Local Supplies

The Water Authority’s local water management program focuses on the planning and development of local water resources. The majority of local sources are developed and managed by the Water Authority’s member agencies and are critical to securing a diverse and reliable supply for the region. Local projects reduce demand and reliance on imported supplies. This benefits the region by increasing the reliability and cost certainty of these supplies.


Before 1947, the San Diego region relied on local surface water runoff in normal and wet weather years and on groundwater pumped from local aquifers during dry years when stream flows were reduced. As the economy and population grew, local resources became insufficient to meet the region’s water supply needs. From the 1950s onward, the region became increasingly reliant on imported water supplies.  On average, about a third of all water used within San Diego County comes from local sources. The remaining water must be imported. The Water Authority is actively pursuing local supply and conservation projects that will increase local water use to approximately 40 percent of total supply by 2020.

Local water supply management includes the following: