PA Advances Rule Limiting Drinking Water Contaminant PFAS

In October 2022, Pennsylvania's Environmental Quality Board (EQB) voted in favor of adopting a new rule that limits the amount of "forever chemicals" allowed in public drinking water. The EQB, established in 1970, is the independent board that adopts all of the PA Department of Environmental Protection's (DEP) regulations. The new regulations are now in the Independent Regulatory Review Commission (IRRC) process.

If approved by IRRC, the rule would include limits on perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) to be protective of adverse developmental and immune system effects, respectively. The regulated chemical compounds are part of a larger group of synthetic chemicals known as Per and polyfluoroalkyl substances (PFAS). PFAS chemicals have been manufactured and in use since the 1940s.

The rule establishes a maximum contaminant level (MCL) for each compound, as listed below. This means that all 3,117 community, nontransient bottled, vended, retail, and bulk hauling noncommunity water systems must monitor for these two chemicals and keep track of their running annual average levels. If their running annual average exceeds the MCL then they will be in violation and must report the results on their Annual Drinking Water Quality Reports and through public notice efforts.

The new rule also includes an MCL goal (MCLG) for the PFOS and PFOA. The goal, while not enforceable, is the level at which known or expected human health risks exist. MCLs are typically set higher than MCLGs when it is not feasible to test for or treat to reduce a chemical at the levels in the goal. Sometimes the technology does not exist, or it is not affordable.

The new rule:

• PFOA – MCL 14 ng/L or ppt – MCLG 8 ng/L or ppt – Protective of adverse developmental effects (including neurobehavioral and skeletal effects)
• PFOS – MCL 18 ng/L or ppt – MCLG 14 ng/L or ppt – Protective of adverse immune system effects (including immune suppression)

*ng/L = nanograms per liter, ppt = parts per trillion – these are equivalent units

This would be the first time that Pennsylvania has established an MCL independent of the federal government. All other MCLs for public drinking water in Pennsylvania are those of the United States Environmental Protection Agency (EPA). Currently, PFOA and PFOS are not regulated in drinking water at the federal level.

In 2016, EPA established a combined lifetime Health Advisory Level (HAL) for PFOA and PFOS of ppt. This HAL is not an enforceable regulatory standard. In the summer of 2022, they modified that health advisory and are currently publishing an interim HAL for PFOA of 0.004 ppt and for PFOS of 0.02 ppt. Both of these near-zero levels reflect newly available science that indicates some negative health effects may occur even at such low levels of PFOS and PFOA, due to lifetime exposure to them. These levels, however, are below any means of detection using the technology available at this time.

This new rule would not apply to private water supplies in Pennsylvania. If you get your drinking water from a private well, spring, or cistern you are responsible for your own testing and treatment of your drinking water. For more information, you can refer to Penn State Extension's resources for private water supply users.

*This article has been updated to reflect that the rule is not yet effective and still needs to complete the PA IRRC process.