A well is an excavation or structure built to access groundwater from underground aquifers. Wells are the primary water source for many homesteads, providing a reliable supply independent of municipal systems. Well types include drilled wells, dug wells, and driven wells, each suited to different geological conditions and water requirements. The depth, yield, and water quality of a well depend on the local geology and aquifer characteristics.
Drilled wells are the most common modern well type. A drilling rig creates a borehole 15 to 30 centimeters (6 to 12 inches) in diameter, penetrating to depths of 30 to 150 meters (100 to 500 feet) or more. A steel or PVC casing is installed to prevent collapse and seal out surface contamination. The annular space between the casing and the borehole is filled with grout. A well screen at the bottom allows water to enter while excluding sand and gravel. Drilled wells are the most expensive option but provide the highest quality water and longest service life.
Dug wells are excavated by hand or machine, typically 1 to 2 meters (3 to 6 feet) in diameter and 5 to 15 meters (15 to 50 feet) deep. They are lined with stone, brick, concrete, or metal culvert sections. Dug wells are vulnerable to surface contamination from runoff and are not recommended as a primary drinking water source in areas with intensive agriculture or septic systems.
Driven wells (sand points) are constructed by driving a small-diameter pipe with a screened point into a shallow aquifer. They are suitable where the water table is within 7 meters (20 feet) of the surface and the soil is sand or gravel. Driven wells are the least expensive option but have limited yield and are easily contaminated.
Submersible [[Ram Pumps]]s are the standard for drilled wells. The pump is suspended in the well below the water level and pushes water to the surface. Pump capacity is matched to the well's yield rate, measured in liters per minute. A pressure tank maintains system pressure and reduces pump cycling. Jet pumps are used for shallow wells and operate by creating suction at the surface. Hand pumps provide a backup water supply during power outages.