Carlsbad Desalination Project 65 Percent Complete

October 01, 2014

At the start of the 2015 “water year,” the largest seawater desalination project in the Western Hemisphere is 65 percent…

At the start of the 2015 “water year,” the largest seawater desalination project in the Western Hemisphere is 65 percent complete and on schedule for delivering drought-proof water supplies to the San Diego County Water Authority next fall.

The $1 billion project will produce 50 million gallons of water a day for use across the San Diego region, providing a major resource that will meet about 7 percent of the county’s need for water in 2020 and account for about one-third of all locally generated water. This new water supply and its cost will be combined with the Water Authority’s other supplies serving 24 local water agencies, 3.2 million people and a $206 billion economy.

“We couldn’t be more pleased with the progress on this world-class project, and we are eager to show the world what it can do,” said Peter MacLaggan, Vice President of Poseidon Water, the project’s private developer. “Our contractors and our host communities of Carlsbad, San Marcos and Vista have set a new standard for cooperation and efficiency, and that has allowed us to make fantastic progress during nearly two years of construction.”

The first day of October begins the “water year” for resource managers – the start of the season when snow and rain collects for use the following calendar year. After three dry winters, the next several months are pivotal for California; below-average precipitation could lead to more mandatory water-use restrictions statewide. The Water Authority’s Board declared a Drought Watch condition in February to encourage increased voluntary water conservation. In July, the Board moved to a Drought Alert condition, making Drought Watch conservation measures mandatory and adding outdoor watering restrictions. Local rules vary based on regulations adopted by the Water Authority’s member agencies. 

“As drought conditions deepen statewide, the value of the Carlsbad Desalination Project continues to grow for San Diego County,” said Mark Weston, Chair of the Water Authority’s Board of Directors. “But it’s important to remember that the purpose of the Carlsbad Desalination Project isn’t only to help during the current drought. It will be a core, high-quality water source for decades, and it is a key part of the Water Authority’s strategy to improve the reliability of our region’s water supply by diversifying our water resources.”

The desalination plant, which sits on about six acres of public utility zoned land next to the Encina Power Station and Agua Hedionda Lagoon, will produce up to 56,000 acre-feet of water annually – enough to serve approximately 112,000 typical homes. A 10-mile pipeline will connect the plant to the Water Authority’s regional delivery system. Approximately 7.25 miles – or 39,000 linear feet – of the large-diameter pipe has been installed through San Marcos, Vista and Carlsbad. In addition, the Water Authority is making about $80 million in upgrades to its facilities to accommodate the addition of desalinated seawater. These facilities include Pipeline 3 and the Twin Oaks Valley Water Treatment Plant near San Marcos, where desalinated water will be mixed with water from other sources.

The Water Authority signed a 30-year Water Purchase Agreement with Poseidon in 2012, launching construction of the Carlsbad project. During the three-year building process, the desalination project is supporting an estimated 2,500 jobs and infusing $350 million into the local economy.  A joint venture of Kiewit Infrastructure West and J.F. Shea Construction, Inc. is designing and building the desalination plant and pipeline. IDE Technologies, a world leader in desalination technology and operations, is engineering the plant’s desalination process and related equipment. IDE also will operate the plant.

The Carlsbad project was developed through a rigorous environmental permitting process. It will deliver several environmental benefits by adopting cutting-edge technology to recapture energy used in the desalination process, offsetting carbon emissions and developing extensive wetlands that will enhance fish populations along the San Diego County coastline.

When construction is complete, Poseidon will seek a drinking water permit for commercial operations from the State Water Resources Control Board and perform start-up testing for water delivery starting as soon as fall 2015.

For more information about the Carlsbad Desalination Project, visit the project website at, or the Water Authority’s website,

  • The San Diego County Water Authority sustains a $268 billion regional economy and the quality of life for 3.3 million residents through a multi-decade water supply diversification plan, major infrastructure investments and forward-thinking policies that promote fiscal and environmental responsibility. A public agency created in 1944, the Water Authority delivers wholesale water supplies to 23 retail water providers, including cities, special districts and a military base.

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