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Offsite contamination - contamination that crosses property lines


When contamination from one property crosses a property line and affects another property, it is know as an "offsite discharge” of contamination under § 292.13, Wis. Stats. [PDF exit DNR].

Generally, the DNR will not ask owners of properties to take environmental response actions if the contamination did not originate on their property. The fundamental obligation for these offsite property owners is to allow access to their property so that others may investigate and clean up the contamination, and to maintain environmental land use controls if they were required as part of the approved cleanup.

Liability exemptions

Liability exemptions for offsite contamination

When contamination has crossed a property line, the owner of property with contamination that originated on another neighboring property is not responsible for cleanup, but only if he or she can demonstrate that his or her property is not the source of any of the contamination. Generally, this happens when the person who is responsible completes their investigation of the contamination and shows where it originated and how far it spread.

Sometimes, however, this is difficult and time-consuming, and affected neighbors may need to refinance or sell their properties before the investigation into where the contaminate originated is completed. Owners of properties affected by contamination from other properties have the option to demonstrate that the contamination did not originate on their property and can obtain a written liability exemption from the DNR.

Property owners can obtain this written exemption letter from the DNR for a fee, under ch. NR 749, Wis. Adm. Code. However, please note that the statutory liability exemption applies whether or not the DNR writes such a letter, and that the liability exemption is not transferable to future owners.

In order to obtain this liability exemption, a property owner must demonstrate that:

  • contamination on his or her property originated somewhere else;
  • the owner did not possess or control the property where the contamination originated; and
  • the owner did not possess or control the hazardous substance that contaminated the property where the contamination originated, and did not cause the discharge of this hazardous substance.

A property owner also must:

  • allow the person who is responsible for the contamination, as well as the DNR, reasonable access to his or her property for investigation and cleanup of the contamination; and
  • avoid actions that could worsen the contamination, not interfere with actions taken in response to the contamination and comply with conditions that the DNR finds necessary.

If a property owner is eligible for a liability exemption for contamination from another property, the owner will be exempt from the following statutory requirements for that source of contamination:

  • taking environmental response actions, including investigation and cleanup of contamination and responding to state orders for environmental preventive measures;
  • reimbursing the DNR for costs associated with any DNR response to that contamination; and
  • emergency or special orders for protection of public health, safety or welfare.

If an offsite property owner is interested in potential health impacts of the contaminants, he or she may consult the Wisconsin Department of Health Services, Environmental Health division [exit DNR].

Offsite exemptions and land use controls

Often residual contamination remains after an approved cleanup and sometimes the approval includes environmental land use controls – such as a grass or asphalt cap to cover remaining contamination – intended to reduce the impact from the residual contamination. For more general information about land use controls, please see Residual contamination.

When contamination has moved offsite, the land use controls may also apply to neighboring properties. So while the owner of a neighboring property may not be responsible for cleaning up the contamination, he or she may become responsible for a land use control. The following general requirements, applicable to both the property where the contamination originated and to other affected properties, apply when an environmental land use control is included in the cleanup approval. The requirements regarding land use controls apply even if the owner of another impacted property is protected by the offsite liability exemption.

  1. The property owner must obtain prior DNR approval to construct or reconstruct a water supply well.
  2. If the residual contamination is disturbed, the property owner is responsible for proper sampling, handling and treatment or disposal of the contamination.
  3. If specified in the cleanup approval, the owner must periodically inspect the physical land use control, maintain it and record the maintenance activities. For example, this often means taking good care of pavement that covers contaminated soil.
  4. The owner must obtain prior written approval from the state before changing the physical conditions specified in the land use control.

Information about specific properties with residual contamination and the specific land use controls that apply to them may be found in the RR Program's Wisconsin Remediation and Redevelopment Database (WRRD). Documents in this online system include the closure letter that specifies the continuing obligations imposed by the land use control.

Exemption application

Application for an offsite liability exemption

The offsite liability exemption application form includes instructions and describes the information needed by the DNR in order to grant an offsite liability exemption.

Liability clarification letters

Other situations and options – liability clarification letters

If a property owner is unable to meet the conditions to obtain an offsite liability exemption, the DNR can instead provide a liability clarification letter for the same fee of $700. For more information about this option, please see our fact sheet General liability clarification letters (RR-619) [PDF].

Liability clarification letters may be helpful when:

  • a property owner is considering purchase of property affected by offsite contamination; the clarification letter would state the conditions under which the liability exemption would be available to an owner;
  • widespread contamination has affected multiple individual properties; the DNR can write a single liability clarification letter that describes the conditions under which an offsite liability exemption would be available to each owner affected by the same source of contamination;
  • there is credible evidence that groundwater contamination has moved onto a property from somewhere else, but no groundwater samples have been collected and analyzed from the property; or
  • there is known groundwater contamination in the area and a likelihood that a property may become affected by contamination from somewhere else.