Santa Rosa Water currently operates two groundwater production wells, three emergency wells and one landscape irrigation well. Groundwater pumping from the two production wells is typically limited to the late spring through early fall months (usually May through October) when peak demand occurs, and supplies approximately 5 - 10% of the City's annual water demand.

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.
To observe long term trends in groundwater storage and water quality, Santa Rosa Water monitors groundwater very closely to ensure sufficient water supply and quality of that supply.

Groundwater Storage

Santa Rosa monitors groundwater storage through a Monitoring Network semi-annually using the California Statewide Elevation Monitoring (CASGEM) program developed by the Department of Water Resources in response to Senate Bill x7-6, CASGEM enables monitoring of groundwater elevations in all groundwater basins and sub-basins in California, including 32 in the general Santa Rosa area.

Groundwater Quality

In order to protect the quality and beneficial reuse of groundwater, Santa Rosa, as well as other cities and water districts in the region, developed a Salt and Nutrient Management Plan in 2013
 to manage salts, nutrients and other significant chemical compounds on a watershed or basin-wide basis in compliance with the State of California Recycled Water Policy

Santa Rosa Valley Groundwater Basin

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

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.

Sustainable Groundwater Management

Groundwater management provides an overarching strategy for managing groundwater resources within a groundwater basin. Effective management integrates groundwater and surface water protection and management with conservation, reuse and enhanced recharge strategies to increase water supply reliability and sustainability.

To effectively and responsibly manage our groundwater Supply, the City developed a Groundwater Master Plan (PDF), which includes:
  • Recommendations for an emergency groundwater supply plan;
  • Development of a key well monitoring network;
  • Conceptual evaluation of aquifer storage and recovery;
  • Recommended groundwater policies designed to guide the future role of groundwater and promote balanced use and sustainability for the groundwater resources available to the City
  • Based on these recommended policies, identified specific groundwater projects and programs
Additionally, the City, in collaboration with a 30-member Basin Advisory Board, which included diverse stakeholders who live or work in the Santa Rosa Plain Watershed, developed a Santa Rosa Plain Groundwater Management Plan (PDF) in 2014 to comply with AB 3030 and SB 1938. The Plan is an integrated strategy to increase water supply reliability, minimize adverse impacts to groundwater, enhance local management of groundwater resources, and increase economic opportunities through available state grant funding programs.

Sustainable Ground Water Management Act

On September 16, 2014, the Governor signed a package of bills known as the 2014 Sustainable Groundwater Management Act, that will change groundwater management in California.  The legislation, which took effect on January 1, 2015, gives local agencies the means to manage groundwater basins in a manner that is sustainable over the long-term and provides authority for the State to step in should basins not be managed sustainably.

Adopting the Santa Rosa Plain Groundwater Management Plan prior to the new law taking effect significantly advanced the region’s ability to comply with the new legislation by establishing a robust data collection and monitoring program, promoting, studying and implementing programs and projects aimed at sustaining the basin’s groundwater resources, and fostering stakeholder coordination activities.