EPA Will Not Set Perchlorate MCL (June 17, 2020)

This morning the US Environmental Protection Agency (EPA) posted a pre-publication Federal Register notice (perchlorate_Fed Reg_prebpub_2020-06-18) indicating that the Agency will not establish a Maximum Contaminant Level (MCL) for perchlorate. Statement below is taken from EPA’s press release:

“WASHINGTON (June 18, 2020) — Today, the U.S. Environmental Protection Agency (EPA) issued a final action regarding the regulation of perchlorate under the Safe Drinking Water Act (SDWA). Considering the best available science and the proactive steps that EPA, states and public water systems have taken to reduce perchlorate levels, the agency has determined that perchlorate does not meet the criteria for regulation as a drinking water contaminant under the SDWA. Therefore, the agency is withdrawing the 2011 regulatory determination and is making a final determination to not issue a national regulation for perchlorate at this time.”

EPA Press Release:


E&E News:



In February 2011 EPA made a determination to regulate perchlorate in drinking water.  In October 2016, the US District Court for the Southern District of New York entered a consent decree (with EPA and the Natural Resources Defense Council, NRDC) requiring EPA to “sign for publication in the Federal Register” a proposed Maximum Contaminant Level Goal (MCLG) and NPDWR by the end of October 2018.  The consent decree requires EPA to publish a final MCLG and NPDWR by December 19, 2019.

On June 26, 2019 EPA proposed the perchlorate MCLG and MCL at 56 ppb.   The 60-day public comment period closed on August 26, 2019.  In addition, EPA requested public comment on the following three alternatives:

  1. MCLG and MCL at 18 ppb.
  2. MCLG and MCL at 90 ppb
  3. Withdrawing EPA’s February 2011 determination to regulate perchlorate in drinking water “…based on new information that indicates that perchlorate does not occur in public water systems with a frequency and at levels of public health concern and there may not be a meaningful opportunity for health risk reduction through drinking water regulation.”