How San Diego secured its water supply, at a cost

As a worsening drought forces millions of Californians to face mandatory water restrictions, one corner of Southern California has largely shielded itself from supply-related woes: San Diego County.

For Western water planners, the path it took to get there serves either as a blueprint or a cautionary tale.

Over the past three decades, San Diego County diversified its water supply, ramped up conservation and invested in big-ticket water infrastructure including the Western hemisphere’s largest desalination plant, which removes salt and impurities from ocean water. As a result, the water agency that serves 24 water utilities including the city of San Diego says it can avoid cuts until at least 2045, even during dry periods. But that security has come at a cost.

San Diego County's water is among the most expensive in the country, costing about 26% more at the wholesale level in 2021 than the Metropolitan Water District's, which serves Los Angeles and surrounding counties. Now, two rural irrigation districts in San Diego County home to large avocado industries want to break away from the regional water supplier, saying they can purchase cheaper water elsewhere. If they succeed, water in San Diego County could grow even more expensive.

“San Diego's situation is very surprising, very striking,” said Michael Hanemann, an environmental economist at Arizona State University who recently was commissioned to study the region's water costs for a California agency. “I think this is a harbinger of something that’s going to happen elsewhere in California and elsewhere in the U.S.”

WHY SO EXPENSIVE

San Diegans didn't always rest easy during drought. In the 1990s, a severe dry period cut the region's water supply by 30%. At the time, almost all of its water came from the Metropolitan...