What: On January 6, 2025, the U.S. Environmental Protection Agency (EPA) proposed a National Primary Drinking Water Regulation (NPDWR) and a health-based Maximum Contaminant Level Goal (MCLG) for perchlorate under the Safe Drinking Water Act (SDWA).
Why: Perchlorate is an inorganic chemical compound that occurs naturally and can also be manufactured. It is commonly used in solid rocket propellants, munitions, fireworks, airbag initiators for vehicles, matches, signal flares, and may also be found in fertilizers and as a byproduct of improper handling of hypochlorite solutions used for drinking water treatment. Perchlorate exposure to humans occurs primarily through the ingestion of contaminated food and drinking water.
In the proposed rule, the EPA is proposing to set the perchlorate MCLG at 0.02 mg/L (20 µg/L). The EPA is also proposing and taking comment on setting an enforceable Maximum Contaminant Level (MCL) for perchlorate at 0.02 mg/L (20 µg/L), 0.04 mg/L (40 µg/L), or 0.08 mg/L (80 µg/L).
Additionally, the EPA is proposing requirements for water systems to conduct monitoring for perchlorate in drinking water, take mitigation actions if the level exceeds the MCL, provide information about perchlorate to their consumers through public notification and consumer confidence reports, and report to their respective primacy agency.
The EPA has determined that the benefits of this proposal would not justify the costs. However, the agency is required to issue the proposed rule in response to a legal decision from the United States Court of Appeals for the District of Columbia Circuit.
Action: Comments on the proposed rule are due March 9, 2026. The EPA will hold a virtual public hearing on the proposed rule on February 19, 2026, from 1 PM to 4 PM ET.
PROPOSED RULE:
National Primary Drinking Water Regulation for Perchlorate
VIRTUAL PUBLIC HEARING REGISTRATION:
Public Hearing for the Proposed NPDWR for Perchlorate
OTHER INFORMATION:
EPA’s Perchlorate in Drinking Water page
CONTACT:
Nick Goldstein
EMAIL:
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