EPA Proposes to Rescind Certain PFAS Drinking Water Standards and Extend Compliance Deadlines for PFOA and PFOS
The Environmental Protection Agency ("EPA") published two proposed rules that would rescind drinking water standards for four per- and polyfluoroalkyl substances ("PFAS") while extending compliance deadlines for two others.
On May 20, 2026, EPA published two proposed rules addressing PFAS under the Safe Drinking Water Act ("SDWA"). Together, these proposals would scale back the scope and implementation timeline of the agency's 2024 PFAS National Primary Drinking Water Regulation ("NPDWR").
In the first proposed rule, EPA proposes to remove the Maximum Contaminant Levels ("MCLs") and related regulatory provisions for four PFAS: perfluorohexane sulfonic acid ("PFHxS"), perfluorononanoic acid ("PFNA"), hexafluoropropylene oxide dimer acid ("HFPO-DA," commonly known as GenX chemicals), and the hazard index mixture that includes these three PFAS and perfluorobutane sulfonic acid ("PFBS"). EPA determined that, in 2024, it failed to follow the proper procedural requirements as set forth in the SDWA because EPA simultaneously proposed and finalized the regulatory determinations and drinking water standards, rather than proceeding sequentially. The proposed rule is intended to address the procedural concerns first raised by the EPA in May 2025. Despite its acknowledgement, this proposed rule is the first formal step to reducing the regulation of these four PFAS under the SDWA.
EPA's second proposed rule provides an exemption framework under SDWA 1416(f) and 1450(a)(1). This would extend the compliance deadlines for the perfluorooctanoic acid ("PFOA") and perfluorooctane sulfonic acid ("PFOS") MCLs by two years—from April 26, 2029, to April 26, 2031—for qualifying public water systems who submit and are granted an exemption request. However, public water systems with PFOA or PFOS levels at or above 12 parts per trillion that request a compliance extension would be required to implement interim control measures during the two-year period.
Together, the proposals represent a significant rollback of the Biden administration's 2024 PFAS drinking water regulations. Comments on both proposed rules are due by July 20, 2026. The EPA will also hold a virtual public hearing on July 7, 2026. As EPA moves forward with these proposed rules, challenges to the 2024 MCLs are ongoing in the D.C. Circuit.
