How long will heating oil fuel tanks last?

Today we will look at a topic we get asked frequently: “How long will my heating oil fuel tank last?”

The short answer is 20 years, but are we talking about an aboveground tank, or an underground tank?

Maryland Underground Oil Tank removal company

First, we’ll start with underground tanks.

The longevity of a UST (Underground storage tank) depends on many factors. First, what is the tank made of? Almost all residential UST’s are made of steel. Steel will rust. Many old UST’s that were installed decades ago are just bare steel buried in the ground with no coating or other protection on the outside. Thus, the tank will start to rust day 1 in the ground and will continue to rust and eventually develop holes. Another factor is the gauge of the tank’s steel. Some small tanks have a much thinner gauge of steel than larger tanks. So, that means the smaller thinner tanks will, generally speaking, not last as long as the larger tanks. However, it is not that simple.

Other underground heating oil tank factors to consider are:

  • Is there buried electric nearby the tank? – If there is buried electric lines near the tank the electrolysis can possibly corrode the tank faster.
  • Is there a high water table around the tank? – if a steel tank is frequently surrounded by water that obviously means the tank will rust more and degrade more
  • What type of soil surrounds the tank? – some soil types cause metal to degrade faster whether it be because they hold more moisture, or due to the actual soil composition itself.
  • What is the location of buried tank? – is the tank buried in a low lying area where standing water on the surface is common? This will mean you constantly have water around the fill pipe of the tank and causing it to degrade much faster. But also the water has to drain into the soil and go around the tank.

New tanks can still be installed in a residential application. Newer tanks can be coated with a basic waterproofing coating and there are several options to choose from, as well as upgraded tanks that can be purchased with other coatings. Anode bags can be attached to the tank to act as a sacrificial lamb to help protect the tank as well.

Now Let’s Talk About Above Ground Tanks

The most common tank we see is a singe wall steel 275 gallon AST (aboveground storage tank). The life expectancy of these tanks is 20 years. The steel is thin so if your tank is over 20 years old its time to get it replaced. Don’t delay, as a leak in an aboveground tank can be just as costly or even more costly to clean up than an underground tank leak.

These tanks tend to degrade from the inside out, while some exterior factors come into play, generally speaking, it does not matter if your tank is in the basement, outside, or in the garage. The tank will eventually leak, so its not “if” but “when”. The heating oil itself builds up sludge over the years which can hold moisture and cause the tank to degrade. This will lead to holes in the bottom of the tank that cause a slow, drip leak. These tanks do not “burst”, but slowly drip in the bottom where no one will notice until you either smell oil in the basement or you have dead vegetation outside where someone will notice. However, by then the damage has been done and there will be a cleanup process involved with soil remediation.

For new tanks we install, the basic tank outlined above has a 10-year warranty, is steel single-walled, and can hold 275 gallons. Upgraded tanks are available with special coatings, double bottoms, double walls, and longer warranty options. Tanks are also available in other sizes both larger and smaller. The longest warranty tank on the market is 30 years, so for a relatively small additional cost above a standard tank, you can get an additional 20 years of warranty. Some tanks even come with insurance.

So what have we learned today?


Basic rule of thumb – if you don’t know exactly how old the tank is, but it’s likely over 20 years old, its time to replace the tank regardless of whether you think its leaking or not. No one ever knows if a UST is leaking or not until it is removed and the soil properly tested. For AST’s, don’t wait just to save a few bucks, get the tank replaced now. Call GreenTRAX and we can help you with all of these problems.

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