Per- and Polyfluoroalkyl Substances (PFAS)

Information from the United States Environmental Protection Agency*

Final PFAS National Primary Drinking Water Regulation

On April 10, 2024, the EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS. To inform the final rule, EPA evaluated over 120,000 comments submitted by the public on the rule proposal, as well as considered input received during multiple consultations and stakeholder engagement activities held both prior to and following the proposed rule. EPA expects that over many years the final rule will prevent PFAS exposure in drinking water for approximately 100 million people, prevent thousands of deaths, and reduce tens of thousands of serious PFAS-attributable illnesses.

EPA is also making unprecedented funding available to help ensure that all people have clean and safe water. In addition to today’s final rule, $1 billion in newly available through the Bipartisan Infrastructure Law to help states and territories implement PFAS testing and treatment at public water systems and to help owners of private wells address PFAS contamination.

EPA finalized a National Primary Drinking Water Regulation (NPDWR) establishing legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS in drinking water. PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. EPA also finalized health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS.

The final rule requires:

  • Public water systems must monitor for these PFAS and have three years to complete initial monitoring (by 2027), followed by ongoing compliance monitoring. Water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027.
  • Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
  • Beginning in five years (2029), public water systems that have PFAS in drinking water which violates one or more of these MCLs must take action to reduce levels of these PFAS in their drinking water and must provide notification to the public of the violation.

Supporting Materials

General Information

Information for States, Tribes, and Water Systems

Regulatory Information


EPA is holding three informational webinars for communities, water systems, and other drinking water professionals about the final PFAS NPDWR. These webinars are scheduled on April 16, April 23, and April 30, 2024. The webinars will be similar, with each intended for specific audiences. Registration is required to attend and EPA requests that registrants only register for one of the webinars. The webinar recordings and presentation materials will be made available on this website following the webinars.  For questions related to the public webinars, please contact [email protected].


Under the Safe Drinking Water Act, EPA has the authority to set enforceable National Primary Drinking Water Regulations (NPDWRs) for drinking water contaminants and require monitoring of public water systems. In March 2021, EPA published Regulatory Determinations for Contaminants on the Fourth Contaminant Candidate List which included a final determination to regulate PFOA and PFOS in drinking water. As a part of that final determination, EPA indicated it would also evaluate additional PFAS and consider regulatory actions to address groups of PFAS.

On March 24, 2023, EPA proposed the PFAS NDPWR. Concurrent with the proposed rule, EPA also announced preliminary regulatory determinations for PFHxS, PFNA, HFPO-DA, and PFBS in accordance with the Safe Drinking Water Act regulatory development process. EPA proposed to regulate PFOA and PFOS with individual MCLs and PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index which accounts for co-occurring mixtures of these four PFAS. Concurrent with the final PFAS NPDWR announced on April 10, 2024, EPA also announced final individual regulatory determinations for PFHxS, PFNA, and HFPO-DA, and final regulatory determination for mixtures containing two or more of these three PFAS and PFBS. This regulation will also remove many other PFAS when they co-occur with these regulated PFAS.

Further Information

To learn more about PFAS and to find important background information to support understanding the details of specific actions EPA takes to address PFAS and other emerging events related to PFAS.

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