You know that in Southern California every single solitary source of ground or surface water has assigned to it a "water right" which is owned by somebody.
I believe that's the case in Northern California as well, but you can still put down a well on your own land by paying a small fee to the owner of the water rights.
In SoCal, where you have the Northern Neck of the world's most ancient desert, El Gran Sonora, you get water from a pipe or you don't get water ~ can't even find it anywhere ~
Not so. There are plenty of groundwater basins in Southern California. City of San Bernardino has so much groundwater that it wants to create man made lakes with houses around them and sell the surplus water. The San Gabriel Valley Water District could clean up some of its polluted water and be totally self sufficient for water (no imported water from Colorado River Aqueduct or California Aqueduct).