The bottom line:

Average: 10-15 Years

At 20 years – the risk of leaking increases significantly

BUT – there are many factors that can decrease the lifespan of an underground storage tank significantly.

underground oil tank

Factors that affect the lifespan of an underground oil tank:

  • Exposure of the tank fill pipe to water entry or runoff

    • Particularly if the fill pipe is installed flush with the ground rather than raised. In this situation, rainwater and snow will sit against the pipe for long periods, increasing the likelihood of corrosion and leakage.
  • Damage to the tank during installation

    • If the tank was scraped in any way during its installation, it could create a weak, thinner spot that is more prone to leaks.
  • Damage to tank & piping from surface activity

    • If the tank is buried below a driveway, near the street, or in any area that experiences traffic from vehicles and/or heavy machinery, the added pressure to the tank could cause damage and, therefore, leakage.
  • Damage to tank, piping or vents from vehicles or machinery

    • If vehicles, mowers, tractors, etc. come in contact with any of the pipes or vents near the surface, it could cause damage to the tank that might not be visible from the surface, increasing the potential for leaks.
  • Corrosive soils

    • Some soils are much harder on steel, copper lines and brass fittings than others, and can quickly cause damage to the tank and hardware, resulting in leakage at many different points.
  • Conductive soils

    • Clay soils and tightly packed, moist soils can be very conductive and carry electrical currents to the tank, increasing corrosion rates as well as the likelihood of leaks. This is especially a risk in urban areas and around electrical grounding and/or wiring faults.
  • Amount of groundwater in the soil

    • This is the primary culprit for underground oil tank leaks. The more water present in the soil, the greater the rate of corrosion to the steel tank, copper lines and brass fittings. If there is poor drainage in the area around the tank, if there is frequent rain or snow, or if the tank is near a river or body of water, there is a significant risk of leakage due to corrosion.
  • Defective tanks and/or welds

    • If the tank was manufactured with defects or if the welds were low quality, incomplete or incorrect, the likelihood of leakage is greatly increased.
  • Wrong type of tank

    • There are many cases in which the underground oil tank installers had installed tanks that were never meant to be buried. Smaller tanks, like 250g or 275g tanks, are not rated for underground installation. The steel is far too thin and weak to resist the pressure of the surrounding soil and water in the ground and will therefore leak significantly faster than others.

TIPS To minimize the risks of a leaking underground oil tank

  • Test your underground oil tank for the presence of water at least once per year.  Even if the tank is relatively new and installed properly, this is the best practice to detect a leak. If water is found in the tank, it should be pumped out immediately, as water corrodes the steel from the inside out and increases the likelihood of a leak.
  • Make sure roof spillage and surface runoff is directed away from the location of the buried oil tank.  
  • Because the back-fill around the buried oil tank will normally be less dense than surrounding soils, surface runoff or roof drainage will more readily seep into the area around the buried tank. This not only adds to the corrosion of the tank but may also increase the likelihood of water finding its way into the foundation and/or basement if the tank is close to the house.

It’s always best to have your underground oil tank removed before it gets too old or if it’s buried in corrosive soil or if it’s installed in an area that’s exposed to a lot of water.

Tank with Backhoe

Why should you remove your underground storage tank (UST) from your home or commercial building?

Many older homes and buildings have underground tanks used to store oil for heating.  All underground storage tanks have a limited lifespan and will corrode and leak eventually depending upon the age of the tank and the conditions of the ground where the tank is buried.  Whether you intend on selling a home or a commercial property almost all mortgage companies now require that any underground tanks on the property are removed, and if the tank is found to have leaked that all the contaminated soil is excavated and disposed of, eliminating any future liability for the new owner.

 The process of removing an underground storage tank is fairly straightforward:

  • The municipal permits are obtained by a fully licensed NJDEP UST closure contractor
  • A utility mark out is called in by the contractor,
  • The contractor mobilizes to the site with their crew and equipment
  • The contractor neatly saw cuts the sidewalk, driveway or parking lot when necessary to expose the top of the tank or just simply dig in the grass or yard.
  • Leftover tank contents are pumped out by a vac truck when needed or just placed into 55-gallon drums when just a small amount
  • The tank is cut open and the sludge at the bottom is cleaned out and placed into a 55-gallon drum
  • The tank is removed from the excavation and place on top of the ground next to the hole
  • The township inspector arrives to inspect the tank to make sure there are no holes and the soil where the tank had been to make sure there is no sign of oil and determines if the inspection is passed or failed
  • Passing inspection – the contractor fills the excavation with certified clean fill and restores the lawn, sidewalk, driveway or parking lot.
  • Failing inspection – a DEP Case is opened, a subsurface evaluator or LSRP is brought out to the site, makes a determination of how much soil needs to be excavated and stockpiled onto plastic and takes soil samples from the sides and bottom of the hole.  If the results come back clean, the project will finish by loading out the stockpiled soil into a truck to be disposed of at a state-approved facility and finishing by restoring the lawn, sidewalk, driveway or parking lot.

 As you can see, a failed inspection is a much more complicated proposition than passing is and is quite a bit more costly too.  Sometimes when a tank has been left in the ground too long and has corroded it can leak for years which can result in a large quantity of soil that needs to be disposed of or leaking below the foundation of the home or building, or onto a neighboring property or into the groundwater.  Any of these scenarios can add up some costly bills.

Soil Remediation

 Removing an underground tank that is on your property before it’s too late can eliminate a potentially very expensive liability while simultaneously increasing your property’s value, allowing you to sell quicker and easier than a competitive property that still has their tank in the ground. 

SER Scranton UST Removal

 When is a good time to remove an underground storage tank?

 Anytime you can get the tank out of the ground before it corrodes and leaks into the soil or groundwater is the best time to remove the tank.  If your furnace or boiler fueled by heating oil is at the end of its life span, that too is the perfect time to switch to natural gas when possible or add an above-ground tank outside on a concrete pad or inside in the basement.  Removing the tank and eliminating liability and an expensive clean-up is in your best financial interest, always.