As required by the Safe Drinking Water Act (SDWA), the EPA has completed its third 6-year review of existing drinking water standards and announced that eight standards are candidates for regulatory revisions.
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Formally called National Primary Drinking Water Regulations (NPDWRs), the standards apply to regulated contaminants/parameters. The current review specifically focused on the 76 NPDWRs promulgated before August 2008. The EPA says it determined that 68 of these NPDWRs remain appropriate and do not need to be revised. The eight NPDWRs in line for revisions are chlorite, cryptosporidium, giardia lamblia, haloacetic acids (HAA5), heterotrophic bacteria, legionella, total trihalomethanes (TTHM), and viruses. These contaminants are regulated under five national rules: the Stage 1 and the Stage 2 Disinfectants and Disinfection By-Products rules, the Surface Water Treatment Rule, the Interim Enhanced Surface Water Treatment Rule, and the Long-Term 1 Enhanced Surface Water Treatment Rule.
In addition to the 76 NPDWRs, the Agency reported that 12 other NPDWRs did not need a detailed review because of recent, ongoing, or pending regulatory actions. These NPDWRs include lead, copper, trichloroethylene (TCE), and tetrachloroethylene (PCE).
Review process
As stated by the EPA, the detailed reviews were conducted according to the EPA Protocol for the Third Review of Existing National Primary Drinking Water Regulations. This document is a descendent of the process the Agency used for the first and second 6-year reviews and is based on recommendations made by the National Drinking Water Advisory Council.
The detailed review subjects each NPDWR to a series of questions. For example: Is the NPDWR subject to a recent or ongoing action? Is a health effects assessment for the NPDWR ongoing or planned? If the answers are “no,” the review proceeds to the next series of questions, including: Is there new information to suggest that changes to regulations (e.g., maximum contaminant level (MCL) or treatment technique) are possible? Are there data to support regulatory revision? Are there meaningful opportunities to reduce risks to people served by public water systems? If the answers to these questions are “yes”—as is the case for the eight NPDWRs—the NPDWR becomes a candidate for revision.
Expedited reviews possible
The majority of the 68 NPDWRs were found not to be candidates for revision because no new information is available, the NPDWRs remains appropriate after detailed review, the NPDWRs are low priority, and/or there are no meaningful opportunities to reduce risks to the public.
Also, 9 of the 68 NPDWRs have been nominated for heath assessments, specifically, cadmium, chromium, di(2-ethylhexyl) phthalate (DEHP), ethylbenzene, glyphosate, polychlorinated biphenyls (PCBs), radium, simazine, and uranium. The EPA says that if health assessments for these contaminants uncover “compelling new information” that will change the basis for an NPDWR, the Agency may decide to accelerate the review in advance of the next scheduled 6-year review.
More information on EPA’s 6-year review of the NPDWRs is here.
The request for public comment on the eight NPDWRs identified as candidates for revision was published in the January 11, 2017, FR.