groundwater: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Last updated

Oct. 26, 2026

News •

Surprising new pattern of groundwater loss may signal a turning point for the Colorado River Basin • Oct. 22, 2026, 5:18 AM ET (Live Science)

Facts

Also Known As	subsurface water

Photos and Videos

A cross-sectional diagram of land shows the water table as the upper boundary of groundwater, with a stream and pond representing surface water where the water table meets the land surface. Unsaturated soil lies above the water table.

A cross-sectional diagram showing how a geyser and hot spring form above a magma chamber. Arrows illustrate heat rising from magma, groundwater moving through porous rock, and steam or hot water reaching the surface as a geyser or hot spring. Labels identify each layer and process.

Diagram showing three stages of saltwater intrusion into a coastal aquifer: the first panel shows normal conditions with a stable interface between ocean saltwater and fresh groundwater; the second shows increased saltwater intrusion and a cone of depression when groundwater is pumped; the third shows how an injection well restores pressure and blocks saltwater intrusion. Labels identify ocean, aquifer, potentiometric surface, and water flow directions.

Searching for sustainable water supplies in Namibia

How stalactites and stalagmites form in caves

Can reed beds clean contaminated groundwater?

See All Videos and Images →

Topics

groundwater flow phreatic zone groundwater recharge artesian flow cryoseism vadose zone water table capillary fringe vadose water artesian well mineral water Why Is There Fresh and Salt Water on Earth?

Dig Deeper: More Articles That Discuss This Topic

water glass on white background. (drink; clear; clean water; liquid)

Water and its Varying Forms

Cave pool thermal spring in Grjotagja Cave, near Myvatn lake in Iceland. Groundwater. Lava cave

Groundwater Quiz