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 collected with wells and pumps, or it can flow naturally to the surface via seepage or springs. Groundwater can be thousands of years old, although typically it is extracted within years or decades after it originally moves underground through small openings within porous material, called aquifers.
Why is there groundwater? Nothing surprising here – gravity pulls water and everything else toward the center of the Earth. That means that water on the surface will try to seep into the ground below it. The rock below the Earth’s surface is the bedrock. Groundwater occurs in the saturated soil and rock below the water table. If the aquifer is shallow enough and permeable enough to allow water to move through it at a rapid-enough rate, then people can drill wells into it and withdraw water.
In other areas the water is polluted by human activities. There is no such thing as naturally pure water. … As water flows in streams, sits in lakes, and filters through layers of soil and rock in the ground, it dissolves or absorbs the substances it touches.