Locked deep within the lithosphere, or surface of the Earth, is found many billions of gallons of water. Almost anywhere on Earth, it is possible to dig down and find a supply of fresh drinkable water. Almost all of this water was deposited over millions of years by the many rain and snow storms that have visited the surface of the Earth.
Most ground water lies within ½ mile (0.8km) of the surface of the Earth. However, scientists have found water at a depth of more than six miles (10km).