July 1, 2026

PFAS Proposals Would Delay and Rescind Drinking Water Standards

Extending Compliance Deadlines for PFOA and PFOS MCLs

On May 20, 2026, EPA proposed to allow requests for a two-year delay of the compliance deadlines for two per- and polyfluoroalkyl substances (PFAS) for which national primary drinking water regulation (NPDWR) standards were established in 2024. [91 FR 10086] The extension would apply to only two PFAS chemicals, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). If the rule is finalized, public water systems (PWSs) would need to request use of the compliance exemption within 180 days of the date the final rule is published. [40 CFR §142.58(b)] PWSs would also have to provide information on water sample results and a certified statement explaining why the system can’t comply with the original deadline of April 26, 2029. If granted the extension, the PWS would have until April 26, 2031 to comply with maximum contaminant levels (MCLs). PWSs granted the exemption would have to notify customers of the exemption and implement control measures if PFOA or PFOS levels are above 12 ppt during the exemption period. [40 CFR §142.59]

The exemption would only be available to PWSs that are regulated by the 2024 PFAS NPDWR, in operation on or before June 25, 2024, not operating under a small system variance (SDWA Section 1415(e) [42 U.S.C. Section 300g-4(e)]), and in a state that does not have primacy for the 2024 PFAS NPDWR. [40 CFR §142.58(a)] EPA says the extra time is intended to help water systems address implementation challenges associated with meeting the PFAS standards, especially for installing treatment technology and securing financing. The underlying 2024 MCLs and maximum contaminant level goals (MCLGs) of 4 ng/L (ppt) and 0 ng/L, respectively, for PFOA and PFOS are not being rescinded. Comments on the proposal may be submitted through July 20, 2026 via Docket ID No. EPA-HQ-OW-2025-1742.

Rescission of Regulatory Determinations and MCLs/MCLGs for Four PFAS Chemicals

In another proposal from May 20, 2026, EPA aims to rescind regulations for four additional PFAS chemicals:

Perfluorohexane sulfonic acid (PFHxS);
Perfluorononanoic acid (PFNA);
Hexafluoropropylene oxide dimer acid and its ammonium salt (HFPO-DA, called GenX chemicals); and
Perfluorobutane sulfonic acid (PFBS). [91 FR 29413]

The rule would remove the MCLs and MCLGs, the hazard index determination, monitoring requirements, and other compliance provisions for these chemicals impacting PWSs. EPA justifies the proposal through a procedural and legal explanation—the SDWA does not allow the agency to decide that a contaminant should be regulated and to issue the proposed drinking water regulation for that contaminant simultaneously. Rather, the SDWA requires a sequential process: a preliminary determination, public comment, a final determination to regulate, and a separate proposal followed by a final rule. These steps were followed for PFOA and PFOS, but not for the other four listed PFAS chemicals.

Adherence to the rule of law is always commended, and the agency is undoubtedly aware of the SDWA’s anti-backsliding provision (SDWA Section 1412(b)(9) [42 U.S.C. Section 300g-1(b)(9)], a prohibition on the weakening of drinking water standards once already established. Comments on the proposal may be submitted through July 20, 2026 via Docket ID No. PEA-HQ-OW-2025-0654.

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