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.
Information presented within this section of this Water Web site has been reviewed by University of Nebraska-Lincoln Wellhead Management and Drinking Water team members David Shelton, Sharon Skipton, Bruce Dvorak, Wayne Woldt, and Jan Hygnstrom.
UNL Extension Publications
*Note: Most NebGuides are available in a web page html format. If you prefer to print these articles and read offline select the PDF version. You will need the Adobe Acrobat Reader to open and print PDF files. All PDFs are 2-4 pages unless otherwise noted. You can download the current version of Adobe Acrobat Reader at no charge from the Adobe Web site.
Decommissioning Water Wells to Protect Water Quality and Human Health
Describes the process and available resources when an illegal well must be abandoned.
PDF version* (717 KB)
Drinking Water: Bacteria
Bacteria in drinking water can endanger health. Learn how contamination occurs, how to have water tested, and which treatment to use. Viruses or other microbial organisms are not addressed.
PDF version* (672 KB)
Drinking Water: Nitrate-Nitrogen
Nitrate-nitrogen is sometimes present in drinking water. At certain levels it can present a health risk. Properly locating and constructing wells, along with regularly testing water can help manage risk.
PDF version* (645 KB)
Drinking Water Treatment: Shock Chlorination
Shock chlorination can eliminate coliform, fecal and/or E. coli contaminants from water systems. This publication explains the shock chlorination process.
PDF version* (674 KB)
Shock Chlorination Calculator
Nebraska Department of Health and Human Services - Statutes and Regulations
Title 178 Chapter 10
Regulations governing licensure of water wells and pump installation; contractors and certification of water well drilling; pump installation and water well monitoring supervisors.
Title 178 Chapter 12
Regulations governing water well construction, pump installation and water well decommissioning standards.
Private Water Systems Handbook is available for purchase.
This comprehensive handbook is a valuable tool for users of private water systems. It includes information on wells, pumps, water distribution systems, pressure tanks, and water sources, as well as water needs, testing, treatment, conservation, and system maintenance. Cost is $32.00 plus shipping and handling. Order MWPS-14, ISBN 0-89373-105-6 by web. (While it is an excellent source of information, it is important to check state and local laws, regulations, codes and licensure since requirements can vary depending on location.)