1,Drill the well away from any potential contaminants.
Animal feedlots, buried fuel tanks, waste disposal and septic systems can all pollute groundwater. Wells should be drilled in places where they can easily be reached for maintenance, and located at least 5 feet (1.5 meters) from building sites.
2,Choose the appropriate construction method.
Drilled wells may be bored with an auger or rotary tool, smashed out with a percussion cable or cut with high-pressure jets of water. Wells are dug when there is sufficient water near the surface and no intervening dense rock. After a hole is made with shovels or power equipment, a casing is lowered into the aquifer, and the well is then sealed against contamination. As they are shallower than driven or drilled wells, they are more likely to go dry when drought lowers the water table.
Wells are driven by attaching a steel driving point to a stiff screen or perforated pipe, which is connected to solid pipe. An initial hole wider than the pipe is dug, then the assembly is pounded into the ground, with occasional turnings to keep the connections tight, until the point penetrates the aquifer. Wells can be hand-driven to depths of 30 feet (9 meters) and power-driven to depths of 50 feet (15 meters). Because the pipe used is of small diameter (1.25 to 12 inches, or 3 to 30 centimeters), multiple wells are often driven to provide sufficient water.
Augers can be either rotating buckets or continuous stems and can be turned either by hand or with power equipment. They work best in soils with enough clay to support the auger and don't work well in sandy soil or dense rock. Auger-bored wells can be drilled to depths of 15 to 20 feet (4.5 to 6 meters) by hand and up to 125 feet (37.5 meters) with power augers, with diameters ranging from 2 to 30 inches (5 to 75 centimeters).
Rotary drills exude water based drilling fluid or compressed air from holes in a rotating bit to make drilling easier and pump out the drill cuttings. They can drill to depths of 1000 feet (300 meters), creating holes from 3 to 24 inches (7.5 to 30 centimeters) wide. While they can drill faster than other drills through most materials, they have trouble drilling through rock, and the drilling fluid makes it tough to identify material brought up from water-bearing strata.
High-pressure water jets use the same equipment as rotary drills, without the bit, as the water both cuts the hole and lifts out drilled material. This method takes only minutes, but jet-drilled wells can be no more than 50 feet (15 meters) deep, and the drilling water needs to be treated to prevent it from contaminating the aquifer when the water table is penetrated.
3,Finish the well.
Once the well is drilled, casing is inserted to prevent the water from wearing away and being contaminated by the sides of the well. This casing is usually narrower in diameter than the well hole itself and sealed in place with a grouting material, commonly either clay or concrete.A bag to filter out sand and gravel are inserted in the casing, then the well is capped with a sanitary seal and, unless the water is already under pressure, a pump is attached to bring the water to the surface.