What IDEM Regulates

Underground Storage Tanks

In Indiana, a regulated underground storage tank (UST) system is comprised of a tank, or combination of tanks, and piping that holds regulated substances and has at least 10 percent of its total volume underground. The Office of Land Quality (OLQ) enforces UST regulations to ensure that all regulated USTs meet the requirements for release detection, spill and overflow prevention, and corrosion protection. OLQ also ensures that tanks not meeting those requirements are properly closed or upgraded.

What IDEM Does Not Regulate

These tank systems are specifically excluded from UST regulations, but they may still be covered by other rules:

  • Tanks that store hazardous waste.
  • Farm or residential tanks containing less than 1,100 gallons of motor fuel for noncommercial use.
  • Tanks containing heating oil used on the premises where they are stored.
  • Tanks on or above the floor of underground areas, such as basements or tunnels.
  • Septic tanks and systems for collecting storm water and wastewater.
  • Equipment or machinery that contains regulated substances for operational purposes, such as hydraulic lift tanks and electrical equipment tanks.
  • Pipeline facilities, including gathering lines.
  • Tanks holding regulated material with a capacity of less than 110 gallons (unless the total capacity of multiple USTs holding the same material is 110 gallons or greater).
  • Wastewater treatment tank systems that are part of a wastewater treatment facility.
  • UST systems that contain a minimal concentration of regulated substances.
  • Emergency spill or overflow containment UST systems that are emptied immediately after use.

Aboveground Storage Tanks

An assortment of federal and state laws and rules apply to aboveground storage tanks (ASTs). Local units of government also have certain requirements. The Aboveground Storage Tanks page summarizes AST regulatory requirements. Contact IDEM if you are not sure if your storage tank is regulated.