Above Ground Heating Oil Tank

Almost all houses existing before the mid 1960s used heating oil which was stored in either an underground or above ground tank. An above ground storage tank (AST) was usually located in the crawlspace, basement or against a side or back wall of a house. In many cases, an above ground tank was later installed to replace a leaking underground storage tank (UST). Importantly, an AST can be more of a liability than an UST.

Let us tell you why...

  • Compared to releases of heating oil from underground tanks stricter regulations apply to above ground tank releases and the cleanup and assessment of all impacted soil and groundwater to State standards is more expensive.
  • Because of where above ground tanks are usually located, leakage typically extends beneath the residential structure, limiting access for the removal of impacted soil and requiring more expensive excavation by hand.
  • It is harder to get State clearance for above ground tank releases as a result of more limited access and stricter cleanup requirements. An AST release will remain as an open file for as long as contamination exceeding State standards exists which can influence lenders.

However, the most significant difference between AST and UST releases is:


The cost for soil cleanup from an AST release is the sole responsibility of the property owner.

What you should consider ...

  • Buyers should have an inspection for heating oil contamination for any house built before the mid 1960s.
  • Request an inspection as soon as a contract to purchase is drawn.
  • Include an escape clause in the offer to purchase in case contaminated soil is discovered.

Remember, most homes built before the mid 1960s used a heating oil storage tank. Do not assume that the removal of the tank included the removal of impacted soil. Have the soils inspected.

One thing to note is that a partially buried tank may or may not be deemed to be an UST. This determination can only be made by State officers and is another reason why a proper site inspection is essential. One photo in the slide show shows a tank that the State deemed to be an UST. This decision saved the responsible party a great deal of money.

Above Ground Storage Tank - Two Cases

The following photos illustrate two aspects of above ground tanks. The left photo shows a leaking AST which has been leaking for a long time. The property owner's solution to his leaking AST was to place a plastic sheet underneath the AST and place the collected oil in plastic trash bags. His efforts were futile and leakage continued eventually extending several feet beneath the house, requiring expensive hand excavation. The AST and contents should have been removed for proper off-site disposal as soon as the leak was discovered.

Leaking AST with poor attempt to contain oil Scene of hand excavation in crawl space

In the photo to the right you can see an excavation pit in the crawlspace of a house. When the house was bought the buyer removed the AST but chose not to inspect the underlying soil. Two years later the next buyer, when informed of the former AST, did have the soils inspected and discovered significant contamination. The failure to inspect the soils cost $20,000 of the original buyer's profit to cleanup the soils to acceptable standards!