A Drilled water well in New Hampshire and Vermont consists of a hole bored into the ground by a drill rig. The top section of the well is lined with a steel pipe referred to as casing by well contractors. Most often a 6” hole is drilled. The casing prevents the collapse of the walls of the well and prevents surface or subsurface contaminants from entering the water supply. Casing is seated 10 feet into solid competent bedrock. The casing must also have a drive shoe attached to the bottom to prevent damage during driving and to make a good seal with the formation. With the rolling hills of NH, each area requires different footage of casing, as bedrock could be 20 ft below ground, or 100 ft. In some applications, a grout seal of cement or bentonite may also be recommended or required to prevent contamination. After the casing is set into place and sealed, the drilling continues through solid bedrock, drilling through “fractures” until the driller is satisfied the well yields more than enough to supply the demand. During the drilling process it is necessary to use compressed air to determine the yield before completion. Compresses air also blows up the cuttings.