On May 20, 2026, EPA proposed rolling back the national primary drinking water regulations for PFHxS, PFNA, HFPO-DA (a group of PFAS known as GenX), and and any mixture containing two or more of PFHxS, PFNA, HFPO-DA, and perfluorobutane sulfonic acid (PFBS). The agency asserted the original regulations were promulgated unlawfully. EPA Administrator Zeldin stated the agency intends to “fix[] that error with standards water systems can actually implement and that will hold up to scrutiny.”
On the same day, EPA also proposed a rule that would extend compliance deadlines for the Maximum Contaminant Levels (MCLs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) from April 26, 2029, to April 26, 2031, for water systems that request an extension.
Comments for both proposals due July 20, 2026.
Background
PFAS, or “forever chemicals,” have been linked to cancer, impacts on the liver and heart, and immune and developmental harm to infants and children.
In April 2024, EPA issued the first legally enforceable drinking water standard to protect communities from PFAS exposure. The rule set Maximum Contaminant Levels (MCLs) for six PFAS in drinking water (PFOA, PFOS, PFHxS, PFNA, HFPO-DA, and certain mixtures) under the Clean Water Act. The rule also required water systems to monitor for these PFAS and disclose PFAS levels in drinking water to the public starting in 2027. EPA expected the rule to prevent PFAS exposure in drinking water for approximately 100 million people.
On the same day, EPA made nearly $1 billion available from the Bipartisan Infrastructure Law to support states and territories test and treat drinking water with PFAS in both public water systems and privately owned wells. Learn more about the PFAS Drinking Water Regulation Final Rule.