On April 10, 2024, the U.S. Environmental Protection Agency (EPA) announced the final National Primary Drinking Water Regulation (NPDWR) under the Safe Drinking Water Act. The NPDWR established legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six per- and polyfluoroalkyl substances (PFAS) in drinking water.
Specific PFAS Regulations and Levels
Five of the PFAS, specifically perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), and hexafluoropropylene oxide dimer acid (HFPO-DA) are contaminants with individual MCLs. PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and perfluorobutane sulfonate (PFBS) use a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water.
Enforceable Limits and Goals for PFAS in Drinking Water
EPA finalized an enforceable four parts per trillion (ppt) limit on PFOA and PFOS in drinking water. The agency also set a non-enforceable maximum contaminant level goal for PFOA and PFOS at zero, reflecting research showing that no level of exposure is risk-free. The rule further set a limit of 10 ppt on three other categories of PFAS in drinking water, including PFNA, PFHxS, and “GenX” chemicals. GenX chemicals are made to produce fluoropolymers used in semiconductor chips.
Public Water Utility Systems Requirements
The EPA estimates that of the 66,000 public water utility systems impacted by the standard, 6% to 10% may need to act to comply with the regulations. Operators will have three years to test for PFAS pollution and then an additional two years to identify, purchase, and install the necessary technology to treat contaminated water.
There will be three informational webinars hosted by EPA for communities, water systems, and other drinking water professionals about the final PFAS NPDWR, scheduled for April 16, April 23, and April 30, 2024, respectively.
Challenges and Costs of Compliance
Manufacturers, business groups, and potentially water systems themselves are likely to argue that EPA’s rules were crafted without adequately considering the cost of compliance or without adequate evidence showing the need for the rules, in violation of requirements under the Safe Drinking Water Act and federal administrative law.
EPA estimates that it will cost water companies $1.5 billion a year to comply with the new regulation. These costs include ongoing monitoring and maintenance of equipment, such as replacing carbon filters on a regular schedule.
EPA is making $1 billion available to states and territories to implement PFAS testing and treatment at public water systems. That money is part of a $9 billion investment made possible by the 2021 Bipartisan Infrastructure Law to fund efforts to mitigate PFAS in water systems.
Broader Impact on Environmental Remediation Efforts
These new MCLs are likely to be adopted into remedial actions performed pursuant to the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERLCA), especially in light of the fact that EPA intends to finalize its proposed rule to list PFOA and PFOS as hazardous substances under CERCLA.
