Nov 22, 2021

Sonoma County, California, Backs Well Water Regulations

The plans are due for submission to the state Department of Water Resources in January. 


Sonoma County, California, supervisors unanimously endorsed plans to guide use and governance of groundwater relied on by rural residents, farmers and cities

According to North Bay Business Journal, the plans are required by a 2014 state law after California’s past drought and will eventually include well water use fees in three basins underlying the Santa Rosa Plain, Sonoma and Petaluma valleys.

The plans are due for submission to the state Department of Water Resources in January. 

“This is a very big deal,” said board Chair Lynda Hopkins, reported North Bay Business Journal. “First time ever the state of California regulated groundwater.”

Official approval of the plans must still come from the Groundwater Sustainability Agencies in charge of each basin, which is anticipated in December.

The fees that will be charged to well water users have not been decided, however.


Each of the three basins is governed by a groundwater sustainability agency with a board of elected or appointed members from agencies, including a representative from both the county and Sonoma Water. Sonoma Water delivers Russian River water to more than 600,000 Sonoma and Marin county residents.

According to the plans, the agencies must achieve no significant drop in groundwater tables year-to-year by 2042 and maintain sustainability to at least 2072, reported North Bay Business Journal.

“Compared to the critically overdrafted groundwater basins in the Central and San Joaquin valleys, the three Sonoma County basins are in relatively good shape, but still face challenges,” said a staff report from Sonoma Water and Permit Sonoma, the county’s planning and building department, reported North Bay Business Journal.

There are gaps in data in all three basins, according to the report, particularly about groundwater pumping and the depletion of connected creeks and streams. Data on seawater intrusion and depletion of surface water is also limited. 

In Sonoma Valley, groundwater storage is declining by about 900 acre feet a year. The three plans will focus on filling data gaps.

The first five-year costs of implementing the plans in Petaluma Valley and the Santa Rosa Plain are estimated at $1.1 million annually, according to the report. This does not include capital costs for projects. In Sonoma Valley, the five-year implementation costs are about $1.2 million annually, as well as an estimated $8.6 million in capital costs.

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