News Release


Wisconsin Department of Natural Resources


DNR experts urge developers and property owners to take proper steps to properly abandon any old wells before doing building demolition work.


That large pipe sticking up in the yard or poking out from the basement floor could be an old well.


"Old wells can cause serious groundwater contamination that damages other properties, especially if they are improperly broken-off and buried without being filled,” said Fred Bailey, Water Supply Specialist for the Department of Natural Resources in Wautoma. “They can provide a pipeline for surface water or sewage to get directly into the groundwater without being filtered, and the local groundwater and your health could be effected if the water gets contaminated.”


Demolition contractors must assure that old wells, like all utilities, are properly and permanently sealed prior to demolition. “Discovering old wells is common, “Bailey stated. "Property owners often don’t know that they have an old well because local governments rarely keep well records.


Since 1936, the DNR has required that a Well Abandonment Report be filed with the department for any well taken out-of-service. These wells should then have been properly sealed ("abandoned"), but many aren't.


Proper well abandonment does not mean merely capping-off the top. Often the entire depth of a drilled well can be filled with swelling clay called bentonite, which is applied slowly to avoid creating voids.


In sandy areas, smaller diameter pipes called driven point wells are used. These can often be found in basements and pits. They need to be filled with a cement grout slurry. For certain wells, such as extremely deep or large diameter hand dug wells, other materials may be allowed by code.


The Wisconsin Department. of Natural Resources recommends that well abandonment be subcontracted to a licensed well driller or pump installer familiar with the code requirements. Typical residential wells (6-inch diameter) will cost about $5 per foot of depth to seal properly. Large industrial wells (>10" diameter) can be more than a thousand feet deep, and may cost several thousand dollars to properly abandon.


The liability for improper well abandonment is considerable. Many times the DNR has required excavation of a site to look for a well that was mistakenly buried. Chemicals, sewage or old pumps can fall into wells resulting in great expense to bail or clean out the shaft before proper abandonment. The active wells of neighbors can get contaminated if poor work is done.


To learn more about proper well abandonment, contact a licensed well contractor, or the Wautoma Service Center at 920/787-4686 ext. 3032 for more information. You can also visit the DNR web site at: http://www.dnr.state.wi.us/org/water/dwg/abandon.htm