We use many, many times more water to grow alfalfa that's exported to China than illegals consume. A quarter of the water use in California goes to just two crops, almonds and alfalfa, both of which are mainly exported overseas. Overall, 80% of water use goes to irrigation. Of what's left, most goes to landscape watering--golf courses a big chunk of it. Only about 8% of water use goes to household use--toilets, showers, etc.
While I feel for the farmers in California whose livihood depends on irrigation, but their farming lifespan was always limited to the fact they depend on irrigation.
Even with plentiful water supply the fact that ground water carries minerals(specifically salt) after a time, builds up in the soil and “poisons” it, choking off production.
Rain water doesn’t have this and thus any farm that uses irrigation as a main water source has a limited productivity span.
As for the rest of California, you can just hoist upon your own petard(you voted for these fools)