Drinking water comes from surface water and ground water.
Large-scale water supply systems tend to rely on surface water resources that come from rivers, lakes, and reservoirs and the smaller water systems tend to use ground water coming in from wells that are geologically drilled into water bearing aquifers. Aquifers are geological formations that contain water. The quantity of in an aquifer and the water produced by the well depend on the nature of the rock, sand, or soil where the well withdraws water. Drinking water wells may be as shallow as 50 feet or less to more than a 1,000 feet. Your water utility or public works department can tell you the source of your supply.