We’re at the end of a very long pipeline

The semi-arid San Diego region has very little natural resources; 1946 was the last year the region had sufficient local supplies to meet demand. The San Diego County Water Authority has imported water to meet the San Diego region’s needs through times of drought, economic expansion, and population growth.

The county has relied on Colorado River water since 1946 largely through the water it purchases from the Metropolitan Water District of Southern California. Through the historic Quantification Settlement Agreement of 2003, the San Diego region secured its own independent conserved Colorado River supplies.

These supplies consist of 200,000 acre-feet annually through the conserved water transfer agreement with the Imperial Irrigation District and 77,700 acre-feet conserved by concrete lining long stretches of the All-American and Coachella canals. These conserved QSA supplies are tied to senior priority water rights on the Colorado River and represent more than half of the San Diego region’s water and help to support a diversified, reliable supply portfolio.

The county also receives imported water from the Sacramento-San Joaquin Bay-Delta via the State Water Project to a limited extent. Depending on hydrologic conditions, the county has the flexibility to take zero supply from the Bay-Delta. Water from the Bay-Delta continues to be an important water resource and the region continues to do its part by reducing its reliance consistent with state law.

Imported Water Sources

colorado river aerial view
Colorado River

The Water Authority joined the Metropolitan Water District of Southern California (MWD) in late 1946, gaining access to Colorado River water. Water from the river reached San Vicente Reservoir in Lakeside a year later, via San Diego Pipeline 1 and MWD’s Colorado River Aqueduct (CRA).

northern califoria water source
State Water Project

Water from Northern California comes via the State Water Project and MWD. The Sacramento-San Joaquin Bay-Delta is the hub of the State Water Project. Efforts have been made in recent years to address the Bay-Delta’s complex environmental and water supply challenges.