State Water Resources Control Board Identifies PFAS Maximum Contaminant Levels as its Highest Priority Drinking Water Standards for 2025
By Amilia Glikman, Lobbyist
Overview
On February 19, 2025, the State Water Resources Control Board (“State Board”) unanimously adopted State Board Resolution No. 2025-0006 (“Resolution”) establishing its drinking water priorities for the 2025 calendar year.[1] In its Resolution, the State Board identifies as priorities maximum contaminant levels (MCLs) for six contaminants or groups of contaminants: per- and poly-fluoroalkyl substances (PFAS), disinfection byproducts, arsenic, N-Nitrosodimethylamine (NDMA), styrene, and cadmium and mercury.[2]
The State Board’s 2025 list of priority MCLs remains essentially the same as its 2024 list, with two notable exceptions: (1) hexavalent chromium, the MCL for which was adopted in 2024, was removed from the list; and (2) disinfection byproducts, the MCL for which was elevated from the lowest priority in 2024 to the second highest priority in 2025.
Proposal to Address PFAS Regulations
With the adoption of the hexavalent chromium MCL in 2024, the MCLs for PFAS are now the State Board’s highest priority,[3] particularly in light of the United States Environmental Protection Agency’s (USEPA) adoption of federal MCLs for six PFAS substances in 2024 under the Biden Administration.[4] During the State Board hearing, Division of Drinking Water (DDW) staff outlined its proposal to address the regulation of PFAS in drinking water in two stages. Because California is required by federal law to adopt federal MCLs, the first stage involves adopting federal requirements, with limited adjustments (e.g., for monitoring locations, etc.).[5]
The second stage involves adopting California-specific regulations, which DDW characterized as a more comprehensive regulatory approach using the option to adopt a treatment technique in lieu of an MCL.[6] Given the vast number of PFAS substances, this approach would rely on a limited number of PFAS substances as sentinel contaminants. As part of this process, DDW intends to request a public health goal (PHG) for PFHxS in early 2025, continue developing analytical methodologies, and issue a statewide monitoring order to all public water systems to supplement existing monitoring results to complete federal monitoring requirements and identify PFAS substances of particular concern in California for potential PHG requests.[7]
What’s next?
DDW intends to hold a pre-rulemaking workshop for the adoption of PFAS MCLs—presumably the federal MCLs[8]—in August, September, or October 2025 and issue a notice of proposed rulemaking in November or December 2025.
Questions?
For questions about the State Board’s 2025 drinking water priorities or the State Board’s process for establishing drinking water standards, contact KP Public Affairs’ regulatory advocacy professionals: Amilia Glikman (aglikman@ka-pow.com), Jeff Sickenger (jsickenger@ka-pow.com), and Olivia Wright (owright@ka-pow.com). For more information about Amilia, Jeff, and Olivia, visit KP Public Affairs’ website at https://www.kppublicaffairs.com/team.
Sources
[1] Although not discussed in this article, the State Board also identified other 2025 priorities, including, but not limited to, detection limits for reporting purposes (DLRs), notification and response levels, primacy package approvals, and financial assurance. Notably, of the State Board’s 2025 drinking water priorities, only the PFAS MCLs are identified in the State Board’s Draft 2025 Strategic Work Plan (Mar. 2025).
[2] California Health & Safety Code section 116365, subdivision (h), requires the State Board, by March 1 of every year, to provide notice of each primary drinking water standard it proposes to review that year.
[3] In 2024, the State Board identified MCLs for perfluoro-octanoic acid (PFOA) and perfluoro-octane sulfonic acid
(PFOS) as its second highest MCL priority. See Resolution No. 2024-0009.
[4] See USEPA, Final PFAS National Primary Drinking Water Regulation (Apr. 10, 2024).
[5] See USEPA, Primacy Enforcement Responsibility for Public Water Systems.
[6] California Health & Safety Code section 116365, subdivision (j), allows the State Board to require the use of a specified treatment technique in lieu of an MCL if the State Board “determines that it is not economically or technologically feasible to ascertain the level of [a] contaminant.”
[7] According to DDW, it has been laying the foundation for both stage one and two through the issuance of monitoring orders to water systems as recently as March 2024 and by collaborating with the California Department of Public Health (CDPH) on the California Regional Exposure (CARE) Study. The CARE Study is being administered by Biomonitoring California, which is a collaboration between CDPH, the Office of Environmental Health Hazard Assessment, and the Department of Toxic Substances Control. The goal of the study is to measure and compare environmental chemicals, including PFAS, in California residents to support efforts to reduce chemical exposure and improve public health.
[8] The second stage—California-specific PFAS MCLs—is identified by DDW as a “future year priority.”
