Groundwater

Santa Rosa Water currently has two groundwater wells that are typically operated in late Spring through early Fall, when peak demand occurs. These wells provide 5-10% of the City's water supply.

What is Groundwater?

Groundwater is the water that soaks into the soil from rain or other precipitation and moves downward to fill cracks and other openings in beds of rocks and sand. Groundwater is stored in aquifers and is extracted through a well drilled into the aquifer. A well is a pipe in the ground that fills with water. This water can be extracted by a pump and used to supply water for drinking, crop irrigation, industrial purposes, and to recharge lakes, rivers and wetlands.
Diagram of groundwater.

Santa Rosa Plain Groundwater Basin


The Santa Rosa Plain Groundwater Basin is one of the largest groundwater basins in the California Department of Water Resource’s North Coast Hydrologic Region.  The Santa Rosa Plain Groundwater Basin has three sub-basins:  Healdsburg, Santa Rosa Plain, and the Rincon Valley.

Santa Rosa is located within the Santa Rosa Plain Sub-basin, where Santa Rosa’s groundwater supply is derived exclusively. The Santa Rosa Plain Sub-basin is approximately 22 miles long and 0.2 miles wide at the north end, approximately 9 miles wide through the Santa Rosa area and about 6 miles wide at the south end near the City of Cotati.
Sustainable Groundwater Management Act Map
The U.S. Geological Survey (USGS), in partnership with the Sonoma County Water Agency, the cities of Santa Rosa, Rohnert Park, Cotati, and Sebastopol, the Town of Windsor, California American Water, and others, conducted a 5-year study of the Santa Rosa Plain Sub-basin to characterize the surface water and groundwater resources of the Santa Rosa Plain Watershed. The study provided a wealth of information and valuable tools for local stakeholders to use to develop the Ground Water Management Plan.