Namely, EPA intends to extend PFOA and PFOS compliance deadlines, create a federal exemption framework, initiate more outreach to water systems, particularly in rural and small communities, and rescind or reconsider the regulatory determinations for perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA), and perfluorobutane sulfonic acid (PFBS), along with the controversial Hazard Index.  

These substances are part of a group of chemicals called per- and polyfluoroalkyl substances (PFAS). Known colloquially as “forever chemicals,” they are widely used for commercial and industrial purposes. Environmental releases of PFAS have led to its presence in air, soil, food, and water. This has become a concern due to PFAS’ potential adverse impacts on human health and the environment. Under the Safe Drinking Water Act (SDWA), Maximum Contaminant Levels (MCLs) for these six substances were published in the Federal Register in April 2024 and went into effect in June 2024.  

 Table: EPA PFAS Drinking Water Limits Evolution 2009-2024

Tell Me More About NPDWR 

NPDWR include legally enforceable MCLs and non-enforceable Maximum Contaminant Level Goals (MCLGs) under SDWA. MCLs set the maximum allowable concentration of a contaminant in public drinking water systems, while MCLGs represent the level at which there is no known or expected risk to human health. MCLGs are generally set to lower, more stringent levels since MCLs also consider the types and costs of treatment technologies available to public drinking water systems. Under EPA’s proposal, the MCLs for PFOA and PFOS will remain at 4 parts per trillion (ppt) and 0 ppt for MCLGs.  

A Long Road for Final PFAS MCLs 

The establishment of MCLs was an important regulatory milestone in a process that originated more than two decades ago. In the early 2000s, EPA began reexamining the manufacture and use of certain PFAS, and some industries followed suit. In 2009, EPA established non-enforceable health advisories (HAs) for PFOS and PFOA, with subsequent revisions in 2016 and again in 2022. In 2021, EPA reached a final determination to regulate PFOA and PFOS under the SDWA, thus paving the way for publishing draft MCLs/MCLGs in March 2023 and final MCLs/MCLGs in April 2024. Details on the new limits and how they changed from the March 2023 draft version can be accessed on EPA’s NDPWR page. 

Proposed Changes to PFAS MCL Implementation 

In addition to reducing the number of PFAS MCLs and overall scope of the rule, EPA said in its most recent announcement that the agency intends to propose extending the compliance date from 2029 to 2031. This is to allow more time for the public drinking water systems to implement rule provisions, EPA said. The agency indicated that states seeking primacy for rule implementation could ask for additional time as well. Also in line with reducing impact on the regulated entities is the intent of establishing a federal exemption framework and enhanced outreach to rural and small communities, as well as technical and funding resources. The changes are to be captured in a proposed rule this fall, with the anticipated finalization in spring 2026.  

How Does PFAS MCLs News Impact You? We Can Help. 

We will continue to monitor this important development on PFAS MCLs and keep you updated throughout. Please be on the lookout for additional articles on this topic. Meanwhile, if you have PFAS-related questions, concerns, or challenges, drop your information into our contact form, and we’ll schedule time to discuss how you can prepare for and manage PFAS-related regulations.