Hexavalent Chromium
Chromium-6 (Hexavalent Chromium)
Chromium is an odorless and tasteless metallic element. Chromium is found naturally in rocks, plants, soil, volcanic dust, and animals. The most common forms of chromium that occur in natural waters are trivalent chromium (chromium-3) and hexavalent chromium (chromium-6). Chromium-3 is an essential dietary element. It is found in many vegetables, fruits, meats, grains, and yeast. Chromium-6 occurs naturally in the environment from the erosion of natural chromium deposits. Chromium-6 can also be produced by certain industrial processes.
In California, chromium-6 is currently regulated in drinking water under the Total Chromium state Maximum Contaminant Level (MCL) of 50 parts per billion (ppb). California is the only state to have set its own total chromium MCL. In 2014, the California State Water Resources Control Board Division of Drinking Water adopted a new chromium-6 MCL of 10 ppb; however, in August 2017 they rescinded the regulation due to adequate documentation on the economic feasibility of meeting the standard.
Routine water quality testing has confirmed that the City of Santa Cruz Water Department’s (SCWD) water supply is safe to drink. Historically, low levels of chromium-6 have been detected in the treated water supply due to native groundwater and surface water concentrations. The chromium-6 found in SCWD’s source water is naturally occurring and does not come from industrial waste. The most recent chromium-6 results are provided in the 2022 CCR.