The city’s drinking water met federal and state safety standards last year, but Vacaville is dealing with a new, tougher regulation on a known carcinogen. However, the California State Water Resources Control Board, effective Oct. 1, adopted a new regulation setting the maximum contaminant level for hexavalent chromium, which was detected in city water at levels that exceeded that new standard, the 2024 Annual Water Quality Report released Tuesday states. “Hexavalent chromium is a heavy metal that has been used in industrial applications and found naturally occurring throughout the environment. While chromium can exist in a nontoxic, trivalent form, the hexavalent form has been shown to be carcinogenic and toxic to the liver,” the state Water Resource Control Board reported. “We are working to address this exceedance and comply with the (maximum contaminant level),” the city stated in the report. … In the meantime, the city reported the water system is safe.