Roughly 71 percent of the Earth is covered in water, according to the U.S. Geological Survey. However, 96.5 percent of the water covering the Earth is saltwater and is unsuitable for human consumption. The remaining 3.5 percent is composed of glacial frozen water, freshwater lakes and the polar ice caps.
Humans use less than 1 percent of the Earth's freshwater. Aside from the water covering the Earth, water is also found in air in the form of water vapor, in aquifers, in ground soil in the form of soil moisture and in living organisms. The water covering the Earth's surface plays a crucial role in weather and climate systems.