Its the energy cost of pumping the water to the surface that is prohibitive. This is actually a good use for a windmill (one of the original uses of a windmill), since the need to pump water isn’t instantaneous.
San Antonio gets the majority of its water from a series of submersible pumps in the Edwards Aquifer. Albeit, the wells are only around 500’ deep but it can be done. It is more of a cavernous limestone with infinite permeability. I am not sure what flow capacity the California aquifers have.