EPA Proposes Amendments to PFAS Drinking Water Rule

This week, EPA released two proposed rules amending the National Primary Drinking Water Regulations (“NPDWR”) for PFAS, which were finalized in April 2024.[1] The first proposal would authorize water systems to request two additional years to comply with the Maximum Contaminant Levels (“MCLs”) for PFOA and PFOS in drinking water,[2] and the second proposal would rescind the MCLs for four other PFAS: PFHxS, PFNA, HFPO-DA, and the conglomerate Hazard Index of those three chemicals combined with PFBS.[3]

To receive an extension under the first rule, systems will be required to submit recent PFAS sampling results, certify that they cannot comply with the MCLs by April 2029, and provide other information detailed further below. And systems with PFOA or PFOS testing results at or greater than 12 parts per trillion (“ppt”), will be required to commit to at least two forms of prescribed control measures. Those measures include steps to protect and provide notice to water system customers.

These updates were previewed by EPA a year ago, when EPA announced its intention to retain the PFOA and PFOS MCLs.[4] Once finalized, EPA’s move to provide compliance extensions and rescind the MCLs for PFAS other than PFOA and PFOS will almost certainly be challenged in court.[5] Suits seeking to stop the rollback will likely invoke the Safe Drinking Water Act’s “anti-backsliding” provision that requires any change to national drinking water regulations to “maintain, or provide for greater, protection of the health of persons,”[6] and suits challenging the extension may challenge the legality of using the exemption provision under SDWA § 1416 to create a nationwide rule instead of a rule requiring case-by-case determinations.[7] These suits would be in addition to ongoing litigation initiated by industry in 2024 challenging the PFAS MCLs, including the PFOS and PFOA MCLs, as improperly promulgated and imposing excessive costs. Together, the shifting rule and parallel litigations are creating an unpredictable regulatory environment for water providers just as they are making crucial funding and expenditure decisions needed to comply with the PFAS MCLs.

Impacted parties seeking to influence the final rules may submit comments to EPA for 60 days after the proposed rules are published in the Federal Register. A virtual public hearing on both proposed rules will also be held on July 7, 2026.

Compliance Extension Proposal

The first proposed rule allows systems to apply for two additional years to meet the MCLs for PFOA and PFOS, moving the compliance deadline from April 26, 2029 to April 26, 2031. The MCLs will otherwise remain at the current 4 ppt standard set in the April 2024 PFAS NPDWR.[8]

To receive the extension, systems will be required to provide all requested information, which will include the following substantive submissions along with additional administrative filings:

• The system’s most recent PFOA and PFOS drinking water sample results;
• A certified statement that the system cannot comply with the 2024 PFAS NDPWR by the April 2029 deadline and that management or restructuring changes (or both) cannot reasonably be made that will result in compliance or improve the quality of the drinking water;
• A certified statement that the system is taking all practicable steps to meet the standard; and either:
  • The system cannot meet the standard without capital improvements, which cannot be completed prior to April 2029;
  • In the case of a system which needs financial assistance for the improvements, the system has entered into an agreement to obtain such financial assistance, or assistance is reasonably likely to be available within the exemption period; or,
  • The system has entered into an enforceable agreement to become part of a regional public water system.

To be eligible, systems must also be in operation on or prior to June 25, 2024 – the effective date of the PFOA and PFOS MCLs – and must not be a small system that has received a SDWA § 1415(e) variance because it cannot afford to comply with the PFOA and PFOS MCLs. [9]

For systems with a PFOA or PFOS sample result at or above 12 ppt, the systems must implement at least two of the following control measures during the exemption period; only one of the two required control measures may be a public education measure. In their exemption request, these systems must also certify which two control measures they plan to implement:

• Providing water pitchers and filters certified by an American National Standards Institute (“ANSI”)-accredited organization to reduce PFOA and PFOS levels;
• Delivering alternative water supplies with lower levels of PFOA and PFOS;
• Installing, operating, and maintaining point-of-use or point-of-entry devices certified by the National Science Foundation/ANSI to decrease PFOA and PFOS levels;
• Implementing actions and plans to decrease PFOA and PFOS levels in drinking water sources;
• Public education: Distributing written public education materials to consumers on PFOA and PFOS exposure sources; and
• Public education: Conducting community educations outreach activities on PFOA and PFOS in drinking water.

All systems granted an extension, including those without a PFOA or PFOS sample result at or above 12 ppt, would still be required to monitor and report their PFOA and PFOS levels according to the requirements and timeframes in the 2024 PFAS NDPWR, including the annual public notification and Consumer Confidence Report (“CCRs”) requirements. Public notices and CCRs must also inform the public regarding any exemptions, including the reason for the exemption and the status of the system’s response to its PFAS contamination. Systems implementing control measures must provide status updates on those initiatives as well.

Requests for exemptions must be made within 180 days of the finalization of the rule. EPA proposes that water systems that provide the requested information for an extension will be granted one, and that exemptions will only be terminated if EPA finds the system has failed to comply with the exemption requirements. The Economic Analysis for the proposal estimates that 100% of public water systems with PFOA and PFOS levels above the MCLs will receive the proposed extensions, further underscoring that the EPA plans to approve all complete individual system submissions.

An important qualification is that EPA-provided exemptions will only be available for systems located in a state, territory, or Tribe that does not have primacy for the 2024 PFAS NPDWR. EPA delegates primary enforcement responsibility, referred to as primacy, to states and Indian tribes that have enacted regulations for contaminants that are no less stringent than the standards promulgated by EPA.[10] While some states have begun pursuing primacy for the 2024 PFAS NPDWR, EPA has extended the deadline for states to apply until April 2028. If a state ultimately promulgates its own PFOA and PFOS regulations and receives primacy, the state can also decide whether to extend equivalent compliance extension opportunities to its water systems. States may also choose to provide systems with an extension for a third year to achieve compliance,[11] and smaller water systems (those serving a population less than 3,300) are eligible to apply for six total years of exemptions.[12] Water systems will want to carefully track state-specific rules to confirm what if any compliance deadline extensions will be available in their states.

EPA states that for systems struggling to navigate their PFAS contamination response plans, especially those in rural and small communities, it is offering enhanced outreach and support through the PFAS OUT and EPA’s RealWaterTA initiatives. Although these programs do not provide additional funding opportunities, they may be a resource and source of technical support for water systems responding to the PFAS regulatory environment. 

Finally, while not formally part of the proposed rulemakings, EPA did reaffirm its commitment to developing effluent limitation guidelines (“ELGs”) that would stop PFAS from entering drinking water systems. If promulgated, ELGs targeting PFOA and PFOS would be intended to reduce contamination levels experienced by many water systems, which EPA identified as another factor supporting an extension of water systems’ MCL compliance deadlines.

MCL Recission Proposal and Ongoing Litigation

The second proposed rule will rescind the MCLs for four additional PFAS: PFHxS, PFNA, HFPO-DA, and the conglomerate Hazard Index of those three chemicals combined with PFBS. The impact of these recissions will vary based on water system. For many systems, these chemicals are found co-located with PFOA and PFOS, and remedial approaches to address PFOA and PFOS will lower the contamination levels of these additional PFAS as well.

EPA has argued that the repeal of these MCLs is necessary because they were promulgated without following statutorily prescribed procedures by proposing MCLs for PFHxS, PFNA, HFPO-DA, and PFBS (individually or in combination) at the same time as issuing preliminary regulatory determinations for those chemicals.[13] Water industry associations and manufacturers have raised the same arguments in an ongoing legal challenge to all six of the PFAS MCLs, a lawsuit initiated in 2024 whose resolution, depending on when that occurs, might alter the finalization of both proposed rules.[14]

Last fall, EPA moved for partial vacatur of the PFAS rule in that litigation, leaving in place only the MCLs for PFOS and PFOA.[15] It also moved to sever and hold in abeyance the litigation insofar as the industry challengers’ petition targeted the other four PFAS subject to the proposed partial rescission.[16] The D.C. Circuit denied both motions, finding that “summary action” like partial vacatur would be inappropriate because the merits of the parties’ arguments were not clear.[17]

The challengers to the PFAS MCLs had also argued that EPA underestimated the regulation’s costs, an argument that still applies to the remaining MCLs for PFOS and PFOA even if the EPA’s proposed rule rescinding the MCLs for the other PFAS is finalized. Accordingly, the D.C. Circuit’s decision on this argument will still impact whether the MCLs need to be revised again as to PFOS and PFOA—leading to an unclear regulatory picture just as water providers are making decisions on funding and capital expenditures needed to comply with the PFAS MCLs.

Conclusion

If finalized, these rules will potentially provide regulatory relief to drinking water systems responding to PFAS contamination. But drinking water systems will still need to evaluate state-law developments to determine their eligibility for the Compliance Extension Rule and remain alert to whether legal challenges to either rule impact implementation.

To obtain more information on the proposed rules, submit a comment, or discuss the PFAS regulations more generally, please contact Jeff Kray, Jessica Ferrell, or Isabel Carey for more information.

[1] EPA, Per- and Polyfluoroalkyl Substances (PFAS): Final PFAS National Primary Drinking Water Regulation (last updated on May 18, 2026), https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas.

[2] EPA, Proposed PFOA and PFOS Compliance Extension Rule (last updated on May 20, 2026), https://www.epa.gov/sdwa/proposed-pfoa-and-pfos-compliance-extension-rule.

[3] EPA, Proposed PFAS Rescission Rule (last updated on May 20, 2026), https://www.epa.gov/sdwa/proposed-pfas-rescission-rule.

[4] EPA, EPA Announces It Will Keep Maximum Contaminant Levels for PFOA, PFOS (May 14, 2025), https://www.epa.gov/newsreleases/epa-announces-it-will-keep-maximum-contaminant-levels-pfoa-pfos.

[5] Several organizations have already signaled opposition to the rule. See, e.g., Press Release, EPA Seeks to Gut PFAS Protections, Leaving Millions Exposed to Toxic Forever Chemicals in Tap Water, NRDC (May 18, 2026), https://www.nrdc.org/press-releases/epa-seeks-gut-pfas-protections-leaving-millions-exposed-toxic-forever-chemicals-tap; Press Release, EPA proposes to gut limits on toxic PFAS in drinking water, abandoning communities across the country, Southern Environmental Law Center (May 18, 2026), https://www.selc.org/press-release/epa-proposes-to-gut-limits-on-toxic-pfas-in-drinking-water-abandoning-communities-across-the-country/.

[6] See 42 U.S.C. § 300g-1(b)(9).

[7] See 42 U.S.C. § 300g-5.

[8] EPA, Per- and Polyfluoroalkyl Substances (PFAS): Final PFAS National Primary Drinking Water Regulation, https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas.

[9] For more information on small system variances under the SDWA: EPA, Variances and Exemptions (last updated on Jan. 2, 2026), https://www.epa.gov/dwreginfo/variances-and-exemptions.

[10] For more information on state and tribal primacy for drinking water standards: EPA, Primary Enforcement Responsibility for Public Water Systems (last updated on Oct. 23, 2025), https://www.epa.gov/dwreginfo/primacy-enforcement-responsibility-public-water-systems.

[11] 42 U.S.C. § 300g-5(b)(2)(A).

[12] 42 U.S.C. § 300g-5(b)(2)(C).

[13] Motion to Vacate, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. Sep. 11, 2025).

[14] Petition for Review, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. June 7, 2024), https://www.amwa.net/system/files/linked-files/AWWA-v-EPA-No-1188-DC-Cir-Filed-Petition_0.pdf.

[15] Motion to Vacate, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. Sep. 11, 2025).

[16] Motion to Sever, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. Feb. 19, 2026).

[17] Order, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. Jan. 21, 2026); Order, American Water Works Association v. EPA, No. 24-1188 (D.C. Cir. Mar. 19, 2026).