The Peru Gazette

While no well is pollution-proof, a dug well is at higher risk for contamination. A drilled well is more secure, but regardless of depth, it’s still vulnerable to surface pollutants near the wellhead. There’s no such thing as a well in “solid rock,” which by definition is a dry hole in the ground. Water flows into boreholes at various depths through bedding planes in sedimentary formations, and joints and fissures in all rock types. Contaminants are sometimes drawn into wells along these channels.

Source: National Groundwater Awareness Week is March 7-13 – – The Adirondack Almanack