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Idaho

Regulated Underground Storage Tanks

Agency Idaho Department of Environmental Quality
ASTM search distance Subject property and adjoining properties

Idaho regulated underground storage tanks

Underground storage tanks in Idaho are regulated by the Idaho Department of Environmental Quality (DEQ). DEQ says it has EPA approval to operate the Idaho UST program, and it regulates tanks under the "Rules Regulating Underground Storage Tank Systems" (IDAPA 58.01.07). DEQ says it maintains a database of regulated UST sites in Idaho.

In a Phase I ESA

DEQ's regulated tank records are the Idaho form of the state registered storage tank records that ASTM E1527-21 lists as a standard source. The general reading of a registered tank listing is on the UST / AST page. A tank record says a tank system exists or existed. Releases are a separate record, the Leaking Underground Storage Tank record.

Three Idaho details shape the search.

  • The database is of regulated tanks. DEQ lists the tanks that are exempt from its tank rules: farm and residential tanks of 1,100 gallons or less holding motor fuel for noncommercial purposes, tanks storing heating oil for on-site consumption, tanks on or above the floor of underground areas such as basements, septic tanks and systems for collecting stormwater and wastewater, and emergency spill and overfill tanks that are emptied immediately after use. Check for those tanks by other means. See aboveground and heating oil tanks.
  • A regulated tank need not be buried. DEQ defines a UST as one or any combination of tanks and connective pipes used to contain petroleum or other regulated substances with 10% or more of its volume, including underground pipes, beneath the ground surface.
  • DEQ ties tanks to property sales. DEQ says it is important to determine whether a UST, even one no longer in use, exists or existed on a property before a purchase or sale. It says any past or newly discovered contamination must be disclosed to a potential buyer and reported to DEQ to determine if remedial action is required.

The paperwork a regulated tank generates

DEQ's rules and forms pages show the paper a regulated tank can generate.

  • Notifications. The UST Notification Form covers a new tank or piping installation, a tank closure, a change of owner, a piping replacement and other facility updates. Notice is due at least 30 days before installing a tank, at least 30 days before permanently closing one, and within 30 days of acquiring one.
  • Inspections and tests. DEQ says its staff inspect each regulated UST system every 3 years. It publishes forms for walkthrough inspections, release detection equipment tests, line leak detector and line tightness tests, overfill and containment tests, and cathodic protection tests.
  • Permanent closure. When permanently closing a regulated tank, the owner or operator must evaluate the presence of a release where contamination is most likely to be present. For a closed tank, ask for the closure notification and the results of that evaluation.
  • Financial responsibility. Each regulated UST must have petroleum contamination or pollution insurance, or proof of financial responsibility.

Where to look a site up

  • DEQ's tank pages link its UST and LUST Database. The listing is found there.
  • DEQ's Facility Mapper page links a map tool that has an Underground storage tank (UST) program category. DEQ says that for sites with UST facilities, the UST hyperlink in the tool's Feature Information tab takes the user directly to the UST-LUST database.
  • DEQ's tank pages list staff contacts for the program. The DEQ State Office is at (208) 373-0502.

Getting the file

DEQ says notifications and installation documents are submitted to it. The pages read do not say which inspection and test forms DEQ keeps, so ask the owner or operator for those as well. DEQ takes requests under the Idaho Public Records Act through its Public Records Request page, which carries buttons to submit a request online, track its status and search the request archives.

Sources

Idaho Department of Environmental Quality pages, read October 1, 2026:

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