The City of Ripon is preparing to address stricter water quality standards after California set the nation’s first specific regulatory limit for hexavalent chromium—better known as Chromium-6—in drinking water. State officials established the new threshold at 10 parts per billion (ppb) in October 2024, a move that comes as part of ongoing efforts to protect public health from potential long-term risks associated with certain contaminants.

Chromium, a naturally occurring element found in rocks, soil, plants, and animals, appears in two principal forms in groundwater: trivalent chromium (Chromium-3) and hexavalent chromium (Chromium-6). While low levels are common, long-term exposure to elevated concentrations of Chromium-6 has been linked to health concerns, prompting the state’s recent action.

Recent routine monitoring revealed that one of Ripon’s groundwater wells, located at Mistlin Sports Park, reported an average Chromium-6 level of 10.7 ppb between late February and mid-November 2025. That’s slightly above California’s newly established Maximum Contaminant Level, or MCL. Under the new rules, Ripon has until October 1, 2027, to bring the well into compliance.

City officials emphasize that this is not an emergency and that the water remains safe for everyday use. “Customers do not need to boil their water or change their usual routines,” officials said, noting that the new limit is based on health impacts from long-term exposure rather than short-term consumption.

Ripon’s public works team is now developing a formal compliance plan, which will be submitted to the State Division of Drinking Water for approval. The plan will detail the steps Ripon will take to reduce Chromium-6 levels and meet the state’s deadline. Routine testing and oversight from both city and state agencies will continue to ensure that Ripon’s water supply remains safe and reliable for all residents.

To read the official announcement from the city and to review additional resources, visit www.cityofripon.org.