Water Supplies

A safe, reliable water supply is crucial for the vitality of the San Diego region’s $245 billion economy and quality of life for 3.3 million residents. To maximize the reliability of those supplies, the Water Authority is executing a long-term strategy to diversify its water sources, make major investments in the region’s water delivery and storage system, and improve water use efficiency.


Supply Diversification

In 1991, the San Diego region was 95 percent reliant on a single supplier of imported water – the Metropolitan Water District of Southern California. This made the region extremely vulnerable to water supply shortages. That year, an ongoing drought forced MWD to cut deliveries to the San Diego region by 31 percent.

Regional Water Supply Portfolio Diversificationsupply diversification
Click image above to enlarge.

As a result of that crisis, the Water Authority Board of Directors approved a strategy to aggressively diversify the region's water supply portfolio by developing new local and imported water supplies. This strategy is significantly enhancing regional supply reliability. By fiscal year 2012, the San Diego region had reduced its reliance on MWD supplies to 45 percent. 

The Water Authority is working with its 24 local member retail agencies to develop local supplies such as groundwater, recycled water, seawater desalination, and conservation. By 2020, local water supplies are projected to meet more than a third of the region’s water demand.

The Water Authority also has secured new imported water supplies through a long-term (45 to 75 years) water conservation and transfer agreement with the Imperial Irrigation District. The deal, reached in 2003, provided 115,000 acre-feet of Colorado River water in 2018 and increases to 200,000 acre-feet annually by 2021.

The Water Authority also has a separate, 110-year agreement to receive Colorado River water conserved by lining parts of the Coachella and All-American canals. These projects provide 80,000 acre-feet of water to the region annually.

What is an Acre-Foot?

An acre-foot is 325,900 gallons – roughly enough to submerge an entire football field a foot deep. It's approximately the supply used by 2.5 single-family households of four for a year.

Improving Infrastructure

San Vicente Dam rendering
The San Vicente Dam Raise project will be completed by 2014.

The Water Authority also is in the final stages of executing a $3.1 billion Capital Improvement Program to further improve regional water delivery and storage capacity. The program includes dozens of projects, including new reservoirs, pipelines, pumping stations and a regional water treatment facility. Major projects include raising San Vicente Dam in East County by 117 feet to provide 157,000 acre-feet of additional local storage.



Promoting Conservation

Water-efficient landscapes help stretch the region's water supply.

In addition to developing new water supplies, the region uses water resources efficiently. That’s why water-use efficiency has been a key component of the Water Authority’s supply diversification strategy for the past two decades. The Water Authority works with its member agencies and other partners to offer programs that improve water-use efficiency for residential, commercial, and agricultural users and help promote conservation as a way of life in the San Diego region.

Conservation tips and program information is at WaterSmartSD.org.

Colorado River
The Water Authority imports more than 70 percent of the region's water supplies. The Colorado River is the source for most of San Diego County's imported water.

This Water Authority is cost-effectively managing the region's water supply portfolio through: