Water Well Decommissioning
Is that old windmill contaminating drinking water?
Probably not, but the well below may be. Often these wells are deteriorating and no longer used, but the well shaft is still a direct connection from the ground surface to the underlying aquifer. This connection can allow surface runoff to flow directly to the water-bearing zones, often carrying organic wastes, fertilizers, and other chemical residues such as pesticides and petroleum products into the groundwater. Small animals can fall into these wells, further adding to the contamination. Contaminants that enter an old, out-of-service well can move with the natural groundwater flow and into in-service water supplies such as a new well on the property or a neighbor's well. Once groundwater is contaminated, it is difficult, if not impossible to clean it up, and the process is always expensive.
What constitutes an illegal well?
Unused wells, especially those that are old and in disrepair or substandard, pose a major threat to groundwater quality and represent a serious threat to safe drinking water. State law refers to these as illegal wells. Open wells are also a safety hazard to humans and animals. A child can easily fall into an open well - a risk to human life that can be prevented.
There are thousands of these wells on farmsteads, acreages, and other rural areas throughout the state. Often, when a new well is drilled, the property owner neglects to properly decommission the old well or may have put off having it sealed.
Locating unused wells
It is not unusual for a windmill tower and well to be located in a cropped field. Not only does this location provide the potential for groundwater contamination from applied fertilizers and pesticides, it also decreases field efficiency. Planting, spraying, harvesting and other equipment must turn to avoid the well. Other locations of windmill towers and wells that are especially susceptible to contamination include: road ditches, livestock yards or holding areas, and in the immediate vicinity of streams.
While a windmill tower can be an excellent indicator, wells can be present at many other locations too. Rural property owners should carefully observe for any signs that a well might exist.
Some signs include:
- concrete pads where the legs of a windmill tower once stood;
- depressions where an old well pit or the walls of a dug well may have collapsed;
- an old stock tank in an over-grown area;
- a small area that is fenced-off, especially if there are also pipes sticking out of the ground;
- flat stones, a concrete slab, old boards, metal sheets, or other items that could be covering an old well shaft.
Sometimes there are no signs. One landowner discovered a 36-inch diameter, 50-foot-deep dug well when the front wheel of his tractor dropped into it. He did not know until then that this well was there, despite having grown up on that farm.
If there is an unused well on your property, begin the decommissioning process today. It's okay to keep the windmill for decoration or as a yard light support, but have the well properly sealed and do your part to protect groundwater quality, human health and safety.
Related Resources
