How San Diego secured its water supply, at a cost

Because a worsening drought is forcing millions of Californians to cope obligatory water restrictions, one corner of Southern California has largely shielded itself from supply-related problems: San Diego County.

For western water planners, the path it took to get there serves either as a sketch or a warning story.

Over the past three decades, San Diego County has diversified its water supply, increased conservation and invested in large-scale water infrastructure including the largest desalination in the western hemisphere, which removes salt and impurities from ocean water. As a result, the water agency that serves 24 water services including the city of San Diego says it can avoid cuts by at least 2045, even during dry periods. But that security cost money.

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

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


San Diegans did not always rest quietly during drought. In the 1990s, a severe drought cut the region’s water supply by 30%. At the time, almost all of its water came from the Metropolitan Water District, the country’s largest water supplier. That experience and a tense, dysfunctional relationship – say California water experts – with water officials in Los Angeles spurred San Diego County’s aggressive, decades-long search for water self-sufficiency.

“At that point, our community came together and said,‘ We’re not going to be in this situation again. We have to plan for our own reliability, ”said Sandy Kerl, director general of the San Diego County Water Authority.

So in 2003, the water authority cut a deal to get water from Colorado’s only major user, the Imperial Irrigation District, in Southern California. San Diego County has financed repairs to leaked canals belonging to Imperial and signed a historic transfer agreement. Today, it receives about 55% of its total supply from Imperial as part of the deal.

The water authority also helped farmers use less water. It raised dams to increase storage capacity in reservoirs. It provided discounts to homeowners who uprooted grass lawns for water-efficient alternatives.

In 2012, San Diego County forged a deal to get 10% of its water supply from the Carlsbad Desalination Plant over the next 30 years. The plant produces 50 million gallons of potable water – enough for about 400,000 people – every day and is by far the region’s most expensive water source.

“In round terms, it’s twice as expensive as imported surface water,” Hanemann said. “On the other hand, it’s a very reliable supply because it’s not affected by drought and low currents in rivers in Northern California or Colorado.”

As these efforts took hold, demand steadily fell, even as half a million more people relocated to San Diego. Statewide water cuts during drought, more effective rains, toilets and faucets, discounts on weeding and the use of recycled water did what they were supposed to do – steeply. reducing per capita water use. By 2020, San Diegans used 30% less water than in 1990.

Water officials, however, did not anticipate the next drop in demand and constantly overestimated how much water was needed. Today, San Diego County says it is no longer looking for more water, a position that some in the West might find enviable. But they would not envy the water tariffs.

Thanks to selling less water, San Diego County has raised rates – an average of 4% for each of the past five years – to cover fixed costs including the San Vicente Dam and a desalination plant. Such costs make up the bulk – about 90% – of the agency’s annual expenses.

The price of water, Hanemann said, is largely determined by the infrastructure that moves and stores it. “You’re fished if you suddenly deliver fewer gallons of water because your costs don’t go down.”

“Water is a terrible business because we need to encourage people to use less of our product and charge them more when they do,” said Tom Kennedy, general manager of the Rainbow Municipal Water District, one of the two water agencies testing. detached from the San Diego County Water Authority.


Rainbow and Fallbrook, the other city whose agency is trying to source its water elsewhere, say doing so would give them access to cheaper water, although the potential savings are not yet known. A state agency is considering whether they can leave, with a decision expected before the end of the year. If their exit is approved, the next step would be a vote among residents. Only if that vote passes can the two districts leave.

At a recent public hearing, angry residents shouted at officials about how long the process takes – and how expensive their bills have become in the meantime.

The rural towns cut a striking contrast to the constellation of San Diego from beach towns and waterfront skyline. Northeast of the city, steep, dry hills and vast canyons dot the landscape.

Steep water costs have hurt farming in Fallbrook and Rainbow, once the largest producer of avocados in the country. Between 2016 and 2020, Fallbrook lost nearly a fifth of its avocado groves, government records show, due to urbanization and depleted groves.

Jason Kendall, a farmer in Rainbow whose family took out his avocado groves years ago, said growing the fruit without supplemental groundwater is a losing business.

“You just can’t make a profit by buying district water and cultivating avocados,” said Kendall, who owns 350 acres (142 acres) of cut flowers that are widely grown in the area.


Water officials in San Diego County say higher water costs are coming for other parts of California and the West, even though desalination is less popular today than it once was. Recently, California Coastal Commission neis a permit for Poseidon Water to build an additional decade-in-the-air desalination plant about 60 miles (97 kilometers) up the coast, in Huntington Beach. The rejection came after years of opposition from environmentalists.

The rest of the state has work to do, officials in San Diego County said, as climate change continues to intensify droughts and shrink the rivers feeding the California and Colorado reservoirs.

“There’s no cheaper water available,” Kerl said.


The Associated Press receives support from the Walton Family Foundation for water coverage and environmental policy. The AP is solely responsible for all content. For full AP environmental coverage, visit

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