On April 10, the U.S. Environmental Protection Agency (EPA) adopted the final National Primary Drinking Water Regulations (Rule) for six per- and polyfluoroalkyl substances (PFAS): perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), and perfluorobutane sulfonic acid (PFBS).
The Rule establishes both legally enforceable Maximum Contaminant Levels (MCLs) and health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS in drinking water. This Rule also effectively establishes groundwater clean-up standards in some states including Michigan, Pennsylvania, and Wisconsin, and, for two of the identified PFAS (PFOA and PFOS) the Rule establishes the remedial action cleanup criteria for hazardous substances in groundwater under the Federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
Under the Rule, certain community water systems (meaning “a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents”) and non-transient non-community water systems (i.e., “a public water system that is not a community water system and that regularly serves at least 25 of the same persons over six months per year”) must monitor for the presence of these PFAS. Such systems have three years to complete initial monitoring (i.e., by 2027), followed by ongoing compliance monitoring.
Covered water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027. If the required monitoring shows that PFAS concentrations exceed the new MCLs, public water systems have five years (i.e., by 2029) to implement solutions to achieve compliance with these MCLs. Beginning in 2029, public water systems that have PFAS levels exceeding the MCLs will be considered in violation of the Rule and will be required to take action to reduce PFAS levels in their drinking water and also to provide notification to the public of the violation.
