
After that, San Diegans made a collective vow: Never again.
In 1996, the San Diego County Water Authority struck a landmark agreement to buy water from farmers in the Imperial Valley, in California’s southeastern corner, that heralded the beginning of the region’s water divorce from Los Angeles.
Over the following two decades, the agency took on a series of significant — and expensive — infrastructure projects aimed at establishing more diverse sources of water, more places to keep it and more ways to move it around the county.
In 2010, the authority lined canals in the Imperial Valley with concrete to prevent water from seeping into the earth, and made a deal to take the water saved by the process — some 26 billion gallons a year. The authority finished raising the San Vicente Dam in 2014, adding more capacity to San Vicente Reservoir in the biggest water storage increase in the county’s history.
Then there was the long, fraught gestation of a seawater desalination plant, the largest in the United States and now the envy of desperate communities up the coast, in spite of environmental concerns. Since 2015, millions of gallons of seawater have flowed into the $1 billion facility in Carlsbad each day, where it is filtered into something that tastes like it came from an Evian bottle, not the Pacific Ocean.
Across the county, restrictions and conservation pushes have led per capita water use to fall by half over the past three decades.
The next major task? Expand the region’s so-called pure water programs, once given the derisive moniker “toilet to tap,” because they purify gray water to make it drinkable. Today, such programs are seen as some of the most promising paths forward, not just in San Diego but across the state. (The system in neighboring Orange County is often cited as a gold standard.)
San Diego has provided a road map for others now scrambling for water, said Toni Atkins, who is the president pro tem of the California Senate and previously served on the San Diego City Council. And she is proud of that.