Where is Earth's water located?

Yep, the Earth is doing a balancing act with its water! Water is continually moving around, through, and above the Earth as water vapor, liquid water, and ice. In fact, water is continually changing its form. The Earth is pretty much a "closed system," like a terrarium. That means that the Earth neither, as a whole, gains nor loses much matter, including water. Although some matter, such as meteors from outer space, are captured by Earth, very little of Earth's substances escape into outer space. This is certainly true about water. This means that the same water that existed on Earth millions of years ago is still here. Thanks to the water cycle (view a graphic of the water cycle), the same water is continually being recycled all around the globe. It is entirely possible that the water you drank for lunch was once used by Mama Alosaurus to give her baby a bath. By the way, there is a theory that much of Earth's water came from comets hitting the planet over billions of years.

How much of Earth's water is available for our uses ... and in what forms does it exist? You can best see how water is distributed by viewing these pie charts:

These bar charts also explain the data. The left-side pie chart shows that over 99 percent of all water (oceans, seas, ice, and atmosphere) is not available for our uses. And even of the remaining 0.3 percent (the small brown slice in the top pie chart), much of that is out of reach. Considering that most of the water we use in everyday life comes from rivers (the small yellow slice in the right-side pie chart), you'll see we generally only make use of a tiny portion of the available water supplies. The right-side pie shows that the vast majority of the fresh water available for our uses is stored in the ground (the large brown slice in the second pie chart). It might be easier to look at these numbers in the following data table. Notice how of the world's total water supply of about 326 million cubic miles of water, surface-water sources (such as rivers) only constitute about 300 cubic miles (about 1/10,000 th of one percent), yet rivers are the source of most of the water we use.

Water source	Water volume, in cubic miles	Percent of total water
Oceans	317,000,000	97.24%
Icecaps, Glaciers	7,000,000	2.14%
Ground water	2,000,000	0.61%
Fresh-water lakes	30,000	0.009%
Inland seas	25,000	0.008%
Soil moisture	16,000	0.005%
Atmosphere	3,100	0.001%
Rivers	300	0.0001%
Total water volume	326,000,000	100%

Source: Nace, U.S. Geological Survey, 1967 and
The Hydrologic Cycle (Pamphlet), U.S. Geological Survey, 1984

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How much water is there on Earth? Earth's water distribution
The water cycle and water cycle graphic (various languages)

Earth's water Water Science home page USGS Water Resources The URL for this page is http://ga.water.usgs.gov/edu/earthwherewater.html Comments? Contact Howard Perlman Last Modified: Aug 22, 2003