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County Administrator's Office

For Immediate Release

Sonoma County unveils resources for well owners impacted by drought

Santa Rosa,CA | January 14, 2022

Sonoma County, in collaboration with the North Coast Regional Water Quality Control Board, unveiled new resources today to help private well owners ensure their water is safe to drink amid changes in local groundwater tables as a result of the drought.

Following two years of drought, groundwater tables are lower than normal in some parts of Sonoma County. As a result, some wells may be experiencing increased concentrations of naturally occurring substances that can be harmful to human health, said Christine Sosko, the county’s director of Environmental Health.

“Well owners should test their well water to ensure it is safe to consume,” Sosko said. “Testing for naturally occurring contaminants is highly recommended to ensure your well water is safe. If tests detect unhealthy substances, seek the advice of a private water treatment expert on the best way to remedy the problem.”

Environmental Health has partnered with the North Coast Regional Water Quality Control Board, the Sonoma County Water Agency and Permit Sonoma to create a digital resource hub with tools to help Sonoma County well owners. The website includes information on potential contaminants in well water and their impact on health; maps with information on groundwater quality in Sonoma County; information on the type and frequency of tests needed to keep wells safe; a list of laboratories certified to test groundwater for chemical and bacteriological contaminants; information on water treatment devices; and resources for well owners experiencing a decline in groundwater levels.

The resource hub can be viewed at

“The Regional Water Board applauds the county for making these resources and guidelines available to private well owners in Sonoma County. Testing the quality of private drinking water wells is a critical component to protecting public health,” said Matt St. John, executive officer of the North Coast Regional Water Board.

Groundwater is an essential resource in Sonoma County, home to roughly 45,000 water wells, the most per capita of any county in California. Water quality is dependent on many factors, including the lithology of the aquifer, well construction, location, maintenance and the amount of rainfall. 

“Falling groundwater levels caused by drought conditions may increase levels of naturally occurring minerals in shallow groundwater that supplies drinking water to private domestic wells,” said Christopher Watt, senior engineering geologist with the North Coast Regional Water Board.

“Climate change will continue to stress our water resources, and as we respond and adapt to its challenges, we must actively identify any risks and vulnerabilities in our critical water infrastructure,” said Lynda Hopkins, Sonoma County Fifth District Supervisor.

Despite atmospheric rivers that brought much-needed rain to Sonoma County in October and December, private well owners should also be making every effort to conserve water. Preserving groundwater stored in underground aquifers will help ensure well owners have continued access to water if the region’s two-year drought continues into 2022. Since the beginning of the 2019-2020 water year on Oct. 1, 2019, Santa Rosa has received only 54 inches of rain, 30 percent short of its historical average, according to the National Weather Service. Historically, it has received 77 inches of rain during the same period.