Most of the water is used by agriculture. You can take all the 2 minute showers you want, changing how the megafarms use all that water would have the most impact.

Of course, there's this idea that the farms are the historical yeoman-type, so it's rare to see solutions involving agriculture dicussed.

http://californiawaterblog.com/2011/05/05/water%E2%80%94who-...

> When you examine water use within the interconnected network of California that feeds farms and cities, use is roughly 52 percent agricultural, 14 percent urban and 33 percent environmental.