Water is important because it is needed for life to exist. Many uses of water include agricultural, industrial, household, recreational and environmental activities, virtually all of these human uses require fresh water. Only 2.55 of water on the earth is fresh water, and over two thirds of this is frozen in glaciers and polar ice caps.
Fresh water is any naturally occurring water except sea water and salt water. Fresh water includes water in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers, streams and even underground water called ground water. Fresh water is generally characterized by having low concentration of dissolved salt and other total dissolved solids. Though the terms specifically excludes sea water and salt water.
Fresh water is not the same as potable water (Drinking water) much of the earth's water (on the surface and ground water) is unsuitable for drinking without some treatment. Fresh water can easily become polluted by human activities or due to naturally occurring processes, such as erosion.