Wisconsin

Continuing obligations and residual contamination

Agency Wisconsin Department of Natural Resources

ASTM search distance Subject property only

Wisconsin lets some contamination stay in place after a cleanup is approved; the Wisconsin Department of Natural Resources (DNR) calls what remains above state standards residual contamination. To protect health and the environment, DNR often attaches continuing obligations to such a property: legal duties that the owner carries and that pass to each new owner when the property is sold. DNR sets them in the closure letter, its approval of the cleanup, under s. 292.12(2), Wis. Stats., and other laws. DNR notes that other names for them include environmental land use controls and institutional controls.

In a Phase I ESA

DNR's continuing obligations are the Wisconsin form of the state institutional and engineering control records that ASTM E1527-21 lists as a standard source. DNR says the state gives public notice of them by adding the property and its obligations to DNR's online remediation database, which it says was set up under s. 292.12(3), Wis. Stats. The general reading of a control listing is on the State/Tribal Institutional and Engineering Control Registries page. Five Wisconsin details shape how to read one.

Two obligations are common. DNR says the usual ones are handling contaminated soil properly if it is dug up, and getting approval before a water supply well is built. The well approval form is titled GIS Registry Site Well Approval Application (Form 3300-254).
Others are specific to the property. DNR's examples include keeping clean soil and plants, pavement or an engineered cover over contamination; telling the state if a building that limited the cleanup comes down, which may lead to more work; running and maintaining a vapor mitigation system; keeping industrial use where industrial soil standards were used for closure; and keeping a particular use named in the closure letter. The owner needs the state's permission before changing the part of the property where such a duty applies, and, unless someone else has taken on the duty by contract, must inspect, maintain and keep records of the conditions the closure letter names.
Old closures may point to a deed. DNR says that where a closure letter written before June 2006 required a deed restriction, the obligation is the one the deed restriction defines. Read the deed restriction as well as the letter.
Neighbors can carry them too. DNR says a land use control can apply to an off-site property reached by the contamination, even where its owner qualifies for the off-site liability exemption; see Liability clarification letters and exemptions.
They can come before closure. DNR may set a continuing obligation in an approved remedial action plan when a cleanup will take a long time; its example is a cap over an unlicensed landfill that must be kept up while groundwater and methane are monitored.

DNR adds one more duty: where a groundwater monitoring well could not be found and properly abandoned, the property owner must abandon it under s. NR 141.25, Wis. Adm. Code, once it is found.

Changing an obligation

A request to modify continuing obligations costs $1,050, plus any database fees, which DNR says can apply when obligations are imposed, changed or removed; the amounts are those DNR's fees page listed when read on October 13, 2026. Requests use Form 4400-237. The rules are ch. NR 725 (notification for residual contamination and continuing obligations) and ch. NR 727 (continuing obligations and reopening closed cases); see NR 700 rule series.

Where to look a site up

The RR Sites Map has a layer called Continuing Obligations Apply. Click the property, choose View Activity Details on BOTW, and open the file attached to the action Continuing Obligations Applied. See RR Sites Map.
BRRTS on the Web holds the activity and its documents, which DNR says may include the closure letter, property maps and contaminant data. The closure letter states the obligations.
The map page says the map does not show soil contamination left above residual contaminant levels at cleanups completed before August 1, 2002. For an older closure, read the closure letter rather than relying on the map.

Getting the file

For an active site, the BRRTS page sends you to the DNR staff member named on the activity's details page; for a closed site, to an RR program specialist, on DNR's RR Program staff contacts page. DNR prefers records requests by email, to DNRRecordsResponse@wisconsin.gov, and accepts them in any format; see Public Records Request.

Sources

Wisconsin Department of Natural Resources pages, read October 13, 2026, no modified date shown: