Over 70% of the Earth’s surface is covered in water.

But of that water, just 1% is readily available for human use, and of that 1%, 99% of it is stored beneath our feet as groundwater.

We all rely on groundwater in some way, so it’s important that we understand this vital resource.

What is groundwater?

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.

Groundwater is used for drinking water by more than 50 percent of the people in the United States, including almost everyone who lives in rural areas. The largest use for groundwater is to irrigate crops.

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Hydrologic Cycle

The Hydrologic Cycle

Water is always on the move.

Since the earth was formed, it has been endlessly circulating through the hydrologic cycle.

Groundwater is an important part of this continuous cycle as water evaporates, forms clouds, and returns to earth as precipitation.

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Groundwater from A-Z.

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What is a well?

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Learn how crops are irrigated.

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Threats to Groundwater

We rely on groundwater – it’s the water we drink, the water that grows our food, the water that helps recharge our lakes and rivers.

While some groundwater contaminants are naturally occurring, unfortunately, the majority of groundwater contamination is the result of human activity.

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