San Francisco Public Utilities Commission
Skip to page body Home Customer Service How To Environment Projects & Programs About Us


Regional Groundwater Storage and Recovery (WSIP)

Click to see the entire project map.

See the entire project map here.

Regional Groundwater Storage & Recovery (GSR) Project Update
The GSR project, will build 16 well facilities including chemical treatment equipment, tanks, pumping systems, and associated pipelines. In January 2015, the SFPUC awarded the $42.9 million construction contract to Ranger Pipelines, Inc. This Project will start construction in spring 2015 and anticipates completion in summer 2018.

To extract the stored groundwater, 16 recovery wells and well stations including chemical treatment equipment, tanks, pumping systems and associated pipelines are to be installed as part of the GSR project. The wells will be able to extract the stored groundwater at a rate of up to 7.2 million gallons per day, which would serve up to 24,000 households. The project is designed to protect against drought, and will provide enough of a water savings account to help ensure resilience through a multi-year dry spell lasting up to seven and a half years. The water quality from this stored supply will meet the California Department of Public Health requirements for drinking water supplies.

A Water Savings Account for Protection Against Drought
The GSR project is part of our Water System Improvement Program (WSIP) and will benefit over 2.6 million people and businesses in the Bay Area by providing a local supply of water for use in times of drought. By storing water in wet years, when water supply is sufficient, this project builds a water savings account that can be tapped during dry years or in emergency situations such as an earthquake. The project will help to meet our dry year water supply needs. Without this project, we cannot fulfill the region's dry year water supply needs for its residents and would need to increase mandatory rationing above currently projected levels.

A Regional Approach to Drought Protection

California Water Service Company, City of Daly City, City of San Bruno and SFPUC celebrate signing of operating agreement.

A landmark agreement between the SFPUC and three San Mateo County organizations was finalized and signed in December 2014 to ensure long-term management and sustainability of the South Westside Groundwater Basin. The partnership with SFPUC, City of Daly City, City of San Bruno and California Water Service Company allows these agencies to operate the basin and provide a new 20 billion gallon regional dry year groundwater supply. These San Mateo County agencies provide drinking water from two sources, local groundwater from the South Westside Groundwater Basin and surface water supplies from the SFPUC. Every drop of water stored by this project helps our region during times of drought.

                   Regional Groundwater Map
This project includes the installation of up to 16 new recovery well facilities in northern San Mateo County.


How Would the Proposed Project Work?
The concept of groundwater storage and recovery, also known as “conjunctive water management”, consists of storing water in wet years and recovering that water for use during dry years. As part of this project, surface water will be used instead of groundwater in wet years. This will create a savings account of groundwater stored in the aquifer by allowing it to recharge through rainfall and decreased pumping. In dry years, when less surface water is available, the saved water will be pumped from the new groundwater well recovery facilities. This local savings account of water will be made available during drought conditions or emergencies such as an earthquake. The GSR project will increase the water supply reliability for over 2.6 million Bay Area residents and businesses that rely on the Hetch Hetchy Regional Water System for all or part of their water supply.

In wet years, municipal pumping is decreased and groundwater fills the available aquifer storage space.
In dry years, groundwater is pumped from storage – the “water savings account”.


Groundwater Storage Around the Bay
In the Bay Area alone, similar programs are being implemented by the Santa Clara Valley Water District (serving Campbell, Cupertino, Gilroy, Los Altos Hills, Milpitas, Monte Sereno, Morgan Hill, Mt. View, Palo Alto, San Jose, Santa Clara, Saratoga and Sunnyvale, and the towns of Los Altos and Los Gatos), the Alameda County Water District (serving Fremont, Newark, and Union City) and the Zone 7 Water Services Agency (serving Livermore, Pleasanton and Dublin). These programs have been operating successfully for decades.