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Off-site contamination - contamination that crosses property lines


When contamination from one property crosses a property line and affects another property, it is known as an "off-site discharge” of contamination under § 292.13, Wis. Stats..

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 obligations for off-site property owners are to:

  • allow access to their property so that others may investigate and clean up the contamination;
  • avoid interference with the investigation and cleanup;
  • avoid actions that may worsen the contamination; and
  • maintain environmental land use controls (also known as continuing obligations) if required as part of the approved cleanup.

Fact sheet: When Contamination Crosses A Property Line - Rights And Responsibilities Of Property Owners (RR-589)

Liability Exemptions

Liability Exemptions For Off-Site Contamination

When contamination has crossed a property line, the owner of the property with the contamination that originated on another neighboring property is not responsible for cleanup 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 where 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 contamination 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.

Property owners can obtain a written off-site liability exemption determination letter from the DNR — which addresses whether the criteria for the off-site liability exemption have been met — for a fee, under ch. NR 749, Wis. Adm. Code. However, please note that the exemption applies if the statutory criteria for the off-site liability exemption are met, whether or not the DNR writes such a letter. Also, the written letter only applies to the owner to whom it is addressed.

To qualify for this environmental liability exemption, a property owner must demonstrate that:

  • contamination on the property originated from somewhere else;
  • they did not possess or control the property where the contamination originated; and
  • they 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.

To maintain eligibility for the exemption, a property owner also must:

  • allow the person who is responsible for the contamination, the DNR and their representatives, consultants and contractors 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 any other conditions that the DNR finds reasonable and necessary to ensure that the DNR and/or responsible party can adequately respond to the discharge.

An off-site property owner interested in obtaining information about the potential health impacts of the contaminants may consult the Wisconsin Department of Health Services, Environmental Health division.

Land Use Controls On Off-Site Properties

Residual contamination may remain after an approved cleanup. Environmental land use controls (also referred to as continuing obligations), such as a grass or asphalt cap to cover remaining contamination, may be approved as part of the cleanup to reduce the impact of the residual contamination. See the Residual Contamination webpage for more general information about land use controls.

When contamination has moved off-site, the land use controls may also apply to an off-site property. An off-site property owner may become responsible for a land use control, even where they qualify for an off-site exemption.

The following general requirements apply when an environmental land use control is included in a cleanup approval. The requirements for land use controls apply to both the source property where the contamination originated and any affected off-site properties, even if the off-site liability exemption applies.

  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 (e.g., maintaining pavement that covers contaminated soil.)
  4. The owner must obtain prior written approval from the DNR before changing or disturbing 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. Documents in this online system include the closure letter that specifies the continuing obligations imposed by the land use control.

View the Brownfields Fundamentals On Demand Webinars - Locating Brownfields for instructions on how to use the Wisconsin Remediation and Redevelopment Database to locate records and mapped sites.

Exemption Application

Application For An Off-Site Liability Exemption Determination Letter

The off-site liability exemption determination letter application form includes instructions and describes the information needed by the DNR to write an off-site liability exemption determination letter.

Off-Site Liability Exemption Application (Form 4400-201)

Liability Clarification Letters

Other Situations And Options – Liability Clarification Letters

The DNR can provide a liability clarification letter for a fee of $700 for any property. For more information about this option, please see our General Liability Clarification Letters (RR-619) fact sheet.

Liability clarification letters may be helpful when:

  • a property owner is considering a purchase of property affected by off-site 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 off-site liability exemption would be available to each owner affected by the same source of contamination.