The Water Table

Below the surface of the Earth, there is water hidden in the ground. The water table is the level where the soil and rock are completely filled with water. Above the water table, the ground has both air and water in its spaces. Below it, every space is filled with water.

How the Water Table Works

When it rains, water soaks into the ground and moves downward. It fills tiny spaces between grains of soil and cracks in rocks. At some depth, all the spaces are filled. That level is the water table. The water table can be just a few feet underground or hundreds of feet deep.

Why It Matters

The water table is important because many people get their drinking water from wells that reach down to it. When there is a lot of rain, the water table rises. During dry spells, it drops. If too many wells pump water faster than rain replaces it, the water table can drop very low.

Fun Facts

• About 30 percent of the world's fresh water is stored underground below the water table.
• In some desert areas, the water table is over 1,000 feet below the surface.
• When the water table meets the surface, it creates springs, lakes, and wetlands.

Did You Know?

The Ogallala Aquifer under the Great Plains of the United States holds enough water to fill Lake Huron. Farmers rely on it to water their crops, but it is being used faster than rain can refill it!