What is a Groundwater Well?

A groundwater well is an underground receptacle for drawing and containing groundwater for the purpose of furnishing potable water for drinking, cooking, and plumbing. The water source is called groundwater because the well taps into an underground aquifer, which consists of permeable rock and sediment in which pockets or fractures trap water generated from natural springs and wetlands. The groundwater well is drilled into the aquifer to the point of reaching the water table, or the depth at which groundwater becomes accessible.

Groundwater wells are a necessity in areas where municipal water systems do not deliver clean water to residential homes, farms, and commercial facilities. In fact, the majority of people who live and work in rural areas typically rely upon wells for their water and plumbing needs. While many people prefer the taste and higher mineral concentration often found in groundwater, there can be a few drawbacks to this type of system. For one thing, the water source can run dry, requiring a new groundwater well to be drilled with little advance notice. For another, bacterial or chemical contamination of the source can occur, which can only be detected by periodic groundwater testing.

The mechanical operation of a modern groundwater well is fairly simple. First, the water is drawn as needed via a pump, usually a submersible pump powered by electricity. The water is then passed through a fine screen to filter out sedimentary particles before reaching its final destination. In contrast, primitive water wells sometimes found on farms or older homesteads usually lack a mechanical pump, requiring hand cranking by a human to bring water to the surface. Other types of wells may be driven by a different kind of mechanical device, such as a windmill.

The construction and capacity of a groundwater well also varies depending on its location. If the ground is soft and the water table relatively high, it may only be necessary to drill to a depth of 100 feet (30.48 meters) or less to construct what’s known as a shallow or bored well. Wells drilled to access water hidden in deposits of loose sediment and other problematic locations are referred to as unconsolidated wells. Since the formation may tend to collapse, these wells are usually reinforced with a cement casing and a level of stones at the bottom to keep the well from needlessly refilling itself due to uncontrolled seepage. In contrast, wells driven into solid rock formations are called consolidated wells, and usually require a depth of 250 feet (76.2 meters) or more.