[daepp]

Not too many people; too little infrastructure expansion.

California's water system was built for 20 million people; the state now has 40 million. No new reservoirs since Diamond Valley (planned in the ate 50's; completed in the 90's).

Supreme Court decision a decade or so ago also allowed for more AZ agriculture east of the Colorado river.

Ps: 50% of CA fresh water flows unused to the sea, ostensibly to protect a couple of endangered fish. But some (all) of the smelts are now known to be non-native to CA - current theory is they came in the ballast of bulk carrier ships from China, who come here (often) empty of cargo but full of water ballast, drawn in from Asian waters...

And so it goes...