Why is an Oil Tank a concern when Buying a house?

Oil tanks have a finite life span, they rust and they leak.  Did you know the propane tank for your BBQ grill only has a 15-year lifespan?   If you own your BBQ grill propane tank and take it to a home center to get refilled they will not refill tanks older than 15 years.

Not shocking, things get old, what is shocking, and mostly to your bank account, is the cost of cleaning up an oil tank leak.   Ever paint and spill paint? You have to clean the paint before it dries or it is too hard to clean up, just as with a stain on your clothes.  Think of that with an oil tank leak. When an oil tank leaks it tends to leak until there is no more liquid left in the tank.  A hole in the bottom of the tank can keep leaking, while slow, it can keep leaking forever.  If there is a hole in the top of the oil tank, either cut out to fill the oil tank or a hole from rust, this will allow the rain or water to fill the hole and the liquid from the oil tank to spill over the top of the oil tank and run down the sides.

Visualize this, go to your refrigerator pop a pin in a container of milk or orange juice, and walk away.  Come back and you got a big mess.  So when oil leaks you have to excavate soils that have oil impact, gravity pulls the oil down, many times deeper than the foundation of the dwelling requiring structural supports of the dwelling foundation to allow the excavation to be safely advanced DEEPER than the existing foundation.    If it sounds like I am speaking a foreign language, understand this to structurally support a foundation, you need engineering plans, permits, and typical helical piers to support the foundation.  Typical costs?  $11,000 to $20,000.00 on average.  That doesn't include soil excavation, disposal, testing, etc., that is just to dig safely.

The following is from a listing for a home for sale:

Please note, property may have an underground oil tank. No testing has been completed, the seller will not test or allow testing before settlement. Come see this 4 bedroom, 2 full bath home. The home offers a living room, eat-in kitchen, dining room, and family room. The home has a full basement. Located close to local amenities! Home will not be on the market long. Schedule your showing today! The property is being sold As-Is condition. Buyer is responsible for all certifications. The seller never occupied. Neither the seller or listing agent make any representation as to the accuracy of any information contained herein. Buyer must conduct their own due diligence.

Yes, you read correctly, the property has an oil tank and the buyer can't test it.  The buyer won't allow testing because the buyer doesn't want to know if the oil tank is leaking.  Leaking oil tanks cost money to fix and buyers will not proceed with the purchase when there is an unknown liability regarding cleanup of the oil tank leak.  Unfortunately, there is no standard pricing for oil tank leak cleanups.   It's not like a pizza. Looking back over the last 30 days from the date of this writing we have completed oil tank projects that required no remediation, $8,950.00 of remediation, $42,731.00 of remediation, one was $19,564.00 another one was around $13,000.00, a small AST leak was $5,672.00.  The cost to remediate and oil tank leak varies, but to even determine and diagnose the extent of contamination you have to spend several thousand dollars to define the area.   

Do you think digging up the oil that leaked below this garage was inexpensive?

 The reason there is no home in this photo is that it had to be demolished to remove the contaminated soil from the underground oil tank leaking. 

With unknown costs for cleanup, you can see why a seller doesn't want to deal with an oil tank.  You can also see how dangerous it is for a buyer to ignore evaluating a property for a tank Tank Sweep, testing a known tank Tank Testing.