Per- and Polyfluoroalkyl Substances (PFAS) Rule
Per- and Polyfluoroalkyl Substances (PFAS) Rule
The Environmental Protection Agency (EPA) finalized the PFAS National Primary Drinking Water Regulation (40 CFR Parts 141 and 142) in April 2024 to reduce per- and polyfluoroalkyl substances (PFAS) exposure in drinking water. The rule contains initial monitoring requirements and sets Maximum Contaminant Levels (MCLs) for six PFAS chemicals: PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS. The rule applies to community and non-transient, non-community water systems.
The Water Quality Control Commission adopted the PFAS Rule under Regulation 11 in August 2025, with a compliance date of April 1, 2027. If you operate a water system, please review the information on this page to ensure compliance with the PFAS rule. The Water Quality Control Division will continue to update this page with resources to assist water systems with the requirements.
Additional Resources
- Use the initial monitoring compliance worksheet to verify that PFAS samples meet the applicable timing requirements.
Data
- Submit all results, including those below the Practical Quantitation Levels (PQLs), in a CSV file via the drinking water portal by April 1, 2027. Please view the instructions on the our website for more information on submitting data.
- Systems that have previously collected PFAS data from other sampling events (e.g., UCMR 5), not included in the table below, may submit the data in one of two ways:
- For sample results analyzed by a certified lab with a reporting level less than the trigger level, submit results using our online CSV specific form (information on reporting sample results) via the drinking water portal.
- If results do not meet the above criteria (e.g., UCMR 5 data), submit results in an Excel file using the division’s online form. Please review the division's guidance document for more information on submitting UCMR 5 results.
Recommendations for keeping the public informed
The division recommends that all public water systems update their customers on all PFAS-related activities, including all PFAS sampling results, including those without PFAS detections, and treatment (if applicable). If water systems detect PFAS levels above the MCL, water systems should inform the public per EPA’s recommendation. Water systems should provide sample results and an explanation of their significance. If you operate a public water system and need further assistance, please use the division’s consumer drinking water notice template, which is available in English and Spanish.