Water Science School
Groundwater
Groundwater is one of our most valuable resources—even though you probably never see it or even realize it is there. There is water somewhere beneath your feet no matter where on Earth you live. Groundwater starts as precipitation, just as surface water does, and once water penetrates the ground, it continues moving, sometimes quickly and sometimes very slowly. Eventually groundwater emerges back to the surface and continues to participate in the global water cycle.
Groundwater and the water cycle
Large amounts of water are stored in the ground. The water is still moving, possibly very slowly, and it is a part of the water cycle.
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Groundwater Information by Topic
Groundwater is one of our most valuable resources—even though you probably never see it or even realize it is there. There is water somewhere beneath your feet no matter where on Earth you live. Groundwater starts as precipitation, just as surface water does, and once water penetrates the ground, it continues moving, sometimes quickly and sometimes very slowly. Eventually groundwater emerges...
The Water Science School -- What We Offer
The U.S. Geological Survey's Water Science School
Where anyone of any age can learn all about water.
Water Science Photo Galleries
Learn about water using pictures
Water Q&A: Is measuring water in a well like measuring a stream?
Find out more about how the USGS measures groundwater levels.
Water Q&A: My mom drinks "artesian well water". What is it?
Find out more about artesian groundwater and confined aquifers under pressure.
Water Q&A: What makes a groundwater well go dry?
Learn about some of the things that can effect water levels in wells.
Water Q&A: How important is groundwater?
Learn how important groundwater is to some communities.
Water Q&A: Is groundwater always clean?
Learn about groundwater quality and potential contaminants.
Water Q&A: Why do water levels in wells rise and fall?
Water levels in groundwater wells can fluctuate due to changes in pumping, recharge (how fast the groundwater is replenished), and even the season.
Water Q&A: What water data does the USGS gather?
The USGS collects data about the country's water resources including the quantity and quality of water in our streams, rivers, groundwater, and more.
La Ciencia del Agua para Escuelas
La Ciencia del Agua para Escuelas
Groundwater Quality
Even though the ground is an excellent mechanism for filtering out particulate matter, such as leaves, soil, and bugs, dissolved chemicals and gases can still occur in large enough concentrations in groundwater to cause problems.
Base Flow in Rivers
When a drought hits and little or no rain has fallen in a long time, you might expect small streams and even larger rivers to just dry up, right? In many cases, they don't. Streamflow might lessen to a trickle or so, but water continues to flow. How is that possible? Read on to find out how "base flow", which is water seeping into the stream from groundwater, helps keep water in streams during...