The California Coastal Commission is slated to vote Thursday on a crucial permit for a project that would draw ocean water through the sand off the coast of Dana Point, purify it and use it to help bolster water supplies for communities throughout Southern California.

A dozen desalination plants are permitted to turn ocean water into drinking water in California today, from as far south as Carlsbad to as far north as Monterey Bay. A year ago, three new desalination projects were pending in Southern California alone. But only one still remains viable: the Doheny Ocean Desalination Plant, which is being developed by South Coast Water District.