Parched California Pours Mega-Millions Into Desalination

Besieged by drought and desperate for new sources of water, California towns are ramping up plans to convert salty ocean water into drinking water to quench their long-term thirst. The plants that carry out the high-tech “desalination” process can cost hundreds of millions of dollars, but there may be few other choices for the parched state.

Where the Pacific Ocean spills into the Agua Hedionda Lagoon in Carlsbad, Calif., construction is 25 percent complete on a $1 billion project to wring 50 million gallons of freshwater a day from the sea and pour it into a water system that serves 3.1 million people.

Desalination was a dreamy fiction during the California Water Wars of the early 20th century that inspired the classic 1974 movie “Chinatown.” In the 1980s, however, the process of forcing seawater through reverse osmosis membranes to filter out salt and other impurities became a reliable, even essential, tool in regions of the world desperate for water.