FP SOURCE="FP-1">DBP—Disinfection Byproduct</FP> <FP SOURCE="FP-1">DEHA—Di(2-ethylhexyl)adipate</FP> <FP SOURCE="FP-1">DEHP—Di(2-ethylhexyl)phthalate</FP> <FP SOURCE="FP-1">EPA—U.S. Environmental Protection Agency</FP> <FP SOURCE="FP-1">EQL—Estimated Quantitation Level</FP> <FP SOURCE="FP-1">FBRR—Filter Backwash Recycling Rule</FP> <FP SOURCE="FP-1">GWR—Ground Water Rule</FP> <FP SOURCE="FP-1">HAA5—Haloacetic Acids (five) (sum of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid)</FP> <FP SOURCE="FP-1">ICR—Information Collection Request</FP> <FP SOURCE="FP-1">IRIS—Integrated Risk Information System</FP> <FP SOURCE="FP-1">LT2—Long-Term 2 Enhanced Surface Water Treatment Rule</FP> <FP SOURCE="FP-1">MCLG—Maximum Contaminant Level Goal</FP> <FP SOURCE="FP-1">MCL—Maximum Contaminant Level</FP> <FP SOURCE="FP-1">MDBP—Microbial and Disinfection Byproduct</FP> <FP SOURCE="FP-1">MDL—Method Detection Limit</FP> <FP SOURCE="FP-1">MRDLG—Maximum Residual Disinfectant Level Goal</FP> <FP SOURCE="FP-1">MRDL—Maximum Residual Disinfectant Level</FP> <FP SOURCE="FP-1">MRL—Minimum Reporting Level</FP> <FP SOURCE="FP-1">NAS—National Academy of Sciences</FP> <FP SOURCE="FP-1">NCWS—Non-Community Water System</FP> <FP SOURCE="FP-1">NDWAC—National Drinking Water Advisory Council</FP> <FP SOURCE="FP-1">NPDWR—National Primary Drinking Water Regulations</FP> <FP SOURCE="FP-1">NRC—National Research Council</FP> <FP SOURCE="FP-1">NTP—National Toxicology Program</FP> <FP SOURCE="FP-1">PCBs—Polychlorinated biphenyls</FP> <FP SOURCE="FP-1">PCE—Tetrachloroethylene</FP> <FP SOURCE="FP-1">PQL—Practical Quantitation Limit</FP> <FP SOURCE="FP-1">PT—Proficiency Testing</FP> <FP SOURCE="FP-1">PWS—Public Water System</FP> <FP SOURCE="FP-1">RfD—Reference Dose</FP> <FP SOURCE="FP-1">RSC—Relative Source Contribution</FP> <FP SOURCE="FP-1">RTCR—Revised Total Coliform Rule</FP> <FP SOURCE="FP-1">SDWA—Safe Drinking Water Act</FP> <FP SOURCE="FP-1">SDWIS—Safe Drinking Water Information System</FP> <FP SOURCE="FP-1">SWTR—Surface Water Treatment Rule</FP> <FP SOURCE="FP-1">TCDD—Tetrachlorodibenzo-p-dioxin</FP> <FP SOURCE="FP-1">TCE—Trichloroethylene</FP> <FP SOURCE="FP-1">TCR—Total Coliform Rule</FP> <FP SOURCE="FP-1">TNCWS—Transient Non-Community Water System</FP> <FP SOURCE="FP-1">TTHM—Total Trihalomethanes (sum of four THMs: chloroform, bromodichloromethane, dibromochloromethane, and bromoform)</FP> <FP SOURCE="FP-1">TT—Treatment Technique</FP> <FP SOURCE="FP-1">USGS—U.S. Geological Survey</FP> </EXTRACT> <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. General Information</FP> <FP SOURCE="FP1-2">A. Does this action apply to me?</FP> <FP SOURCE="FP1-2">B. How can I get copies of this document and other related information?</FP> <FP SOURCE="FP-2">II. Statutory Requirements for the Six-Year Review</FP> <FP SOURCE="FP-2">III. Regulations Included in the Six-Year Review 4</FP> <FP SOURCE="FP-2">IV. EPA's Protocol for Reviewing the NPDWRs Included in This Action</FP> <FP SOURCE="FP1-2">A. What was EPA's review process?</FP> <FP SOURCE="FP1-2">B. How did EPA conduct the review of the NPDWRs?</FP> <FP SOURCE="FP1-2">1. Initial Review</FP> <FP SOURCE="FP1-2"> 2. Health Effects </FP> <FP SOURCE="FP1-2">3. Analytical Feasibility</FP> <FP SOURCE="FP1-2">4. Occurrence and Exposure Analysis</FP> <FP SOURCE="FP1-2">5. Treatment Feasibility</FP> <FP SOURCE="FP1-2">6. Risk-Balancing</FP> <FP SOURCE="FP1-2">7. Other NPDWR Revisions</FP> <FP SOURCE="FP-2">V. Results of EPA's Review of NPDWRs</FP> <FP SOURCE="FP1-2">A. Overview of Six-Year Review 4 Results</FP> <FP SOURCE="FP1-2">B. Chemical Phase Rules/Radionuclides Rules</FP> <FP SOURCE="FP1-2">1. Key Review Outcomes</FP> <FP SOURCE="FP1-2">2. Summary of Review Results</FP> <FP SOURCE="FP1-2">3. Select NPDWRs with New Information Not Appropriate for Revision</FP> <FP SOURCE="FP1-2">C. Microbial Contaminants Regulations</FP> <FP SOURCE="FP-2">VI. References</FP> </EXTRACT> <HD SOURCE="HD1">I. General Information</HD> <HD SOURCE="HD2">A. Does this action apply to me?</HD> This action itself does not impose any requirements on individual people or entities. Instead, it notifies interested parties of EPA's review of existing national primary drinking water regulations (NPDWRs) and its conclusions about which of these NPDWRs may warrant regulatory revisions at this time. The Six-Year Review is not a final regulatory decision to revise or not revise an NPDWR, but rather a planning process that involves more detailed analyses of factors relevant to deciding whether a rulemaking to revise an NPDWR should be initiated. <HD SOURCE="HD2">B. How can I get copies of this document and other related information?</HD> 1. <E T="03">Docket.</E> EPA has established a docket for this action under Docket ID No. EPA-HQ-OW-2023-0572. Publicly available docket materials are available electronically on <E T="03">www.regulations.gov</E> or in hard copy at the EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution Ave. NW, Washington, DC. The Docket Center's hours of operations are 8:30 a.m. to 4:30 p.m., Monday through Friday (except Federal Holidays). For further information on the EPA Docket Center services and the current status see <E T="03">: https://www.epa.gov/dockets.</E> 2. <E T="03">Electronic Access.</E> You may access this <E T="04">Federal Register</E> document electronically from <E T="03">https://www.federalregister.gov.</E> <HD SOURCE="HD1">II. Statutory Requirements for the Six-Year Review</HD> Under the Safe Drinking Water Act (SDWA), as amended in 1996, EPA must periodically review existing NPDWRs and, if appropriate, revise them. Section 1412(b)(9) of the SDWA states: “The Administrator shall, not less often than every six 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.” Pursuant to the 1996 SDWA Amendments, EPA completed and published the results of its first Six-Year Review (Six-Year Review 1) on July 18, 2003 (68 FR 42908, USEPA, 2003), the second Six-Year Review (Six-Year Review 2) on March 29, 2010 (75 FR 15500, USEPA, 2010a) and the third Six-Year Review (Six-Year Review 3) on January 11, 2017 (82 FR 3518, USEPA, 2017a). During the Six-Year Review 1, EPA identified the Total Coliform Rule (TCR) as a candidate for revision. <SU>1</SU> <FTREF/> In Six-Year Review 2, EPA identified four NPDWRs corresponding to acrylamide, epichlorohydrin, tetrachloroethylene (PCE), and trichloroethylene (TCE) as candidates for revision. In Six-Year Review 3, eight NPDWRs were listed as candidates for revision, including: chlorite, <E T="03">Cryptosporidium</E> (under SWTRs), <E T="03">Giardia lamblia,</E> haloacetic acids (HAA5), heterotrophic bacteria, <E T="03">Legionella,</E> total trihalomethanes (TTHM), and viruses (under SWTRs). EPA also announced that the NPDWRs for acrylamide and epichlorohydrin were no longer candidates for revision due to low opportunity for further reduction of public health risk through regulatory revision (82 FR 3525, USEPA, ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 165k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━