Drinking Water Regulation Update - Poly-fluoroalkyl Subtances (PFAS)

Under the Safe Drinking Water Act, the Environmental Protection Agency (EPA) has the authority to set enforceable National Primary Drinking Water Regulations for drinking water contaminants and require monitoring of public water systems. On April 10^th 2024, the EPA announced its Final National Drinking Water Regulation for six Per- or poly-fluoroalkyl substances, or PFAS. The standards under the final regulation are:

• A Maximum Contaminant Level Goal (MCLG), a non-enforceable health-based goal, for PFOA and PFOS of zero. 
• Maximum Contaminant Levels (MCLs) for PFOA and PFOS, individually, of 4.0 parts per trillion.
• MCLGs and MCLs for PFNA, PFHxS, and “GenX Chemicals” of 10 parts per trillion.
• A Health Index for any mixture of two or more of the following PFAS: PFNA, PFHxS, PFBS, and “GenX Chemicals.”

EPA’s new national regulation decreases the New Hampshire PFAS drinking water standards that were established in July 2020. Information on the National Drinking Water Regulation can be found at: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas. The Exeter Water Department sampled its drinking water treatment facilities for the six compounds included in the new EPA rule in January 2024. The results showed levels of “non detect” at both facilities. A non-detect concentration means the compound was not at a level high enough for the laboratory equipment to detect.

* - These 4 to be regulated as a combined Hazard Index based on Health Based Water Concentration ratios.
# - The Health Based Water Concentration value for PFBS to be used in the Hazard Index is 2,000 ppt.