Defense Digest, Vol. 28, No. 12, December 2022

Pennsylvania Adopts New Drinking Water Standards for So-Called “Forever Chemicals”

Key Points:

  • Pennsylvania Environmental Quality Board amendments to 25 Pa. Code Chapter 109 (relating to Safe Drinking Water) bring Pennsylvania in line with other states that have set drinking water standards for “forever chemicals.”
  • The new Pennsylvania standards are still far higher than the standards set by the US EPA.

On October 12, 2022, the Pennsylvania Environmental Quality Board recommended final-form amendments to 25 Pa. Code Chapter 109 (relating to Safe Drinking Water), establishing maximum contaminant level goals (MCLGs) and maximum contaminant levels (MCLs) for two contaminants, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), that are part of a larger group of per- and polyfluoroalkyl substances, known as “PFAS.” The amendments would apply to community, non-transient non-community, bottled, vended, retail, and bulk hauling water systems. The final-form amendments would also establish other requirements to demonstrate compliance with the MCLs, including monitoring requirements, analytical requirements, reporting and public notification requirements, and acceptable treatment techniques.

PFAS are commonly referred to as “forever chemicals” because they breakdown very slowly over time. According to the EPA, current scientific research suggests that exposure to high levels of certain PFAS may lead to adverse health effects. However, research is still ongoing to determine how different PFAS can lead to a variety of health effects. Research is also trying to better understand the health effects associated with low levels of exposure to PFAS over longer periods of time.

Prior to the amendments, Pennsylvania did not regulate PFOA or PFOS in drinking water, so there were no MCLGs or MCLs. In 2016, the EPA set a Combined Lifetime Health Advisory Level (HAL) for PFOA and PFOS of 70 parts per trillion. However, in June of this year, the EPA lowered the interim HALs for PFOA and PFOS to 0.004 and 0.02 parts per trillion, respectively.

This was a significant reduction from the prior HALs for both PFOA and PFOS and, according to the EPA, was based on “new science and consider lifetime exposure, [which] indicate that some negative health effects may occur with concentrations of PFOA or PFOS in water that are near zero.” The minimum reporting level based on today’s technology is 4 parts per trillion for both PFOA and PFOS, meaning that any detection will be an exceedance under the new HALs. It should be noted that HALs are not enforceable and are intended to be “advisory” only. HALs often set the stage, however, for further action by the EPA in the form of formal rule making.

The new Pennsylvania MCLGs and MCLs for PFOS and PFOA are more stringent than the prior interim HALs set by the EPA but far less stringent than the updated HALs. Specifically, Pennsylvania set an MCGL for PFOA of 8 parts per trillion and an MCL of 14. The MCGL for PFOS is 14 parts per trillion, and the MCL is 18.

MCLGs, like the EPA’s HALs, are for guidance only and are not enforceable. They are essentially an aspirational goal based on a review of available scientific literature. The MCGL allows for a margin of safety, as they limit the level of a contaminant to a concentration below which there is no known health risk. The MCL, on the other hand, is enforceable and sets the legal threshold for the highest concentration of the contaminant in drinking water. Thus, the legally enforceable limits set by the Pennsylvania Environmental Quality Board for PFOS and PFOA are 14 and 18 parts per trillion, respectively.

The final-form amendments announced by the Pennsylvania Environmental Quality Board highlight the uncertain nature of regulatory enforcement of PFAS in drinking water. The new amendments bring Pennsylvania in line with other states that have set drinking water standards for PFAS. Currently, only eight states regulate PFAS in drinking water. Those states set MCLs for PFOA ranging from 8 to 20 parts per trillion and for PFOS ranging from 10 to 20 parts per trillion. Thus, Pennsylvania’s new standards are consistent with those states but are far higher than the new HALs set by the US EPA.

*Kevin is a shareholder in our Mount Laurel, New Jersey, office. He can be reached at 856.414.6057 or



Defense Digest, Vol. 28, No. 12, December 2022, is prepared by Marshall Dennehey to provide information on recent legal developments of interest to our readers. This publication is not intended to provide legal advice for a specific situation or to create an attorney-client relationship. ATTORNEY ADVERTISING pursuant to New York RPC 7.1. © 2022 Marshall Dennehey. All Rights Reserved. This article may not be reprinted without the express written permission of our firm. For reprints, contact