The majority of the District water supply is from the Cachuma Project, which the United States Bureau of Reclamation constructed on the Santa Ynez River in the early 1950s. Lake Cachuma provides about 85 percent of the water for the 250,000 residents and 12,000 acres of agriculture along the South Coast of Santa Barbara County. Supplies from Cachuma are also released for downstream water rights and federal fish protection requirements. The District is entitled to 36 percent, or 9,322 AFY, of the Lake yield, which provides for approximately two-thirds of District customer demand in normal years.
Cachuma supplies are delivered to the Goleta Valley through the Tecolote Tunnel and the South Coast Conduit and treated at the District Corona Del Mar Water Treatment Plant. Using Cachuma supplies to meet the majority of District demand keeps customer costs low as Cachuma is the most inexpensive source of water available to the District.
The Cachuma Project consists of Bradbury Dam, Tecolote Tunnel, South Coast Conduit, and various water conveyance facilities.