San Diego's Desalination Plant Could Ease Water Shortages

While cities across the Southwest brace for dramatic water cuts, San Diego County just found a way to help its neighbors and show a new path forward for managing America's most important river.

The San Diego County Water Authority voted unanimously last week to explore selling some of its water supplies to Arizona and Nevada. These states face severe shortages as the Colorado River, which serves 40 million people across seven states, continues to shrink from drought and climate change.

What makes this possible? The Claude "Bud" Lewis Carlsbad Desalination Plant has been converting ocean water into fresh drinking water since 2015. It's the nation's largest such facility, and right now it's only running at partial capacity because operating at full speed costs more than using other water sources.

But if Arizona and Nevada buy some of San Diego's Colorado River water, that revenue would make it worthwhile to ramp up the desalination plant. The ocean water would replace what San Diego sells, and the money earned would actually lower water bills for San Diego residents.

General Manager Dan Denham calls it "just a different way of managing water in the West." Starting next year, the authority could sell up to 10,000 acre-feet of water. That's enough to supply nearly 5% of Las Vegas's current needs. In future years, that number could grow to 25,000 acre-feet or more.

San Diego is in this enviable position because it invested heavily in water security. Beyond the desalination plant, the region locked in water through a 2003 agriculture-to-urban transfer deal. Conservation efforts have reduced demand across the county's 3.3 million residents. And new wastewater recycling facilities, including San Diego's Pure Water project, will add even more supply in coming years.

The deal still needs approval from several agencies, including the Metropolitan Water District of Southern California and the federal government. But support is building. Governor Gavin Newsom backed the concept in a recent letter, and the Trump administration's acting head of the Bureau of Reclamation has expressed support too.

The Ripple Effect

This interstate water trade could be just the beginning. If successful, it proves that states don't have to fight over dwindling river water when they can create new supplies from the ocean. The approach could inspire similar projects up and down the West Coast, where desalination plants sit near landlocked communities desperate for water.

Metropolitan Water District General Manager Shivaji Deshmukh captured the shift in thinking perfectly: "We need to think about water resources not from political boundaries, but as a region."

Yes, the amount San Diego can sell is small compared to the Colorado River's total shortfall. But sometimes the biggest changes start with one community showing what's possible.