Groundwater is water that is found underground in the cracks and spaces in soil and rock. Water is stored within an underground body of rock and can be retrieved for human use. There is a finite supply of water on the Earth, but it is continually recycled naturally.
Groundwater is the source of 50% of the drinking water in the US and is used at a rate of 90 billion gallons per day.
Most of the crops in the US are irrigated with groundwater.