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.”
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About Dan Askenaizer

Dr. Askenaizer leads WQTS’ work on regulatory compliance support for many of our water agencies clients. Dr. Askenaizer tracks water quality and treatment regulations at the Federal and State levels and provides regulatory updates to our clients. Dr. Askenaizer has strong expertise in the development of Regulatory Monitoring and Compliance Plans (RMCPs), which he has completed for a number of water agencies. He has also been working on a number of projects dealing with the development of distribution system monitoring plans and review of nitrification control strategies. Prior to joining WQTS, Dr. Askenaizer was the Water Quality Manager for the Glendale Water and Power. Under his leadership, the Water Quality Group conducted a demonstration-scale study of chlorite for nitrification control and a pilot-scale study of biological treatment for removal of nitrate. Dan has 30 years of experience working on projects dealing with regulatory, water quality and public health issues. Dan has given numerous presentations at workshops and round-tables across the country for water utilities. Dan was instrumental in developing and implementing a Mentoring Program for water staff and was involved in a Sustainable Development team.