AMWA Delivers Verbal Comments In Public EPA Perchlorate NPDWR Session

Last week, AMWA delivered verbal comments during the Agency’s public listening session on the proposed National Primary Drinking Water Regulation (NPDWR) for perchlorate. The Association’s comments iterated the Agency’s points that EPA’s data show that for the vast majority of water systems nationwide occurrence of perchlorate in surface and ground water falls below any of the Agency’s proposed enforcement levels. The Association also expressed support for the Agency’s proposed monitoring provisions that would reduce burdens while maintaining public health protection.

As part of the proposal, the Agency proposed a maximum contaminant level goal (MCLG) of 20 μg/L and co-proposed three options for an enforceable maximum contaminant level (MCL): 20, 40, and 80 μg/L. The draft NPDWR also includes an initial compliance testing and monitoring schedule that would allow systems with initial compliance monitoring samples or historical samples dating back to January 1, 2021, of below 4 μg/L to qualify for a reduced monitoring schedule, incorporating monitoring flexibilities that EPA requested in its federalism consultation comments. The remainder of the compliance monitoring follows EPA’s Standardized Monitoring Framework (SMF) for inorganic contaminants (IOCs). The proposal also contains treatment options, public notice, and consumer confidence report requirements.

AMWA worked with the regulatory subcommittee to develop verbal comments and is actively working to develop written comments on the draft proposal. The subcommittee will discuss draft written comments in the March 2 regulatory subcommittee meeting. AMWA members who are not on the subcommittee but are interested in participating in the meeting or reviewing AMWA’s comments on the draft perchlorate NPDWR should contact Jessica Evans, AMWA’s Director of Regulatory Affairs. Comments are due March 9.

The Agency’s action follows years of back-and-forth on whether and how to regulate the contaminant. In 2011, EPA first determined that it would regulate perchlorate in drinking water under SDWA; however, the Agency delayed establishing a maximum contaminant level (MCL), in order to complete further scientific peer review that the EPA Scientific Advisory Board recommended. EPA then proposed a NPDWR in 2019 that included an MCL and maximum contaminant level goal of 56 μg/L and sought comment on alternative levels of 18 μg/L and 90 μg/L, as well as an option to withdraw the regulatory determination entirely. In 2020, EPA withdrew the 2011 regulatory determination. The D.C. Circuit vacated that withdrawal in 2023, reinstating EPA’s obligation to regulate perchlorate and setting deadlines for a proposed rule by November 21, 2025, and a final rule by May 2027.