EPA Announces Final Drinking Water Limits for PFAS Compounds

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On April 10, 2024, the U.S. Environmental Protection Agency released the final National Primary Drinking Water Regulation for six PFAS compounds. The final rule follows issuance of a proposed rule on March 14, 2023, which was previously discussed here. The limits in the final rule altered the proposed rule by setting a specific MCL for PFHxS, PFNA, and GenX, which had previously only been proposed for regulation through a hazard index approach. The limits under the final rule are:

The final rule imposes traditionally enforceable limits of 4 parts per trillion for two compounds (PFOA and PFOS) along with an unenforceable health-based Maximum Contaminant Level Goal (“MCLG”) of zero for those two compounds. The MCL and MCLG for PFHxS, PFNA, and GenX are set at a uniform 10 parts per trillion. An enforceable “hazard index” limit for those three compounds, along with PFBS, is also included in the final rule, which will require drinking water systems to compare (via an EPA web-based form) the amount of all of the specified PFAS chemicals present in its drinking water to associated health-based levels to determine whether any human health effects are expected.

The public comment period for the proposed rule ended on May 30, 2023, and over 120,000 public comments were received by the agency. While many individual citizens and non-governmental organizations commented favorably on the proposed rule, citing its purported health protection benefits, many utilities and regulatory associations voiced concerns about the proposed rule. The concerns raised include:

• The potential costs of capital improvements and treatment to comply with the rule (many believe EPA’s estimates are significantly low);
• The cost and availability of appropriate disposal methods for PFAS-contaminated wastes;
• The capacity of available analytical laboratories;
• The use of a hazard index to regulate collectively a number of compounds which do not (in all cases) have the same health concerns;
• The risk communication aspects of a disparate MCL and lower “goal” number for PFOS and PFOA.

The final rule gives public water systems three years (2027) to complete initial monitoring for the listed compounds followed by continued compliance monitoring. The systems have five years (2029) to implement treatment if monitoring shows regulated PFAS compounds at levels above the MCLs or hazard index limits. While EPA fact sheets points to billions of dollars in federal infrastructure dollars available to address the costs of compliance with the new rule, many utility-based stakeholders have expressed doubt that the available funding will be sufficient to address the needed improvements at drinking water facilities nationwide. If these concerns prove out, the consequences of the final rule will include potentially severe increases in drinking water rates for consumers in many jurisdictions.

It is unclear at this point what legal challenges may be forthcoming to challenge the new rule, but recent history would indicate that some degree of litigation over implementation is likely.