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EPA Publishes Proposed Perchlorate Drinking Water Regulation

On Thursday, 5/23, EPA published the pre-publication version of the proposed perchlorate drinking water regulation. EPA is asking for comments on a proposed National Primary Drinking Water Regulation (NPDWR) for perchlorate to establish a Maximum Contaminant Level (MCL) and a health-based Maximum Contaminant Level Goal (MCLG) at 56 micrograms per liter. For historical reference, perchlorate was listed on the First Contaminant Candidate List (CCL1) in 1998 and listed on the First Unregulated Contaminant Monitoring Rule (UCMR1) in 1999.

In addition, the Agency is seeking comment on three alternative regulatory options:

  • An MCL and MCLG for perchlorate set at 18 micrograms per liter.
  • An MCL and MCLG for perchlorate set at 90 micrograms per liter.
  • Withdrawal of the Agency’s 2011 determination to regulate perchlorate in drinking water, which was a reversal of the 2008 preliminary determination to not regulate perchlorate.

EPA is requesting comment on all relevant aspects of the proposed rule but is especially interested in the perchlorate monitoring and reporting requirements for public water systems, and any implementation issues and the potential initial monitoring requirements are of particular interest to ASDWA’s members. EPA is also requesting comment on its methodology for deriving the MCLG, the underlying assumptions and analysis of its cost and benefit estimates, and other specific items listed in the proposed rule.

If you are interested in this regulation, you should submit comments to EPA. EPA will accept public comment on the proposal for 60 days after publication in the Federal Register via http://www.regulations.gov [Docket ID No. EPA-HQ-OW-2018-0780]. Based on an estimated Federal Register publication at the end of May, comments would be due by the end of July.