A lot of the coastal cities have storm drain systems that drain rainwater directly into the ocean instead of trying to capture and process it to make it safe for irrigation if not drinking. Which is a much easier problem than trying to desalinate ocean water.

It wouldn't be the solution to CA's water problem, but it's a lot of water that's currently going to waste. But I suspect there's less potential for grift doing that than there is in building desalination plants.