California's water shortage

The recent report that California has just one year's worth of water left has made the rounds. Alex Tabarrok has a good primer or overview on the situation.

California has plenty of water…just not enough to satisfy every possible use of water that people can imagine when the price is close to zero. As David Zetland points out in an excellent interview with Russ Roberts, people in San Diego county use around 150 gallons of water a day. Meanwhile in Sydney Australia, with a roughly comparable climate and standard of living, people use about half that amount. Trust me, no one in Sydney is going thirsty.
 
So how much are people in San Diego paying for their daily use of 150 gallons of water? About 78 cents. As Matt Kahn puts it:
 
Where in the Constitution does it say that the people of California have the right to pay .5 cents per gallon of water?
 
Water is such a small share of most people’s budgets that it could double in price and the effect on income would still be low. Moreover, we don’t even have to increase the price of water for residential or industrial uses. As The Economist points out:
 
Agriculture accounts for 80% of water consumption in California, for example, but only 2% of economic activity.
 
What that means is that if agriculture used 12.5% less water we could increase the amount available for every residential and industrial use by 50%–grow those lawns, fill those swimming pools, manufacture those chips!–and the cost would be minimal even if we simply shut down 12.5% of all farms.
 

Water should cost more, and a few farms should shut down. Sounds sensible.