In Wisconsin, an unused well must be filled and sealed by a DNR-licensed well driller or pump installer. Homeowners can’t do it themselves. It’s required when a well has been unused for more than 90 days, still tests positive for bacteria after 3 batch chlorinations by a licensed pro, or is a hazard. The City of Madison lists typical costs of $800 to $1,500.
Updated October 2026
When it’s required
Under NR 812, a well must be filled and sealed when:
- It has been unused for more than 90 days (3 years for a seasonal well).
- It still tests positive for bacteria after 3 batch chlorinations by a driller or pump installer. This rule is new as of March 1, 2026.
- It is a hazard, or it doesn’t meet code.
- The pump setup no longer works.
- Buildings on the property are about to be torn down, or new construction is about to start. The well must be sealed first.
Who can do it
- Since June 1, 2008, only licensed well drillers or pump installers, or their employees, may fill and seal a well.
- The contractor files a filling and sealing report with the DNR.
Why it matters
An open or unused well is a direct path from the surface to the groundwater. In the Driftless area, thin soils and cracked rock already make groundwater easy to pollute.
Common situations
- A new well replaced the old one, and the old one was never sealed.
- An old farm well or well pit turns up during a home sale.
- A well kept failing bacteria tests.
Cost and help paying
- The City of Madison lists a typical cost of $800 to $1,500. Your well can differ, so ask for a written estimate.
- DNR Well Abandonment Grant: pays 75% of eligible costs for households with income of $65,000 or less, with smaller awards from $45,000 to $65,000. You must get DNR approval before the work starts. Work done before approval isn’t reimbursed. DNR grant contact: 608-228-9403.
- City of Madison: the city has offered partial reimbursement of well abandonment costs. Check with Madison Water Utility for eligibility.
When you need a licensed professional
- Any filling and sealing job. Wisconsin doesn’t allow homeowners to do it.
- Checking whether an old well on your land is still in use or needs to be sealed.
Related
- Grants and financial help for well owners
- Buying or selling a home with a well
- Getting a new well for a new home
- Coliform or E. coli in your well
- What well work costs in Wisconsin
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