Any real water shortage would result in residential users who are a large majority of the population outbidding agricultural users. But we actually won’t have any water shortages, this is just Chicken Little propaganda by major water users eager for even more state subsidies.
In a free market for water, Western state residential water bills would decrease substantially. The “cost” would be, e.g., on Chinese consumers who wouldn’t get our almond exports quite so cheaply, and the ultrarich owners of farms that get water subsidies.
We have a real water shortage. California grows 50% of Americas fruit and veg. So what you are really stating is that in a free market, we’d all have plenty of residential water (more expensive than now but not horribly so) at the expense of fresh fruits and veg a lot of the year. That’s cutting off your nose to spite your face. Yes the Chinese should pay more for almonds, and agricultural water should be more expensive with the explicit social goal of moving us towards perma culture, but be careful what you wish for.
Josh