Pennsylvania Adopts PFAS MCLs

On January 14, 2023, the Pennsylvania Department of Environmental Protection (DEP) published final maximum contaminant levels (MCLs) for Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS) as follows:

PFOA: 14 parts per trillion (ppt)
PFOS: 18 ppt

Compliance monitoring will begin January 1, 2024 for systems serving a population over 350. Initial monitoring will be four quarterly samples at entry points to the distribution system. Detection above the minimum reporting level (MRL) will trigger repeat monitoring. DEP has set the MRL at 5 ppt for both PFOA and PFOS.

Link to DEP press release:

Link to Pennsylvania Bulletin with the PFOA and PFOS MCLs:

In the Pennsylvania Bulletin, the background information on PFAS begins on page 333. Actual rule language begins on page 361. The new PFAS MCLs are presented at the bottom of page 362, and the monitoring requirements are presented on page 365.

Note: In October 2022, the federal Environmental Protection Agency (EPA) submitted their draft proposed MCLs for PFOA and PFOS to the Office of Management and Budget (OMB) for review. As of today, the proposed MCLs are still under review at OMB. EPA published a “Regulatory Determination” to set MCLs for PFOA and PFOS in March 2021. Once they published that Regulatory Determination, that triggered deadlines under the Safe Drinking Water Act to publish the proposed MCLs within 24 months (by March 31, 2023) and to publish final MCLs 18 months after that (September 2024). EPA’s intent has been to publish the proposed MCLs by the end of 2022 and publish final MCLs by the end of 2023.