The drought could get much worse than disrupting home irrigation. Depending on how bad it gets, the price of water could rise and force people out, leaving them with no choice but to leave. I don't know what that would look like or how it would affect households already economically strained with limited capacity to move, but I doubt it will be a good situation.

The disruption to California's ability to produce food will also affect people outside of the state, raising prices.

There's probably water around to import if the price is right if it came to that, so I think it just becomes a question of market forces and how the drought will impact California's economy and the country. I don't think many people are going to die of thirst, although that is a real possibility for immigrants who cross the border illegally who may encounter less water because of the drought.