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Six-Year Review 3 of Drinking Water Standards


Overview

EPA has announced the review results for the Agency’s third Six-Year Review (called Six-Year Review 3). Based on the Agency's detailed review of 76 national primary drinking water regulations (NPDWRs), EPA concluded that eight NPDWRs are candidates for regulatory revision. The eight candidates are Chlorite, Cryptosporidium (under the SWTR, IESWTR and LT1), Haloacetic acids, Heterotrophic Bacteria, Giardia lamblia, Legionella, Total Trihalomethanes, and Viruses (under the SWTR). These eight NPDWRs are included in the:

EPA determined that for the contaminants regulated under these rules there is new information on health effects, treatment technologies, analytical methods, occurrence and exposure, implementation and/or other factors that provide a health or technical basis to support a regulatory revision that will improve public health protection. This announcement is not a regulatory decision. Instead, it initiates a process that will involve more detailed analyses of health effects, analytical and treatment feasibility, occurrence, benefits, costs and other regulatory matters relevant to deciding whether a rulemaking to revise a regulation should be initiated. EPA will be seeking public comment and information to help inform future regulatory revisions for the eight candidates.

In addition to the 76 NPDWRs, this review included 12 other NPDWRs that did not need a detailed review because of recent, ongoing, or pending regulatory actions. Those contaminants having recent or ongoing regulatory actions are: lead, copper, total coliforms (under ADWR and RTCR), E. coli, and eight carcinogenic volatile organic compounds (cVOCs).


Summary of Six-Year Review 3 Results

Learn more about the drinking water contaminants listed below

Summary of Review Outcomes Regulated Contaminants

Helpmaximum contaminant levelThe highest level of a contaminant that is allowed in drinking water as delineated by the National Primary Drinking Water Regulations. These levels are based on consideration of health risks, technical feasibility of treatment, and cost-benefit analysis.

1. Contaminants nominated for Integrated Risk Information System (IRIS) assessments per Six-Year Review Protocol.

2. Long Term 2 Enhanced Surface Water Treatment Rule (LT2), Filter Backwash Recyling Rule (FBRR), and Ground Water Rule (GWR) also identified as not appropriate for revision at this time. See Section VI.B.4 of the Federal Register notice for additional information on the results of EPA’s review of these regulations.
 
Not Appropriate
for Revision
at this Time2
Due to Recently Completed, Ongoing,
or Pending Regulatory Action
1,2-Dichloroethane (Ethylene dichloride)
1,2-Dichloropropane
Benzene
Carbon Tetrachloride
Copper
Dichloromethane (Methylene chloride)
E. coli
Lead 
Tetrachloroethylene (PCE)
Total coliforms (under ADWR and RTCR)
Trichloroethylene (TCE)
Vinyl chloride
Health effects assessment in process (as of December 2015)
or contaminant nominated for health assessment
Alpha/photon emitters
Arsenic
Atrazine
Benzo(a)pyrene (PAHs)
Beta/photon emitters
Cadmium1
Chromium
Di(2-ethylhexyl)phthalate (DEHP)1
Ethylbenzene
Glyphosate
Mercury1
Nitrate1
Nitrite1
o-Dichlorobenzene1
p-Dichlorobenzene1
Polychorinated biphenyls (PCBs)
Radium
Simazine
Uranium1
No new information, NPDWR remains
appropriate after review
1,2-Dibromo-3-chloropropane (DBCP) 
2,4,5 -TP (Silvex)
Antimony
Asbestos
Bromate
Chloramines (under D/DBPR)
Chlorine (under D/DBPR)
Chlorine dioxide
Chlorobenzene (monochlorobenzene)
Dalapon
Di(2-ethylhexyl)adipate (DEHA)
Dinoseb
Endrin
Ethylene dibromide
Pentachlorophenol
Thallium
trans-1,2-Dichloroethylene
Turbidity
Low priority and/or no
meaningful opportunity
1,1,1-Trichloroethane
1,1,2-Trichloroethane
1,1-Dichloroethylene
1,2,4-Trichlorobenzene
2,3,7,8-TCDD (Dioxin)
2,4-D
Acrylamide
Alachlor
Barium
Beryllium
Carbofuran
Chlordane
cis-1,2-Dichloroethylene
Cyanide
Diquat
Endothall
Epichlorohydrin
Fluoride
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorocyclopentadiene
Lindane
Methoxychlor
Oxamyl (Vydate)
Picloram
Selenium
Styrene
Toluene
Toxaphene
Xylenes
Candidate for Revision New Information
Chlorite
Cryptosporidium (under SWTR, IESWTR, LT1)
Giardia lamblia
Haloacetic Acids (HAA5)
Heterotrophic Bacteria
Legionella
TTHM
Viruses (under SWTR)

Federal Register Notice and Frequent Questions About Six-Year Review 3

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Fact Sheet, Support Documents and Occurrence Data for EPA's Third Six-Year Review of Existing Drinking Water Standards