GCSD obtains all of its water from the San Francisco Public Utilities Commission’s Hetch Hetchy Reservoir. This pristine water originates in Yosemite National Park as snow melt from a large watershed in the High Sierra. With controlled human contact and granite-type geology, the mineral content of this water is far lower than most bottled water, and the bacterial counts approach zero.
GCSD's Water System distributes water to the populated areas of Big Oak Flat, Groveland, and Pine Mountain Lake. The GCSD water supply and distribution system includes 3 water treatment plants, 5 storage reservoirs, and approximately 70 miles of distribution piping. The District provides a treated water supply to approximately 3,500 customers.