CA Criteria for Tanks in Subsurface or Below Grade Structures

Effective January 1, 2013, AB 1566 makes changes to the UST regulatory program in California, specifically regarding the criteria for regulating tanks located in subsurface or below grade structures.

“Aboveground storage tank” or “storage tank” means a tank that has the capacity to store 55 gallons or more of petroleum and that is substantially or totally above the surface of the ground, except that, for purposes of this chapter, “aboveground storage tank” or “storage tank” includes a tank in an underground area.

“Underground storage tank” means any one or combination of tanks, including pipes connected thereto, that is used for the storage of hazardous substances and that is substantially or totally beneath the surface of the ground.

Discussions regarding vaulted tanks and tanks in basements have been going on the last few years, with discrepancies between tank owners and the State Water Resources Control Board regarding whether an AST located in an underground area, such as a basement, cellar or pit, should be considered a UST, and when that should happen.

Assembly Bill No. 1566 is “An act to amend Sections 25270.2, 25270.4, 25270.12, 25281, and 25281.6 of, and to add Sections 25270.4.1, 25270.12.1, and 25270.12.5 to, the Health and Safety Code, relating to aboveground storage tanks.”

This Flow Chart is a straightforward way to define whether a tank will be classified as a UST or an AST.

Flow Chart of AB 1566 UST Provisions

For more information, and to read the bill, go to the Official California Legislative Information website.