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The USGS Water Science School

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How much water is there on, in, and above the Earth?

Fresh groundwater and surface-water make up the bubble over Kentucky, which is about 252 miles in diameter. The sphere over Georgia reresents fresh-water lakes and rivers (about 34.9 miles in diameter).

All Earth's water, liquid fresh water, and water in lakes and rivers

Spheres showing:
(1) All water (sphere over western U.S., 860 miles in diameter)
(2) Fresh liquid water in the ground, lakes, swamps, and rivers (sphere over Kentucky, 169.5 miles in diameter), and
(3) Fresh-water lakes and rivers (sphere over Georgia, 34.9 miles in diameter).
Credit: Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.
View the picture full size. View full size

As you know, the Earth is a watery place. But just how much water exists on, in, and above our planet? About 71 percent of the Earth's surface is water-covered, and the oceans hold about 96.5 percent of all Earth's water. But water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.

Water is never sitting still, though, and thanks to the water cycle, our planet's water supply is constantly moving from one place to another and from one form to another. Things would get pretty stale without the water cycle!

All Earth's water in a bubble

This drawing shows various blue spheres representing relative amounts of Earth's water in comparison to the size of the Earth. Are you surprised that these water spheres look so small? They are only small in relation to the size of the Earth. This image attempts to show three dimensions, so each sphere represents "volume." The volume of the largest sphere, representing all water on, in, and above the Earth, would be about 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)), and be about 860 miles (about 1,385 kilometers) in diameter.

The smaller sphere over Kentucky represents Earth's liquid fresh water in groundwater, swamp water, rivers, and lakes. The volume of this sphere would be about 2,551,000 mi3 (10,633,450 km3) and form a sphere about 169.5 miles (272.8 kilometers) in diameter. Yes, all of this water is fresh water, which we all need every day, but much of it is deep in the ground, unavailable to humans.

Do you notice that "tiny" bubble over Atlanta, Georgia? That one represents fresh water in all the lakes and rivers on the planet, and most of the water people and life of earth need every day comes from these surface-water sources. The volume of this sphere is about 22,339 mi3 (93,113 km3). The diameter of this sphere is about 34.9 miles (56.2 kilometers). Yes, Lake Michigan looks way bigger than this sphere, but you have to try to imagine a bubble almost 35 miles high—whereas the average depth of Lake Michigan is less than 300 feet (91 meters).

Water is on and in the Earth

Picture of water flowing out of the ground.The vast majority of water on the Earth's surface, over 96 percent, is saline water in the oceans. The freshwater resources, such as water falling from the skies and moving into streams, rivers, lakes, and groundwater, provide people with the water they need every day to live. Water sitting on the surface of the Earth is easy to visualize, and your view of the water cycle might be that rainfall fills up the rivers and lakes. But, the unseen water below our feet is critically important to life, also. How would you account for the flow in rivers after weeks without rain? In fact, how would you account for the water flowing down this driveway on a day when it didn't rain? The answer is that there is more to our water supply than just surface water, there is also plenty of water beneath our feet.

Even though you may only notice water on the Earth's surface, there is much more freshwater stored in the ground than there is in liquid form on the surface. In fact, some of the water you see flowing in rivers comes from seepage of groundwater into river beds. Water from precipitation continually seeps into the ground to recharge the aquifers, while at the same time water in the ground continually recharges rivers through seepage.

Pie chart showing surface- and ground-water withdrawals in the U.S. in year 2005.

Humans are happy this happens because people make use of both kinds of water. In the United States in 2005, we used about 328 billion gallons per day of surface water and about 82.6 billion gallons per day of groundwater. Although surface water is used more to supply drinking water and to irrigate crops, groundwater is vital in that it not only helps to keep rivers and lakes full, it also provides water for people in places where visible water is scarce, such as in the desert towns of the western United States. Without groundwater, people would be sand-surfing in Palm Springs, California instead of playing golf.


Just how much water is there on (and in) the Earth? Here are some numbers you can think about:

Where is Earth's water located?

For a detailed explanation of where Earth's water is, look at the data table below. Notice how of the world's total water supply of about 332.5 million mi3 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. Rivers are the source of most of the fresh surface water people use, but they only constitute about 300 mi3 (1,250 km3), about 1/10,000th of one percent of total water.
Note: Percentages may not sum to 100 percent due to rounding.

One estimate of global water distribution
(Percents are rounded, so will not add to 100)
Water sourceWater volume, in cubic milesWater volume, in cubic kilometersPercent of
freshwater
Percent of
total water
Oceans, Seas, & Bays321,000,0001,338,000,000--96.54
Ice caps, Glaciers, & Permanent Snow5,773,00024,064,00068.71.74
Groundwater5,614,00023,400,000--1.69
    Fresh2,526,00010,530,00030.1  0.76
    Saline3,088,00012,870,000--  0.93
Soil Moisture3,95916,5000.050.001
Ground Ice & Permafrost71,970300,0000.860.022
Lakes42,320176,400--0.013
    Fresh21,83091,0000.260.007
    Saline20,49085,400--0.006
Atmosphere3,09512,9000.040.001
Swamp Water2,75211,4700.030.0008
Rivers5092,1200.0060.0002
Biological Water2691,1200.0030.0001
Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).

Sources and more information

Related topics:

Where is Earth's water?   The water cycle

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Page Last Modified: Wednesday, 19-Mar-2014 07:31:09 EDT