Full Notification

The City of Ripon’s highest priority is to provide safe, reliable drinking water that meets all drinking water standards established by the State of California and the U.S. Environmental Protection Agency. The City’s drinking water supply is routinely tested and the results of those tests are monitored by both the City and the State of California Division of Drinking Water to ensure the concentration of any regulated constituent present in the water does not exceed the allowable regulatory limit, known as the Maximum Contaminant Level (MCL).
 
California has recently adopted a more stringent drinking water standard for Chromium-6.  In October 2024, the State of California established a MCL of 10 parts per billion (ppb) for hexavalent chromium (Chromium-6).  California is the first state in the nation to set a drinking water standard for Chromium-6. Chromium is found naturally in rocks, plants, humans and animals. The most common forms of chromium that occur in natural waters are trivalent chromium (Chromium-3) and hexavalent chromium (Chromium-6). Long-term exposure to elevated levels of Chromium-6 may pose health risks. 
 
Routine water monitoring shows that one City of Ripon groundwater well located at Mistlin Sports Park had an average Chromium-6 concentration of 10.7 ppb during the period from February 25, 2025 to November 18, 2025.  This is above the recently established State MCL which the City of Ripon has until October 1, 2027 to comply with.
 
This is not an emergency. Although recent test results exceed the new State standard for Chromium-6, there is no immediate public health risk.  Customers do not need to take any special precautions, such as boiling water or limiting water use.  The State’s new regulatory limit is based on potential health effects from long-term exposure, not short-term consumption.
 
The City of Ripon is actively working toward compliance with the new regulation.  A compliance plan and implementation timeline are currently being developed and will be submitted to the State of California for review and approval.  This plan will outline the steps the City will take to achieve compliance with the Chromium-6 MCL prior to the October 2027 compliance deadline.
 
ADDITIONAL RESOURCES
City of Ripon:  Public Notification Letter (December 2025)
https://www.cityofripon.org/DocumentCenter/View/1622/Chromium-6-Public-Notification-Letter
 
State Water Board:  Information Regarding Chromium-6
https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Chromium6.html
 
State Water Board:  Frequently Asked Questions Regarding Chromium-6
https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/docs/cr6-mcl-public-faq.pdf
 
For more information, please contact James Pease at 209-599-2108 or [email protected].