FIGURE 26.1 Distribution of water on Earth. Fresh water represents less than 3 percent of all water on Earth, and only about three-fourths of that fresh water is surface water. Most of that surface water is frozen as ice and in glaciers. Therefore, less than 1 percent of all water on the planet is accessible for use by humans.

(Data from R. W. Christopherson, Geosystems, 7th ed. Pearson/Prentice Hall, 2009.)