Proposed MCL for Hexavalent Chromium before the State Water Resources Control Board

Last summer, the Board’s Division of Drinking Water Standards announced that they would proceed with the new maximum contaminant level (MCL) for Chrom-6 at 10 parts per billion. The new standard is substantially lower than what the latest research shows is needed to protect public health. CLFP pushed for the Office of Environmental Health Hazard Assessment (OEHHA) to update the Public Health Goal (PHG) used to establish the proposed MCL.

California’s Safe Drinking Water Act (SDWA) requires drinking water standards to be adopted through a transparent process, based on the best available science. This PHG does not comply with that standard. In fact, since the PHG was established in 2011, dozens of studies have been published proving the health values of the current MCL of 50 ppb ultimately legitimizing this standard. Furthermore, The World Health Organization has set their drinking water guidelines at 50 ppb. The SDWA also requires OEHHA to review a PHG every 5 years, and the Chrom-6 PHG was last reviewed in 2011. The PHG process was started in both 2016 and 2023, but was never finished. At that point, the Board should have suspended the MCL-rulemaking process pending the completion of the PHG. This would have allowed the Board to evaluate the impact on water systems, industry, and affordability to customers.

The new standard will undoubtedly increase water costs for water providers and rate payers. In 2021, the Board estimated that implementing solutions for systems that cannot meet the standard would cost up to $10.3 billion over a 5-year period. This, in addition to other increased drinking water standards, will exponentially drive-up costs for industry as the Board is currently developing drinking water standards for the following constituents: Arsenic, PFAS chemicals, N-nitroso-dimethylamine (NDMA), Disinfection byproducts, Styrene, Cadmium, and Mercury.

Senator Padilla (D – San Diego) has introduced a bill, SB 1065, which would authorize the Board to grant an extension of up to 3 years to achieve compliance with the Chrome-6 drinking water standard. CLFP is supporting this measure with various other stakeholders and has asked if the other constituents (listed above) can be incorporated into the 3-year extension as well.

CLFP will be attending the Board’s hearing next week and will testify to the effects of this new standard on our membership. If you have any questions, please contact Katie: katie@clfp.com.