PFAS in Pennsylvania

March 25, 2022

Establishing MCLs for PFAS in Pennsylvania

About the author:

Lisa Daniels is the director of the Bureau of Safe Drinking Water within the Pennsylvania Department of Environmental Protection. Daniels can be reached at [email protected].

Like many states, Pennsylvania has identified concerns with per- and polyfluoroalkyl substances (PFAS) in our drinking water supply, emerging contaminants whose health and environmental impacts are still not well understood. The potential impacts are huge considering there are close to 8,400 public drinking water systems in Pennsylvania, serving more than 11.3 million customers.

The Pennsylvania Department of Environmental Protection’s (DEP) Safe Drinking Water Program first became aware of PFAS in 2013, when the U.S. EPA released its Third Unregulated Contaminant Monitoring Rule (UCMR 3), which required monitoring for 30 unregulated contaminants, including six PFAS. As of this writing, the EPA has not initiated its process for establishing MCLs or MCLGs for PFAS under the federal Safe Drinking Water Act.

PFAS substances were developed in the 1940s and are found in many commonly used items, like clothing and fire-fighting foam. When these substances are released to the environment, they find their way into soil and waterways, reaching sources of drinking water.

Companies began phasing out the production and use of several PFAS substances in the early 2000s. Despite the phase-out, contamination has been identified all across the country and in at least 15 sites in Pennsylvania.

At the direction of Pennsylvania Gov. Tom Wolf, in 2018, an executive order established the PFAS Action Team. The governor tasked this multi-agency action team with developing a comprehensive response to identify and eliminate sources of contamination, ensure drinking water is safe, and manage environmental contamination.

In early 2019, Pennsylvania DEP’s Safe Drinking Water Program began work on the PFAS Sampling Plan and Toxicology Services Contract. It identified potential sources of PFAS contamination (PSOC), such as military bases, fire training sites and landfills, and then overlaid the GIS data layer with the location of public water system sources.

Of the 412 samples collected, PFOS and PFOA were most common, being detected at 103 (25%) and 112 (27%) sites, respectively. Two of the results were above EPA’s health advisory level (HAL) for PFOS and PFOA of 70 parts per trillion (ppt). Of the sites with detections, eight PFAS were detected: PFOS, PFOA, PFNA, PFHxS, PFHpA, PFBS, Perfluorohexanoic acid (PFHxA) and Perfluoroundecanoic acid (PFUnA). Results were non-detect for the other 10
PFAS tested.


In December 2019, DEP executed a toxicology services contract with Drexel University to review other state and federal agency work on MCLs. Deliverables include the “Drexel PFAS Workbook” and “MCLG Drinking Water Recommendations for PFAS in the Commonwealth of PA” (MCLG Report).

DEP moved forward with a draft proposed rulemaking to set MCLs for select PFAS. In November 2021, the EQB approved the proposed rule to set maximum contaminant levels (MCL) for PFOA and PFOS. The proposed rule will set stricter limits compared to the EPA’s Combined HAL for PFOS and PFOA.

About the Author

Lisa Daniels