Diversifying Our Water Supply
On an average day, the City of San Francisco – its residents, businesses, and visitors – consumes about 70 million gallons of water. This water is supplied solely by the Hetch Hetchy Regional Water System. Developing local groundwater can help diversify our supply portfolio and ensure we have a local source for water should a drought, earthquake or other disaster interrupt our Hetch Hetchy supply.
A Vital Project that Brings Multiple Benefits
The San Francisco Groundwater Supply Project is an important component of the Water System Improvement Program and provides both local and regional benefits.
- Local: Our environment and our city face many unknowns in the future from possible drought, earthquake and climate change. A local water source will give us more control over the use and operation of our water supplies.
- Sustainable: Groundwater is a renewable water source that is replenished through natural processes.
- Reliable: This project diversifies the city’s water supply portfolio, which will reduce our dependence on a single source, thus making us less vulnerable to disrupted services.
- Responsible: This project will coordinate closely with the SFPUC’s Westside Basin Groundwater Monitoring Program, a robust monitoring network, to make sure that we operate in a responsible and sustainable manner so that this groundwater basin will be available for generations to come.
Groundwater will be blended together with the Hetch Hetchy supply at the Sunset and Sutro reservoirs and then be distributed throughout the city, as indicated by the blue shaded area. In a drought, the groundwater blend will be distributed throughout the entire City.
Bringing Groundwater to San Francisco
The San Francisco Groundwater Supply Project will provide the city up to 4 million gallons of local, sustainable groundwater every day. Compared to the entire city’s demand of 73 million gallons, the amount of groundwater that can be produced by this project is relatively small, but it is nevertheless a much needed addition to serve the City’s water needs and will assist us in prolonging our supply.
The San Francisco Groundwater Supply Project proposes to utilize up to six deep water wells and associated treatment facilities in the city. The project will be implemented in two phases:
Phase I: Install four new wells near West Sunset Playground, South Sunset Playground, Lake Merced Pump Station and Golden Gate Park. These wells would be able to provide a total of about 2.8 million gallons of water per day (mgd). The well stations would include a building to house the well pump and electrical, testing and treatment equipment.
Phase II: Convert two of the existing irrigation wells in Golden Gate Park to drinking water facilities, which would be able to provide another 1.2 mgd of supply to the city.
More than Just a Well! The West Sunset Well Facility’s design includes features that will allow it to serve as an emergency drinking water supply. It can be connected to a generator for backup power, provide on-site disinfection, and be connected to a dedicated hydrant for filling water tanker trucks.
Our Commitment to Providing High Quality Water
All blended water will be tested to ensure it exceeds all State and Federal drinking water regulations. We test our water daily and conduct over 30,000 tests every year. Groundwater will be included in this testing program when the San Francisco Groundwater Supply Project is implemented.