### Question
What is the definition of underground storage tank?


### Answer
The definition of **underground storage tank** is as follows in *42 U.S.C. § 6991*:

> any one or combination of tanks (including underground pipes connected thereto) which is used to contain an accumulation of regulated substances, and the volume of which (including the volume of the underground pipes connected thereto) is 10 per centum or more beneath the surface of the ground

#### Citation:
  - *42 U.S.C. § 6991*
  - Heading: **CHAPTER 82-SOLID WASTE DISPOSAL > SUBCHAPTER IX-REGULATION OF UNDERGROUND STORAGE TANKS**

