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All of Hillsborough’s water is provided by the San Francisco Public Utilities Commission (SFPUC).The SFPUC water supply comes from three major sources: Hetch Hetchy Reservoir in the Sierra Nevada Mountains, and the local watersheds in Alameda County and the Peninsula.Some customers occasionally notice slight changes in the flavor and hardness of their water as the ratio of waters from these sources changes according to seasonal and climate changes throughout the year.These changes are normal and pose no adverse health effects.

The Hetch Hetchy Reservoir, the largest reservoir in the SFPUC system, is located in Yosemite National Park.It provides approximately 85% of the total water supply.This high quality water supply meets all Federal and State criteria for watershed protection, disinfection treatment, bacteriological quality and operational standards.As a result, the EPA and California Department of Health Services granted the Hetch Hetchy water source a filtration exemption.This exemption is contingent upon the Hetch Hetchy source continuing to meet all filtration avoidance criteria.

Above: The Hetch Hetchy reservoir near Yosemite

Alameda County
and Peninsula watersheds produce about 15% of the total SFPUC water supply.The Alameda watershed, located in Alameda and Santa Clara Counties, collects local runoff and stores the water at Calaveras and San Antonio reservoirs, supplemented by groundwater from Sunol Filter Galleries.All water from these sources is treated at the Sunol Valley Water Treatment Plant located in the East Bay.Runoff captured in the Peninsula watershed in San Mateo County is stored in four reservoirs located just to the west of Interstate 280.This water source is treated at the nearby Harry Tracy Water Treatment Plant.

The SFPUC aggressively protects the natural water resources entrusted to its care by continuously monitoring its watersheds' weather conditions, water turbidity levels, and microbial contaminants.The annual update of the Watershed Control Program and Sanitary Survey describes the Hetch Hetchy watershed and water supply system, identifies potential sources of contamination in the watershed, discusses the existing and recommended watershed management practices that protect water quality, and summarizes the water quality monitoring conducted last year.The SFPUC also conducts a sanitary survey of local watersheds every five years. These surveys have consistently found very low levels of contaminants, and water from this the Hetch Hetchy Reservoir continues to remain safe and clean.
The Town of Hillsborough is also a member of the Bay Area Water Supply and Conservation Agency (BAWSCA). BAWSCA is working with the San Francisco Public Utilities Commission to implement the $2.9 billion capital improvement program. In particular, BAWSCA wants to ensure the aging water system is fixed and upgraded to withstand the seismic events expected to occur on the earthquake faults that cross under the system. The UWMP Act contained in California Water Code (“CWC”), Division 6, Part 2.6, Section 10610 requires that UWMPs be prepared every five years by urban water suppliers with 3,000 or more service connections, or that supply 3,000 or more acre-feet per year (“AFY”) of water. The Town owns and operates a water utility that serves nearly 11,000 people and supplied approximately 3,364 acre feet in fiscal year (“FY”) 2009/10; therefore, the Town must prepare an UWMP. The UWMP Act requires the Town to report, describe, and evaluate:

- Water deliveries and uses;
- Water supply sources;
- Efficient water uses; and
- Demand Management Measures (DMM) including implementation strategy & schedule

Click here to view the Town's 2010 UWMP

Links to Additional Resources
If you want to learn more about the SFPUC and our water system, visit:
For more information about the Hetch Hetchy system, visit
Take a virtual tour of the Hetch Hetchy Watershed here!
Hike along the Hetch Hetchy Reservoir in Yosemite:

The Town of Hillsborough 1600 Floribunda Avenue, Hillsborough, CA 94010 (650) 375-7400
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