Just checked and apparently we have 11 desalination plants operating in California, though Carlsbad is by far the biggest. Poseidon is opening a new bigger plant in Huntington Beach that will be the first to use carbon-neutral energy, and their Carlsbad plant is going to be going to that shortly. One of the biggest objections of anti-desal activists is their concentrated brine effluent causing environmental damage, so the Carlsbad plant draws in enough sea water to dilute their brine to 20% more salt rather than the usual 50%. Natural salinity varies from 28% to 37%, depending on latitude, so 20% enriched brine does not make much difference and dissipates quickly.
We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.