On May 20, 2026, EPA proposed to rescind several components of its 2024 rule that limited the amount of per- and polyfluoroalkyl substances (PFAS) in public drinking water systems.
EPA issued Safe Drinking Water Act (SDWA) regulations in 2024 for six PFAS: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA), and perfluorobutane sulfonic acid (PFBS). In that rulemaking, EPA found that exposure to these PFAS could cause adverse health effects, including liver damage, low birth weights, and increased risks of certain cancers and projected that, if fully implemented, its 2024 rule would result in “29,858 fewer illnesses and 9,614 fewer deaths” over the following decades.
EPA now proposes to rescind both its determinations to regulate and its drinking water standards for four of the six PFAS regulated by the 2024 rule: PFHxS, PFNA, HFPO-DA, and PFBS. Based on a revised interpretation of SDWA section 1412(b)(1)(E), EPA asserts that the 2024 rulemaking used an unlawful procedure to regulate these PFAS.
This quick take compares EPA’s 2024 and 2026 interpretations of SDWA section 1412(b)(1)(E), describes potential legal and practical implications of EPA’s proposal, and highlights legal risks EPA may face if it finalizes the proposal.