SAN DIEGO -- With a Carlsbad desalination plant set to start producing 50 million gallons of drinking water daily starting in 2012, San Diego County is positioned to become a global leader in making ocean water drinkable.

If all goes as planned, about 20 percent of all drinking water in the region will come from the ocean by 2020, The San Diego Union-Tribune reported.

Work is continuing apace on the Poseidon Resources plant in Carlsbad, and the San Diego County Water Authority recently completed a feasibility study on desalination plant at Camp Pendleton that would produce about 150 million gallons per day. The cost -- about $2 billion.

"If they go ahead with (the full-sized version), it will be the biggest seawater desalination plant in the world," Tom Pankratz, editor of the Water Desalination Report, told the newspaper.

Algeria is working to complete what would be the largest desalination plant in the world. Set to start operating in 2011, it would produce 132 million gallons per day.

The county water authority is also exploring with the International Boundary and Water Commission the idea of building a desalination plant in Rosarito Beach.

Pankratz said the desalination business was born in San Diego County.

In 1969, the first such plant to successfully demonstrate the reverse-osmosis process was installed at the Stardust golf course in Mission Valley, which is now called Riverwalk Golf Course. Water is forced at high pressure through a filter that removes impurities.

Membranes used for filtering are made by Hydranautics in Oceanside, Toray in Poway and Koch Membrane Systems in San Diego.

Desalination-related chemical companies include Professional Water Technologies in Vista, King Lee Technologies in San Diego and Avista Technologies in San Marcos.

Desalination is a logical step for the San Diego area because of its geographic constraints, said Ken Weinberg, the county water authority's director of water resources.

"The fact that there's no large groundwater basin limits our opportunities," he told the Union-Tribune. "We have very limited sources -- you have recycling, you have conservation and you've got the ocean."

The Oceanside and the Sweetwater water authorities in the South Bay have been desalinating brackish groundwater for years. Oceanside's 2 million- gallon-a-day output is expected to triple to 6 million gallons on Tuesday.

Sweetwater desalinates 3.8 million gallons a day and has teamed up with the Otay Water District to explore boosting that amount.

The city of San Diego is considering desalination of groundwater wells in places such as the San Pasqual and San Diego River valleys.

The county water authority projects that at least 89,600 acre-feet of the region's supply will come from the ocean by 2020.