What Is An Underground Storage Tank (UST) System?
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/local regulatory authorities, however, may inc
