The government was/is the problem from the get go, mismanage by transferring water from one aquifer to one that didn't need it screwing the folks in the north (most recent). My wife professor out of Berkeley told her in the late 80s that the government was warned in California that the state can not sustain the level of growth and agriculture with the current water levels and that it would be a mistake to rely on the Colorado River because of growth in those regions the river feeds in the states the river runs through, it was also warned California will have to make a choice between developed communities and agriculture. The State didn't listen. I guess finger pointing doesn't help now and as @
Roninsensei said above private wells being capped.
California been wanting to tap the Columbia River here since the early 90s both Washington and Oregon told em to get screwed (they really wasn't that blunt) California knew then they was going to have problems and did nothing!