On March 29, 2023, EPA published its proposed National Primary Drinking Water Regulations (NPDWR) to establish legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six per- and polyfluoroalkyl substances (PFAS), which include perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), hexafluoropropylene oxide dimer acid (HFPO-DA) and its ammonium salt (also known as a GenX chemical), perfluorononanoic acid (PFNA), and perfluorobutane sulfonic acid (PFBS).
For PFOA and PFOS, the agency proposed an individual MCL of 4 parts per trillion (ppt). For the remaining four, the agency proposed a unitless MCL of 1.0 based on an approach called a hazard index, which is used to evaluate potential health risks from exposure to chemical mixtures. EPA is also proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS. For PFOA and PFOS, the proposed MCLG is zero and for the other PFAS, the agency proposed the same unitless 1.0 hazard index.
The proposed rule would require public water systems to monitor for these PFAS, notify the public of the levels of these PFAS, and reduce the levels of these PFAS in drinking water if they exceed the proposed standards. This can include the installation of costly treatment technologies such as granular activated carbon (GAC), anion exchange (AIX), nanofiltration (NF) and reverse osmosis (RO) or switching to an alternative water source. The utilization of some of these technologies will also require public water systems to dispose treatment residuals that contain PFAS, which may result in additional costs if the agency designates any of the PFAS as a hazardous substance under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
EPA will be holding a virtual public hearing on May 4, 2023.
Comments are due on May 30, 2023.
Read the proposed rule and submit comments.
Advocacy contact: Tabby Zeb at 202-798-7405 or email at tayyaba.zeb@sba.gov.