Many types of rock make good aquifers, but sandstone and chalk are the best known. Aquifers allow people to live and work even in places where there is little surface water such as deserts.

One of the world's biggest aquifers lies under much of Australia (The Great Australian Basin) and farmers tap into it to provide both irrigation water and drinking water for livestock. An immense aquifer also underlies the Great Plains region of the U.S., and this is heavily used to allow crop farming.

An acqueclude is a band of rocks that does not allow water to flow through it.

Rocks that make ] include granite, clay and shale. In general a spring occurs at the junction of an aquifer and an aquiclude, the spring appearing at the top of the and at the bottom of the aquifer.

Aquifers are often used as a source of water for irrigation because the flow of water is very reliable.