A tube well is a water well consisting of a long tube bored into the ground and sunk to the depth of the water table. Tube wells are fast and easy to install, making them particularly popular in developing nations where the infrastructure for larger and more involved well designs is not in place. There are some potential drawbacks to this design, including the risks of water contamination if the well is not sunk in an appropriate location. In Bangladesh, for example, widespread use of tube wells has led to an increase in arsenic poisoning because of natural arsenic deposits in the soil.
Several different techniques including auguring can be used to create the shaft for a tube well before sinking the tube, made of plastic, metal, or other materials. A cap at the bottom prevents leaching, while a screen traps particulates to keep them out of the well. Some tube wells are packed with gravel and sand to act as an additional filter. These materials trap particles in the water as it trickles toward the well.
Tube well installation is fast and very easy. Minimal skills are necessary, and it is possible to get a working well in place much more quickly than with other construction techniques. Organizations working on promoting access to potable water often include tube wells in their community programs. They can teach members of a community how to sink a well with the first installation, and then provide them with tools to make additional wells so the entire community will have access to clean water.
It is necessary to use a pump with a tube well to draw water up from the well to the surface. Pumps can be operated by hand or with an engine. Some rely on an electrical supply to run an electric motor and tend to be more environmentally friendly. Caps at the top of the tube well prevent contamination from above, keeping the contents of the well as clean as possible.
In some regions, residents may create a reservoir at the top of the tube well to create easy access to water. This can be a public health issue, as reservoirs may become traps for microbes, algae, and other organisms that could make people sick. Animals wallowing in the water could also introduce urine and feces. This may not be a problem for irrigation but could be a cause for concern in water used for bathing and cooking.