Underground Storage Tanks FAQ

What is an Underground Storage Tank (UST) system?

According to the U.S. Environmental Protection Agency, an underground storage tank (UST) system is a tank (or a combination of tanks) and connected piping having at least 10 percent of their combined volume underground. Federal UST regulations apply only to underground tanks and piping storing either petroleum or certain hazardous substances.

Until the mid-1980s most underground storage tanks (USTs) were made of bare steel, which is likely to corrode over time and allow UST contents to leak into the environment. The greatest potential hazard from a leaking UST is that its contents (petroleum or other hazardous substances) can seep into the soil and contaminate groundwater, the source of drinking water for nearly half of all Americans.

The following types of tanks do not have to meet federal UST regulations:

  • Farm and residential tanks of 1,100 gallons or less capacity holding motor fuel used for noncommercial purposes;
  • Tanks storing heating oil used on the premises where it is 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;
  • Flow-through process tanks;
  • Tanks of 110 gallons or less capacity; and Emergency spill and overfill tanks.


How common are UST leaks?

The EPA has received 479,817 reports of UST system releases as of Sept. 2008, due to leaks, spills, and overfills. UST systems contain hazardous and toxic chemicals, and fumes and vapors can travel through the ground and collect in areas like basements, parking garages and underground vaults, where they may result in a threat to human health and safety.

Also as of September 2008, 455,096 cleanups of UST releases have been initiated, and 377,019 cleanups have been completed.

Gasoline, leaking from service stations, is one of the most common sources of groundwater pollution.

The EPA regulates USTs with the hopes of preventing releases, as clean up is difficult and expensive, and not always effective.


How is a release from a UST system reported?

It is the responsibility of an owner or operator of an underground storage tank system to report any suspected release to their state or local implementing agency within 24 hours, or within the reasonable time period established by that agency. A list of the EPA’s state and territory UST/LUST program contacts is available on the EPA web site.

UST owners and operators also are required to take immediate action to stop the release of petroleum or other hazardous substances from the UST and to ensure there is no threat to the safety of people located in the area of the release.

According to the EPA, UST owners and operators are not required to alert the implementing agency of above ground spills or overfills of petroleum of less than 25 gallons if the release can be contained and cleaned up within 24 hours.


How can I tell if a gasoline release has impacted my property?

In a perfect world, the top priority of every underground storage tank (UST) owner would be to detect and stop gasoline releases before they pose a threat to the health and safety of adjacent property owners. In actual practice though, many UST owners do not have (or do not properly use) sufficient protective equipment to detect and prevent leaks before they get out of hand. In some instances, UST owners simply fail to do anything about a leak for many months or years in the hopes of avoiding liability.

For this reason, people who live or work near a gas station must take steps to protect themselves and their property by paying attention to the“warning-signs” of a UST leak.

For instance, you should suspect a leak when you discover any of the following warning signs:

    1. The soil on your property has a petroleum-based odor.
    2. You notice an oily sheen on the surface of a nearby creek, pond or drainage ditch.
    3. Your drinking water tastes or smells like petroleum.
    4. You detect any sort of gas vapors in your basement or crawlspace.
    5. You observe heavy equipment removing soil and/or asphalt at the gas station.
    6. You observe a crew installing and/or testing narrow monitoring wells at the station.

If you encounter any of these warning signs, you should immediately contact your state environmental agency to determine whether a UST leak has been reported in your area. In addition, you should take steps to protect your legal rights.