Underground area means an underground room, such as a basement, cellar, shaft or vault, providing enough space for physical inspection of the exterior of the tank situated on or above the surface of the floor.
Underground storage means storage of hazardous liquid in a subsurface stratum or formation of the earth.
Underground tank means a device meeting the definition of tank whose entire surface area is totally below the surface of and covered by the ground.
Ground water means water below the land surface in a zone of saturation.
Underground facility means any item which shall be buried or placed below ground for use in connection with the storage or conveyance of water, sewage, electronic, telephone or telegraphic communications, electric energy, oil, gas or other substances, and shall include, but not be limited to pipes, sewers, conduits, cables, valves, lines, wires, manholes, attachments and those portions of poles and their attachments below ground.