A natural underground layer, often of sand or gravel, that contains water.
Ground Water
The water that systems pump and treat from aquifers (natural reservoirs below the earth’s surface).
Raw Water
Water in its natural state, ground water or surface water, prior to any treatment for drinking.
Sole Source Aquifer
An aquifer that supplies fifty percent or more of the drinking water of an area.
Source Water
Water in its natural state, prior to any treatment for drinking. See finished water.
Surface Water
The water that systems pump and treat from sources open to the atmosphere, such as rivers, lakes, and reservoirs.
Water Shed
The land area from which water drains into a stream, river, or reservoir.