Officials move toward building desalination plant at Camp Pendleton

San Diego County water officials on Thursday announced they have taken a significant step toward the possible construction of the county’s second desalination plant — this one at Camp Pendleton.

An agreement has been reached between the Marine Corps and the San Diego County Water Authority to study how a plant could be built on the base.

As part of the agreement, the authority’s governing board authorized a $4.05-million contract to build a pilot project to test various methods of turning seawater into drinking water. The project is expected to take about two years.

Nothing in the agreement obligates either the Marine Corps or water authority to build a desalination project. And even if a decision were made later to build such a plant, officials predict it would not be completed until after 2030.

Getting the myriad permits needed, along with the construction phase, could take a decade or more, officials said.

Still, after off-and-on discussions since 2007, the pilot project will help both sides to “understand the most environmentally friendly and economically feasible” way to build a plant on base, said authority Chairman Mark Weston.

Two sites have been targeted for a possible large-scale plant, both near the 5 Freeway and the mouth of the Santa Margarita River. The goal would be to build a plant capable of producing 150-million gallons a day, officials said.

The $1-billion plant at Carlsbad — billed as the largest desalination project in the country — is set to begin providing potable water within weeks. Although no date has been announced, the contract calls for the plant to be operational by Thanksgiving.

The plant is expected to provide 7% to 10% of the region’s demand for water.

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