EPA Announces Modifications To National Drinking Water Regulations

Key Takeaways

While EPA has proposed modifications to certain PFAS drinking water regulations, the PFOA and PFOS limits remain firmly in place, and EPA has signaled that a restarted rulemaking process could yield additional requirements for the rescinded compounds in the future.

On May 18, 2026, the U.S. Environmental Protection Agency (“EPA”) proposed two rules that would scale back previously announced drinking water regulations for per- and polyfluoroalkyl substances (“PFAS”). If implemented, these proposals would rescind Maximum Contaminant Levels (“MCLs”) for certain types of PFAS and would allow water systems to seek extensions of the April 2029 deadline for compliance with the National Primary Drinking Water Regulations (“NPDWR”). Notably, these proposals do not affect the MCLs of 4 parts per trillion for perfluorooctanoic acid (“PFOA”) and perfluorooctane sulfonic acid (“PFOS”).