A fueling system is considered underground if ____% or more is below ground.

A fueling system is considered underground if ____% or more is below ground.

• A. 5%
• B. 20%
• C. 10%
• D. 50%

Answer: (C)

If part of a fueling system sits below ground, the defining line is how much of it is buried. The standard threshold is 10% or more below ground for a tank to be considered underground. This minimum amount being buried is enough to trigger underground storage tank rules and necessary protections, like leak prevention and corrosion monitoring. So 10% is the critical cut-off: at least that much below ground makes the system underground, and anything greater also qualifies.

If part of a fueling system sits below ground, the defining line is how much of it is buried. The standard threshold is 10% or more below ground for a tank to be considered underground. This minimum amount being buried is enough to trigger underground storage tank rules and necessary protections, like leak prevention and corrosion monitoring. So 10% is the critical cut-off: at least that much below ground makes the system underground, and anything greater also qualifies.