Yeah, it's not a good look, especially since California is the only state that is adjacent to the ocean. Not only that, renewables like solar are perfect for desalination as you don't really need one of these systems to be running around the clock.
That's interesting, I had no idea.
https://en.wikipedia.org/wiki/Colorado_River_Compact
Places like Hawaii and Florida are, for obvious reasons, not relevant to the Colorado River.
If you have the real estate you can also go with evaporation ponds. Probably not too viable in California but it could be done in Texas.