Mar 2, 2019 · Groundwater is the largest source of fresh water on Earth - it's kind of a big deal. The USGS monitors, tests, and studies groundwater resources to assure one of our Nation's …

Groundwater is an inevitable result of gravity: if surface water can seep into the ground before it evaporates or flows away, it will. Water also flows through rocks underground and may flow …

State of CaliforniaGroundwater is an important source of water stored in the earth, deep beneath our feet, in what are called aquifers. Aquifers are the collective saturated spaces between …

Jul 20, 2018 · State of CaliforniaHow do we get groundwater? Water in aquifers may be brought to the surface naturally through a spring, or can be discharged into lakes and streams. …

Groundwater is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers. …

Jun 16, 2025 · What is Groundwater? The Earth’s Hidden Reservoir Groundwater is water that exists beneath the Earth’s surface, filling the spaces between […]

Dec 1, 2025 · EPA's Office of Ground Water and Drinking Water

This page discusses groundwater as the largest freshwater reservoir found in aquifers. It explains the structure of aquifers, highlights key terms like water table and wells, and emphasizes the …

The global water crisis is in fact a groundwater crisis because groundwater makes up 99% of all liquid fresh water and in times of drought, groundwater is the only freshwater available in many …

Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 37 percent of the water that …

The USGS annually monitors groundwater levels in thousands of wells in the United States. Groundwater level data are collected and stored as either discrete field-water-level …

Groundwater ® is the leading international journal focused exclusively on groundwater. Since 1963, Groundwater has published a dynamic mix of papers on topics related to groundwater …

Water-use specialists at the U.S. Geological Survey report that about 341 billion gallons of fresh-water a day was used in the United States in 1995 for public supplies, rural domestic and …

Groundwater & Aquifers Groundwater is water that occurs in the subsurface. An aquifer is a geologic material (rocks and sediments) capable of delivering groundwater in usable …