Abandoned Wells Pose Risk To Human Health

As spring approaches we are often inclined to develop a list of things to accomplish for the upcoming warmer weather. If you have an old well that is not being used or not operational and is to sealed, please add “seal well” to your list.

Abandoned wells provide a potential avenue for surface or shallow ground water entering your drinking water supply. They are located in crop fields, livestock yards and pastures, farmsteads, small well houses and outbuildings, basements, garages, and pits. Often abandoned wells are marked by old windmills. The old wells generally have short, poor quality or deteriorated casing and may be uncapped. These conditions allow for seeping or direct injection of contaminated water into deeper ground water supplies. If the abandoned well is in close proximity to a working well, the contamination may move more rapidly into the deeper aquifer and contaminate a drinking water supply.

Property owners in Stephenson and Carroll Counties may seal their own home or farm’s abandoned well, however, commercial properties must be sealed by an Illinois licensed well driller. All individuals wishing to seal an abandoned well in Stephenson or Carroll County must submit well sealing application to the County Health Departments accompanied with a fifty dollar fee. An employee of the County Health Department must be present when wells are sealed by non-licensed individuals.

To seal a well,all obstructions such as pipe and pumps must be removed from the well. The diameter and depth of the well must be determined to obtain sufficient materials to properly seal a well. Before starting to seal a well, chlorine needs to be added to the well in sufficient amounts to bring the chlorine level to one hundred parts per million (generally several gallons and two cups of rapid-release chlorine granules is adequate). If a construction report is not available, the seams between geological layers must be filled with bentonite or neat cement for at least ten feet above and below the layer. Only bentonite or neat cement may be used from twenty feet below the bottom of the casing to within two feet of the surface. Sealing abandoned dug wells require a different strategy. Beginning with a twelve inch layer of bentonite and then followed by a five feet thick layer of limestone chips. This layering sequence continues to within several feet of the surface. Soil may be used to bring it to grade level.

The Stephenson and Carroll County Health Department Environmental Health Divisions look forward to working with you in sealing abandoned wells. Please contact Stephenson County at: 815-599-0344 or stop in at 295 W. Lamm Rd., Freeport or Carroll County at 815-244-8855 or stop in at 822 S Mill St, Mt. Carroll, Illinois 61053.