EPA Issues New Guidance on Limiting Exposure to PFAS in Drinking Water

June 16, 2022

Key Takeaways

  • EPA has issued new and much lower guidance values for four PFAS chemicals.
  • EPA recognizes that it has set levels for PFOA and PFOS that are below a reliable level of detection.
  • Other PFAS guidance values and potential regulations may be forthcoming.
  • Stakeholders should be prepared for the potential mandatory regulations.

The U.S. Environmental Protection Agency (EPA) announced new interim lifetime drinking water health advisories for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), as well as final health advisories for two other perfluoroalkyl substances (PFAS).1 PFAS have historically been used by a wide range of industries for their water-resistant and stain-resistant properties, as well as their stability.2 PFOA and PFOS are among the more well-known PFAS compounds.

EPA Provisionally Recommends PFOA and PFOS Exposure Below Detectable Thresholds

In its new, interim advisories, the EPA recommends that lifetime exposure to PFOA and PFOS in drinking water be no more than 0.004 parts per trillion (ppt) and 0.02 ppt, respectively.3 This is a marked reduction to the EPA’s 2016 guidance value of 70 ppt, separately or in combination, for these chemicals4 —more than 17,000 times lower for PFOA. The EPA also acknowledges that these values are below “the level of both detection (determining whether or not a substance is present) and quantitation (the ability to reliably determine how much of a substance is present). This means that it is possible for PFOA or PFOS to be present in drinking water at levels that exceed health advisories even if testing indicates no level of these chemicals.”5 The interim level for PFOS is 200 times lower than can be measured by current technology; it is 1,000 times below measurement limits for PFOA.6

According to the EPA, these levels were “calculated to offer a margin of protection” for public health and were based on studies of children’s immune responses to vaccination for diphtheria and tetanus.7 While the EPA provisionally interpreted the studies to “indicate[] an association between increased serum levels of PFOA and decreased antibody production,”8  it noted that “these studies did not measure infection or illness rates, only response to vaccines.”9 The EPA has not made a scientific determination that PFOA or PFOS causes any adverse health condition in humans.

EPA Establishes Guidance for Two Additional Substances

In addition to its interim, updated guidance for PFOA and PFOS, the EPA also issued final lifetime health advisories for perfluorobutane sulfonic acid and its potassium salt (PFBS) and hexafluoropropylene oxide (HFPO) dimer acid and its ammonium salt.10 The EPA now recommends that exposure to PFBS and HFPO in drinking water be limited to 2,000 ppt and 10 ppt, respectively.11 These values were based on animal studies reporting liver changes for HFPO and thyroid function for PFBS.12

The Import of the EPA’s Guidance

Although health advisories (both interim and final) are non-enforceable and non-regulatory guidance,13 they may foreshadow mandatory, regulatory action or litigation trends in the near term. Stakeholders should take heed and prepare for future developments.

  • The EPA is developing a National Drinking Water Regulation for PFOA and PFOS under the Safe Drinking Water Act, which it expects to propose later this year and promulgate in 2023.14 EPA Administrator Michael S. Regan has indicated that his agency will “take aggressive action as part of a whole-of-government approach to prevent these chemicals from entering the environment.”15 These advisories—and any subsequent regulation—are just one prong of the Biden administration’s PFAS Strategic Roadmap, which includes efforts related to monitoring public drinking water systems, Clean Water Act permitting, and CERCLA removal actions.16 The EPA is already considering regulatory action to address groups of PFAS.17
  • The EPA’s advisories, likewise, provide “technical information” and “guidance” to drinking water system operators, as well as federal, state, Tribal, and local officials,18 which can influence regulatory determinations and actions by other agencies and levels of government. This non-regulatory guidance also has the potential to affect decision-making about equipment for removing PFAS in drinking water.
  • In addition, the plaintiffs’ bar can be expected to pay attention to the EPA’s announcement and incorporate the agency’s guidance into its litigation strategies.

Read more about our coverage of PFAS and litigation trends here.


  1. EPA, Drinking Water Health Advisories for PFAS Fact Sheet for Communities (June 2022), (“EPA, Fact Sheet”).
  2. Gluge et al., An Overview of the uses of per- and polyfluoroalkyl substances (PFAS) (2020). Environ. Sci.: Processes, 22:2345, 2349.
  3. EPA, Interim Drinking Water Health Advisory: Perfluorooctanoic Acid (PFOA) (June 2022); EPA, Interim Drinking Water Health Advisory: Perfluorooctane Sulfonic Acid (PFOS) (June 2022).
  4. EPA, Fact Sheet: PFOA & PFOS Drinking Water Health Advisories (November 2016).
  5. EPA, Questions and Answers: Drinking Water Health Advisories for PFOA, PFOS, GenX Chemicals and PFBS,  (“EPA, Q&A”).
  6. EPA, Q&A, supra.
  7. Id.
  8. EPA, External Peer Review Draft, Proposed Approaches to the Derivation of a Draft Maximum Contaminant Level Goal for Perfluorooctanoic Acid (PFOA) (CASRN 335-67-1) in Drinking Water (November 2021).
  9. EPA, Q&A, supra.
  10. EPA, “EPA Announces New Drinking Water Health Advisories for PFAS Chemicals, $1 Billion in Bipartisan Infrastructure Law Funding to Strengthen Health Protections” (June 15, 2022), (“EPA, Press Release”).
  11. EPA, Drinking Water Health Advisory: Perfluorobutane Sulfonic Acid (CASRN 375-73-5) and Related Compound Potassium Perfluorobutane Sulfonate (CASRN 29420-49-3) (June 2022); EPA, Drinking Water Health Advisory: Hexafluoropropylene Oxide (HFPO) Dimer Acid (CASRN 13252-13-6) and HFPO Dimer Acid Ammonium Salt (CASRN 62037-80-3), Also Known as “GenX Chemicals”.
  12. EPA, Q&A, supra.
  13. EPA, Fact Sheet, supra.
  14. EPA, Q&A, supra.
  15. EPA, Press Release, supra.
  16. Id.
  17. EPA, Q&A, supra.
  18. Id.

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