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I’m looking to buy a house. We know there is one 550 gallon oil tank in the front right yard. There are two unused oil fuel lines that were found in the basement near the heating, and one vent pipe found on the front right side of the house, no fill pipe was found. Oil isn’t used in the house anymore. The deck area of the house couldn’t be checked because the deck wasn’t removed. Based on what was found - the pipes... - how likely is it that there is another tank in the back of the house?