Underground Storage Tanks

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. The tank system includes the tank, underground connected piping, underground ancillary equipment, and any containment system. The federal UST regulations apply only to underground tanks and piping storing either petroleum or certain hazardous substances.

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.

Some state or local regulatory authorities, however, may include these tank types in their UST regulations. Be sure you check with these authorities if you have questions about the requirements for your tank type.

Also, some tank types only need to meet the federal UST requirements for cleaning up a release (these tank types have been deferred from needing to meet most other federal UST requirements). Some examples of these tank types are field-constructed tanks, UST systems containing radioactive material, USTs that are part of an emergency generator system at nuclear power generation facilities, and airport hydrant fuel distribution systems.

Other storage sites, such as surface impoundments, are not covered by the federal requirements.

For more detailed information on the applicability of federal UST requirements for different types of USTs, please refer to Subpart A of Part 280 of the Code of Federal Regulations (CFR).

Top of page