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June 5, 2026
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On May 20, 2026, the U.S. Environmental Protection Agency (EPA) published two proposed rules dealing with existing PFAS regulations under the Safe Drinking Water Act. Taken together, the first proposal would rescind 2024 regulations related to four forms of PFAS, and the second proposal would allow an extension of the compliance deadline for public water systems to achieve Maximum Contaminant Levels (MCLs) for PFOA and PFOS.
Proposed Rescission of Rules Related to Index PFAS
The first proposed rule would rescind all regulations in the 2024 National Primary Drinking Water Regulations (NPDWR) related to four groups of PFAS (collectively referred to as Index PFAS): PFHxS, PFNA, HFPO-DA (also known as GenX chemicals), and Hazard Index mixtures of these chemicals plus PFBS.
The EPA is proposing this rescission because the Agency believes that the regulations were promulgated under an unauthorized process. If enacted, the new rule would eliminate Maximum Contaminant Levels (MCLs) and Maximum Contaminant Level Goals (MCLGs) for these substances from the NPDWR. The proposed rule does not withdraw the risk findings related to these substances and the EPA may promulgate rules related to Index PFAS in the future.
Why it Matters: The compliance deadlines related to these Index PFAS have not yet been reached, so there is no immediate impact for states and tribal governments. However, any state, tribal, or local drinking water regulations that are directly tied to EPA standards would no longer have enforceable standards for these four substances.
On the other hand, non-federal regulations that adopted explicit numerical standards would likely remain in effect. Consequently, the proposed elimination of nationwide standards for Index PFAS may create regulatory inconsistency across different jurisdictions.
The proposed rule is available under Docket ID: EPA-HQ-OW-2025-0654.
The EPA is accepting written comments until July 20, 2026.
Proposed Extension of Compliance Deadline for PFOA and PFOS Standards
The second proposed rule would allow the EPA to extend the compliance deadline for the drinking water Maximum Contaminant Levels (MCLs) for PFOA and PFOS by up to two years for qualifying public water systems. Under the 2024 National Primary Drinking Water Regulations (NPDWR), the EPA established Maximum Contaminant Level Goals (MCLGs) of zero and MCLs of 4.0 parts per trillion (ppt) for both PFOA and PFOS, with compliance currently required by April 26, 2029.
Under the proposal, eligible public water systems could seek an extension of the MCL compliance deadline to as late as 2031. To qualify for an extension, a system would need to demonstrate that:
- Compelling factors prevent compliance by 2029;
- The extension would not pose an unreasonable risk to public health; and
- The system is actively working toward compliance.
The proposal does not alter monitoring, reporting, or public notification requirements.
Why it Matters: The proposed extension would apply only at the federal level and would not affect state or tribal requirements that impose different standards or timelines. While the proposal could give public water systems additional time to plan and prioritize compliance efforts, it does not reduce the need for businesses to continue taking proactive steps to address PFOA and PFOS in their waste streams.
The proposed rule is available under Docket ID: EPA-HQ-OW-2025-1742.
The EPA is accepting written comments until July 20, 2026.
Looking ahead, these proposals signal a potential shift in the federal approach to PFAS drinking water regulation, while leaving open the possibility of future rulemaking and continued state‑level activity. Stakeholders may wish to monitor how the EPA addresses comments on both proposals and consider how evolving federal standards could intersect with existing or emerging state requirements.
