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DEP Involvement

Rulemaking Sets MCLs for PFOA and PFOS

On January 14, 2023, the PFAS MCL Rule was published in the Pennsylvania Bulletin, setting maximum contaminant levels (MCLs) for PFOA and PFOS in drinking water. The rule sets an MCL of 14 parts per trillion (ppt) for PFOA and an MCL of 18 ppt for PFOS. The rule also specifies requirements to ensure compliance with the MCLs, including monitoring and reporting, analytical requirements and approved treatment technologies.

For more information, visit the Bureau of Safe Drinking Water PFAS MCL Rule website.

Program Involvement

Safe Drinking Water

The Safe Drinking Water Program is charged with managing the federally delegated drinking water program and implements both the federal and state Safe Drinking Water Act and associated regulations. This program oversees permits, compliance, and operations as they pertain to public water systems across the Commonwealth.

Cleanup Standards

Products containing long-chain PFAS chemicals leach into the soil and water where they continue to be mobile, highly persistent, and bioaccumulative. It is crucial to remove contaminants from the soil before they migrate into water sources. To achieve this, DEP’s Bureau of Environmental Cleanup and Brownfields drafted new proposed regulatory cleanup standards for soil and groundwater for three compounds in the PFAS family – Perfluorobutane Sulfonate (PFBS), Perflurooctane Sulfonate (PFOS), and Perfluorooctanoic Acid (PFOA). This proposed regulation was adopted by the Environmental Quality Board, DEP’s rulemaking body, on November 19, 2019.

Statewide PFAS Sampling Plan

DEP implemented a plan to sample public water supplies that have elevated potential for contamination, based on proximity to common sources of PFAS, such as military bases, fire training sites, landfills, and manufacturing facilities. The sampling plan collected information from May 2019 through March 2021 (with a temporary hiatus due to the COVID pandemic).

State MCL Considerations

Currently, there is no federal maximum contaminant level (MCL) for PFOA and PFOS. However, Pennsylvania can set an MCL for unregulated contaminants such as PFOA and PFOS. As per the Pennsylvania Safe Drinking Water Act (SDWA), the Environmental Quality Board (EQB) is authorized to adopt MCLs or treatment technique requirements, even in situations where a federal standard has not been set. In order for the EQB to consider adoption of a state MCL, the Department of Environmental Protection (DEP) must provide the necessary science, data, studies, cost to benefit analysis, and justification to support such a proposed MCL. This supporting data is required by Pennsylvania's regulatory review process. This data also is necessary for DEP to be able to defend and enforce the state MCL in a court of law.

DEP completed the following steps prior to initiating the rulemaking to set an MCL:

  • Determined whether the proposed MCL is technically feasible.
    • Researched treatment technologies to adequately and consistently remove PFOA/PFOS to levels below the proposed MCL. DEP has identified acceptable treatment technologies in the proposed rule. As new treatment technologies are developed, they will need to be evaluated for efficacy by a third-party certification organization such as NSF International and potentially undergo pilot testing as well.
    • Determined any simultaneous compliance concerns or unintended consequences with the Safe Drinking Water regulations or other laws of this Commonwealth.
    • Ensured sufficient lab capacity and capability and maintain a state lab accreditation program for PFOA/PFOS. Labs must be able to achieve detection and reporting limits that are below the proposed MCL.
  • Conducted a cost to benefit analysis to support a statewide standard. A state MCL would apply to all PWSs. All systems would be required to conduct routine compliance monitoring. And if levels were found above a state MCL, the system would be required to take any and all actions needed to return to compliance. These potential compliance costs must be quantified.
  • Developed the necessary justification for proposing a standard that is more stringent than EPA.

On January 14, 2022, the PFAS MCL Rule was published in the Pennsylvania Bulletin. For more information on the rule, please visit the Bureau of safe Drinking Water’s PFAS MCL Rule website.