Contaminated wells should be treated or capped. Disused wells should be capped.

Unused/abandoned wells create multiple potential environmental hazards. As well as being a safety risk for example children and animals falling into them, they provide a direct connection to the water source that others are consuming and therefore the potential for water resources to be contaminated. pollution may be through unsanitary items being dumped into them, from floodwaters, or even from accidental or intentional dumping of hazardous chemicals.

Apart from the pollution of water resources, improperly filled and sealed wells pose the risk of accidents, especially affecting children and people with disabilities. Large-diameter open wells, especially old dug wells, pose safety hazards for small children and animals. In recent years, there have been instances in Italy, Missouri, and Kansas where children have fallen into wells. Although such occurrences are infrequent, they should never be allowed to happen.

Water pollution
Loss of biodiversity and ecosystems

Water pollution due to open abandoned wells.

Inadequate protection of wells can create a risk of water source pollution. Abandoned wells can provide direct pathways for contaminants to enter aquifers, particularly if these wells have not been maintained. The direct pathway between the surface and the aquifer means that any pollutant that enters the well will have the potential to pollute the groundwater.

Unused and improperly filled and sealed wells are a significant threat to groundwater quality. If not properly filled with impermeable caps, unused wells can provide a direct route for contaminated surface or soil water to enter the water in aquifers. Water that gets into unused wells bypasses the purifying action that normally takes as water is filtered by layers of soil and porous stone. Because groundwater flows in soil and bedrock formations (aquifers), pollution that enters old wells can enter nearby drinking water wells contaminating drinking water.

Seal open abandoned wells

Create a survey to identify, map (using GIS where possible), and monitor in-use and out-of-service wells in order to plan for their proper closure and capping.

Properly close and seal out-of-service wells. Otherwise, they pose a threat to groundwater quality and a potential safety hazard.

Determine the environmental implications of the way wells are sealed and consider soil types, water tables, and materials used. For example, contaminated surface water can enter a well if the well casing does not extend high enough above the ground surface and the well cap has been broken or removed; or if there are cracks or holes in the casing due to damage or age-related deterioration.

An estimated 400,000 private water wells in Illinois provide drinking water to approximately 1.3 million people. Each year, many of these wells are abandoned when they are replaced with new wells or when homes are connected to community water systems. A large number of these abandoned wells are large-diameter dug wells constructed with brick or stone casings, and range in depth from 20 to 50 feet.

These abandoned wells create pose a health and safety hazard when they are not properly sealed or not sealed at all. When abandoned wells are left open, children, animals, or even adults can fall into them, causing injury or death. To prevent such accidents, all abandoned wells must be properly sealed. Abandoned wells serve as a route for contaminating groundwater. Contaminated surface water, agricultural runoff, and effluent from private sewage disposal systems can enter the groundwater through such wells and cause pollution of other wells in the area used for drinking water.

Number of abandoned wells that were sealed and closed following environmental and personal safety guidelines

Prevention of environmental damage

Time and money for well mapping, recording, monitoring and capping.