FactSentinel

The claim confuses total water with fresh water. Oceans hold about 96.5 percent of all water on Earth, but that water is salty. By definition, fresh water has very low dissolved salt content, so seawater does not count toward the planet's fresh water supply. The oceans therefore contain essentially none of Earth's liquid fresh water, and the figure of more than 90 percent is wrong.

According to U.S. Geological Survey estimates, fresh water makes up only about 2.5 percent of Earth's water. Roughly two-thirds of that is locked in glaciers, ice caps, and permanent snow, so it is not liquid. Most of the liquid fresh water is groundwater stored in soil and rock. Lakes, rivers, wetlands, and soil moisture together make up a very small fraction, and rivers alone account for only a tiny sliver of the total.

The mistake likely comes from a true statistic: oceans contain over 90 percent of all water on the planet. Dropping the word "fresh" turns an accurate fact into a false one. A related misconception is that visible surface water, such as lakes and rivers, makes up most of the available fresh water. In reality, much more is hidden underground or frozen. Desalination can turn seawater into drinking water, but the ocean is still classified as saline, not fresh.