States Leading Federal Action
Several states established PFAS drinking water standards before the EPA completed its federal rules, creating a patchwork of different regulatory levels and compound coverage across the country. Massachusetts established PFAS6 (six PFAS compounds) maximum contaminant levels in 2020. Michigan implemented standards for seven PFAS compounds. Vermont, Connecticut, and New Hampshire established their own standards. These state rules required compliance before the 2024 federal MCLs took effect.
Variation in Covered Compounds
State PFAS regulations differ not only in concentration limits but in which compounds they cover. Federal regulation covers six specific PFAS: PFOA, PFOS, PFHxS, PFNA, HFPO-DA (GenX), and PFBS. Some states cover additional compounds; others use a sum-of-PFAS approach that applies a combined limit to a broader list of compounds. Water systems operating across state boundaries or subject to both state and federal standards must meet the more stringent applicable requirement for each compound.
State Groundwater Standards
PFAS groundwater standards — distinct from drinking water standards — are established by state environmental agencies and apply to cleanup of contaminated sites, stormwater discharges, and remediation design goals. These standards vary considerably in both the compounds covered and the concentration levels adopted, reflecting different risk assessment methodologies and exposure assumptions. California, New Jersey, and several other states have established relatively comprehensive PFAS groundwater guidance that has influenced remediation practice nationally.
Monitoring and Reporting Requirements
State PFAS monitoring requirements go beyond what federal UCMR (Unregulated Contaminant Monitoring Rule) requires, often specifying more frequent sampling, a broader list of compounds, and lower reporting thresholds. Understanding the applicable monitoring requirements in each state is essential for water utility compliance planning. States are also increasingly establishing notification requirements when PFAS is detected above specified levels, triggering communication obligations to customers.