On March 14, the United States Environmental Protection Agency (EPA) proposed the first federally enforceable drinking water limits for members of the widely used family of compounds commonly known as PFAS. EPA is proposing drinking water maximum contaminant levels (MCLs) for six per- and polyfluoroalkyl substances (PFAS). The levels for two common constituents, PFOA and PFOS, would be set at four parts per trillion (4 ppt), which is the level EPA says laboratories can reliably measure. Other constituent levels would be based on a Hazard Index, using combined levels of the constituents and a mathematical formula.
EPA’s proposal has been expected for some time and follows EPA’s 2021 PFAS Strategic Roadmap. The proposal will be a National Primary Drinking Water Regulation under the Safe Drinking Water Act. It will be published in the Federal Register and will be subject to public comments. EPA has said it wants to finalize the regulation by the end of 2023. When finalized, the requirements will apply to drinking water systems nationwide.
EPA has published a website for information about the proposed PFAS drinking water regulation, which contains background and technical links, along with information about public webinars on March 16 and March 28, a public hearing on May 4, and the regulatory docket for written comments. EPA says registration is required to participate in the webinars and public meeting.
If finalized in its current form, the regulation would have several other impacts. Beginning three years after the rule is finalized, water systems would begin monitoring for PFAS. Public notifications would be required within 30 days after a water system learns of a violation. Facilities that treat water to remove PFAS and other constituents will need to comply with appropriate waste handling and disposal requirements. Technical experts say the current methods for PFAS removal and disposal are inefficient and costly.
The proposal would set maximum contaminant level goals (MCLGs) at zero for certain PFAS compounds. Although not enforceable, such figures can come into play in public discussions about potential constituent exposures.
Other environmental media programs will be affected, as well. For example, MCLs often are used as screening tools for waste management and for remediation sites. Proposals have been advanced under other programs to regulate PFAS in wastes, wastewaters, and contaminated media.
EPA’s proposed PFAS regulation is likely the first of a series of legally enforceable standards affecting these widely used compounds. Stakeholders will want to participate in EPA’s public sessions and public comment process in order to be sure their perspectives are considered.