EPA and Proposed MCL for Perchlorate

May 15, 2020, in the last couple of days there has been updated information released regarding EPA’s proposed MCL for perchlorate (see background discussion below).

New York Times and Washington Post

The New York Times and the Washington Post are reporting that EPA has decided not to regulate perchlorate in drinking water.  In both articles, EPA spokespeople indicate that a final decision has not yet been made.  The next step will be for EPA to submit the regulatory package to the Office of Management and Budget for review.

Washington Post


New York Times


EPA Press Release

Yesterday, EPA posted a Press Release with the heading “EPA Notes Successes in Reducing Perchlorate in Drinking Water.”  Link to EPA Press Release


With the Press Release, EPA also posted the enclosed two documents:

  1. Reductions of Perchlorate in Drinking Water (perchlorate_reductions_5.14.20)

2. Steps Water Systems Can Take to Address Perchlorate in Drinking Water (perchlorate_recommendations_for_pws_5.14.20 perchlorate_reductions_5.14.20)


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.”