Wells that are unused or abandoned pose a serious risk to ground water quality. Improperly abandoned wells threaten drinking water due to the potential of leaking contaminated surface water into aquifers that potentially provide drinking water to private or public wells.

If a water well is being replaced due to quality of drinking water, the original well is a direct threat to the new well if not properly sealed.

Examples of pollutants that can contaminate an improperly abandoned well includes: flood waters, septic, pesticides, fuels, industrial chemicals, disease causing bacteria and viruses.

Due to these risks, abandoned wells must be plugged or capped.