Brownfields_Content Page_Petroleum contamination and leaking underground storage tanks

Petroleum contamination and leaking underground storage tanks

Gasoline, oil and other petroleum products are used daily in Wisconsin businesses and homes. Many petroleum discharges come from storage tanks, known by the acronyms UST (underground storage tank), AST (aboveground storage tank) and LUST (leaking underground storage tank).

The Department of Agriculture, Trade and Consumer Protection (DATCP) maintains Wisconsin's tank registration database and is responsible for tank regulations for both underground and aboveground tank systems. Direct questions regarding tank registration and operator licensing to DATCP’s Bureau of Weights and Measures.

Tank system owners and operators, and owners of properties with tank systems, are required by state law to report discharges to the environment immediately (Wis. Stat. § 292.11).

When petroleum products are discharged into the environment from petroleum storage tanks, the Wisconsin Department of Natural Resources (DNR) oversees the cleanup. 

Wisconsin Storage Tank Laws and Regulations

Tank Closure Site Assessments (TSSAS)

Tank closure requirements are summarized in DATCP's Permanent Closure of Storage Tank Guidance and sampling requirements are summarized in DATCP's Tank System Site Assessment (TSSA) Guidance.

Submit reports of tank system site assessments (TSSAs) to the appropriate regional RR Program mailbox and project manager (if known), as well as to the DATCP Bureau of Weights and Measures.

Contact DATCPWMcompliance@wisconsin.gov (608-224-4942, Option 4) with any questions about TSSAs.

Tank Removal Program Funding

Permanent closure of abandoned petroleum underground storage tank (UST) systems is required. UST systems must be removed by Wisconsin-certified assessors and remover-cleaners (Wis. Admin. Code § ATCP 93.560).

Under the DNR Tank Removal Program, the DNR obligates $100,000 annually for state-funded removals of eligible abandoned UST systems. The systems are identified and prioritized in collaboration with the DATCP and the Wisconsin Department of Justice (DOJ). 

In accordance with Wis. Stat. § 292.64, a state-funded removal is allowed if the DNR determines a UST is abandoned and the owner is unable to pay for its removal. Eligibility requirements include all of the following:

  • An application signed by the owner that includes an access agreement
  • An agreement to place a lien on the property upon completion
  • A financial statement worksheet
  • Three years of state tax records
  • A deed for the property on which the UST system is located

Federal Energy Act Reports

Federal law requires states to collect information about the sources and causes of discharges to the environment from USTs and include that information in their public records. The DNR’s 2025 Report includes data collected from Oct. 1, 2024, to Sept. 30, 2025.