On May 18, 2026, EPA proposed two significant changes to the federal drinking water regulations for PFAS (per- and polyfluoroalkyl substances), commonly known as “forever chemicals.” One would rescind the Biden-era standards for four categories of PFAS, and the other would extend the time for qualifying water systems to comply with existing standards for PFOA and PFOS by up to two additional years. Both proposals carry significant implications for regulated entities and environmental liabilities, yet both also face likely legal challenges—underscoring that the PFAS regulatory landscape continues to remain unsettled.
Background: The 2024 PFAS Drinking Water Rule
EPA finalized the PFAS National Primary Drinking Water Regulation in April 2024. The rule established legally enforceable maximum contaminant levels (MCLs) of 4.0 parts per trillion (ppt) for PFOA and PFOS, and 10 ppt for PFHxS, PFNA, and HFPO-DA. It also regulated certain mixtures of PFHxS, PFNA, HFPO-DA, and PFBS through
