Locating Hidden Tanks
Homeowners are often unaware of the presence of old heating oil tanks.
They may have used natural gas, propane or electricity to heat the house as long as they have lived there. The fill and vent pipes of the old underground oil tank may have rusted away, been removed, or been obscured by landscaping. Additions may have been built over the oil tank.
In the 1940s and 1950s, fuel oil and kerosene became a common source for heat. Underground storage tanks (USTs)were often buried beside the house. The life expectancy of these tanks is approximately 20 to 30 years. Many underground oil tanks have leaked for years while still in use. Often water enters a leaking tank and fouls the heating system.
An underground oil tank located beside a foundation wall may leak into basement areas. Soil cleanup will be required because of the health risks.
In response, a new tank might have been buried beside the original UST, or the leaking underground tank replaced with an aboveground oil tank. If natural gas was available the heating system might have been replaced. The old USTs were often left in the ground and still contain heating oil.
Clues to the presence of an underground oil tank.
- Home built in the 1960s or before.
- Natural gas service established years after the house was built.
- An aboveground storage tank is present (often installed to replace a leaking UST).
- Copper fuel lines in the basement or crawlspace (often cut off at the wall).
- Oil staining or odor in basement or crawlspace walls.
Cedar Rock also uses a metal detector and probing rod during site inspections to help find hidden USTs.
It is very common for there to be no signs that an underground heating oil tank has leaked. To protect your investment, please call us at 336 684-2734, or use our contact form to set up a site inspection.
When the tank has already been removed.
Remember, it is soil contamination that is the issue and not the leaking tank itself.
The pictures below detail the discovery of contaminated soil from an underground oil tank leak on a property where the tank had been removed. The active aboveground storage tank (AST) was almost certainly a replacement tank. No trace of an underground tank was detected during a metal detector sweep of the property. Before Cedar Rock's site inspection the presence of soil contamination caused by a UST was not suspected.
In this case, the buyer was not satisfied with purchasing a property with a Notice of Residual Petroleum, and required excavation of the contaminated soils. During the excavation the soil contamination was found to extend a significant distance in all directions.
Two pairs of copper fuel lines were observed in the the crawlspace, one set connected to the AST, and the other had been severed at the foundation wall, suggesting the past use of an underground oil tank.
Cedar Rock exposed the severed lines outside the foundation wall and the metal detector was used to trace the copper fuel lines to their end several feet out into the back yard within a slightly depressed area.
The soil was then sampled with a hand-auger. The bluish-gray discoloration is typical of contamination and the soil also had a strong petroleum odor. Note that the probing rod was pushed in easily to its full depth indicating that the soils had been disturbed.
Excavation of the contaminated soils. The discoloration due to petroleum contamination shows the approximate depth of the tank that was removed.