Principal aquifers of California

Principal aquifers of California are those principal aquifers of the United States that lie within (or rather, below) the California state boundaries. Per the Oxford Dictionary of Environment and Conservation, an aquifer is a "body of permeable and/or porous rock that is underlain by impermeable rock and through which groundwater is able to flow." The state of California recognizes 515 groundwater basins and subbasins within these aquifers.

Source: Wikipedia — Principal aquifers of California (CC BY-SA 4.0)