As surface water, such as rain, seeps into the ground, it passes between soil particles and collects in underground reservoirs called aquifers. An aquifer is made up of sand, silt, or other permeable materials that can readily yield water to springs or wells.
The 45-square-mile Westside Basin, a series of aquifers extending from Golden Gate Park in San Francisco southward through San Bruno, is a vital local resource for San Francisco and neighboring communities in San Mateo County.
Groundwater is an important water supply source for other communities throughout the world. In California alone, it provides approximately 40 percent of the state’s drinking water. Our Groundwater Program currently includes two projects plus a Groundwater Stewardship and Management Program.
These projects will provide both local and regional benefits by increasing our water supply reliability, diversifying our water supply portfolio and reduce our dependence on a single source, thus making us less vulnerable to disrupted service from natural disasters such as earthquakes.