Water Distribution
What is the big deal?

Water on and in the Earth

Where is Earth's water located and in what forms does it exist? You can see how water is distributed by viewing these pie charts. The left-side pie shows where the water on Earth exists; about 97 percent of all water is in the oceans. The middle pie shows the distribution of that three percent of all Earth's water that is freshwater. The majority, about 69 percent, is locked up in glaciers and icecaps, mainly in Greenland and Antarctica. You might be surprised that of the remaining freshwater, almost all of it is below your feet, as ground water. No matter where on Earth you are standing, chances are that, at some depth, the ground below you is saturated with water. Of all the freshwater on Earth, only about 0.3 percent is contained in rivers and lakes—yet rivers and lakes are not only the water we are most familiar with, it is also where most of the water we use in our everyday lives exists.

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. The right-side pie chart shows that over 99 percent of all water (oceans, seas, ice, most saline water, and atmosphereic water) is not available for our uses. And even of the remaining fraction of one percent (the small blue 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 dark blue slice in the bottom 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 grey slice in the second pie chart).

Estimate of global water distribution
Total AreaWater source Volume in miles3
Volume in kilometers3
 % of Freshwater  % of Total Water
Oceans, Seas, & Bays  321,000,000 1,338,000,000  –  96.5
Ice caps, Glaciers, & Permanent Snow 5,773,000 24,064,000 68.7  1.74
Groundwater 5,614,000 23,400,000 –   1.7
      Fresh 2,526,000  10,530,000 30.1  0.76 
      Saline 3,088,000 12,870,000 –  0.94 
Soil Moisture 3,959 16,500 0.05  0.001 
Gound Ice and Permafrost 71,970 300,000 0.86  0.022 
Lakes 42,320 176,400 –  0.013 
       Fresh  21,830  91,000  0.26  0.007
       Saline  20,490  85,400  –  0.006
 Atmosphere  3,095  12,900  0.04  0.001
 Swamp Water  2,752  11,470  0.03  0.0008
 Rivers  509  2,120  0.006  0.0002
 Biological Water  269  1,120  0.003  0.0001
 Total  332,500,000  1,386,000,000  100

For a detailed explanation of where Earth's water is, look at this table. Notice how of the world's total water supply of about 332.5 million cubic miles (1,386 million cubic kilometers) of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Thus, surface-water sources (such as rivers) only constitute about 22,300 cubic miles (93,100 cubic kilometers), which is about 1/700th of one percent of total water, yet rivers are the source of most of the water people use.

Credit: U.S. Geological Survey Department of the Interior/USGS, Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp.817-823.

© 2024 SPC Water, Sanitation and Hygiene. All rights reserved.