When is an AST a UST?

UST is a tank that has 10% or more of the tank volume below grade, i.e., not visible.   The photo below is of a 1000-gallon UST because the tank could not be visually inspected.

An AST (Aboveground Storage Tank) is one where you can inspect 100% of the tank.  The tank below is an example of an AST.

The photo below is a trick photo.  The tank was buried under a set of concrete stairs, so technically the tank was aboveground, but could not be visually inspected so it was an underground tank.

Questions on your oil tank?  Give Curren a call, we are consultants and can discuss your situation and plan of action.