Bulletin 74-90 Introduction

Improperly constructed, altered, maintained, or destroyed wells are a potential pathway for introducing poor quality water, pollutants, and contaminants to good-quality groundwater. The potential for groundwater quality degradation increases as the number of well Improperly constructed, altered, maintained, or destroyed wells can facilitate groundwater quality degradation by allowing:

  • Pollutants, contaminants, and water to enter a well bore or casing;
  • Poor quality surface and subsurface water, pollutants, and contaminants to move between the casing and borehole wall;
  • Poor quality groundwater, pollutants, and contaminants to move from one stratum or aquifer to another; and,
  • The well bore to be used for illegal waste disposal.

Permanently inactive or “abandoned” wells that have not been properly destroyed pose a serious threat to water quality. They are frequently forgotten and become dilapidated with time, and thus can become conduits for groundwater quality degradation. In addition, humans and animals can fall into wells left open at the surface.