California’s compliance schedule for the state’s 10 µg/L hexavalent chromium drinking-water standard is entering its first implementation phase. Public water systems with 10,000 or more service connections must comply beginning October 1, 2026, followed by smaller systems in 2027 and 2028. California systems should review their monitoring results, applicable compliance date and any required compliance-planning activities with their regulator and laboratory.

California Waterboards Cr 6 update