Photograph of sketch of parts of a buried oil tank How to Find Underground or Buried Oil Tanks - outdoor clues

  • BURIED OIL TANK, SIGNS OF - CONTENTS: These outdoor visual clues help find buried oil tanks by visual inspection of the site & building. Photo guide to visual clues suggesting presence of buried oil storage tanks at a property
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Spot these signs of a buried oil tank:

This is a photo guide to visual clues spotted first outdoors and second indoors to help detect and locate abandoned or buried oil tanks or the detection of evidence that an underground (or even an above ground) oil tank is or was in use at a property.

The article and photographs used to show the reader ways to find buried oil tanks include examples of clues leading to the discovery of "nearly hidden" buried or underground oil tanks which were found at residential properties and which avoided very costly surprises later for the new owner.

Underground oil storage tanks, or UST's, whether still present or previously removed, involve a risk of costly oil leaks and soil contamination which may need to be addressed. Here are some investigation methods that any home buyer, owner, or home inspector can apply to reduce these risks by looking for evidence that a buried oil tank is or was at a property.

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Photo Guide to Visual Clues for Finding Buried Oil Storage Tanks - Part 1, Outdoor Clues

Buried oil tank piping (C) M Cramer D FriedmanHow to find buried oil tanks: Evidence that a buried fuel storage tank exists at a property may be direct and visually obvious, or the evidence may be subtle. Mark Cramer's photo (left) shows a pair of painted-over copper pipes penetrating a building foundation wall close to ground level - a strong suggestion of a buried oil tank at this property.

Often a series of small observations, individually not apparently very important, can add up to an increased probability that a buried fuel storage tank is or was at a property.

While environmental investigators and oil tank test companies may use magnetic scanners or even ground scanning radar to locate buried steel tanks, an astute visual inspection can often discover the presence or probable presence of a buried fuel storage tank at a property, thus suggesting that further testing is definitely in order.

Here are some clues to the possible current or past presence of a buried tank at a property.

Photographs of Outdoor Evidence of Buried Oil Tanks

Pipe indicates buried oil tank Pipe indicates buried oil tank

Visible oil tank fill or vent pipes protruding from the ground or flush with the ground anywhere on a property.

Oil fill pipes may be directly over a tank, near a tank, close to a building wall, or located at a considerable distance from the building and from the tank as well. Our photo (above left) shows an oil fill pipe located nearly 25 feet from a building exterior wall.

The combination of distance from the building and the type and size of building (large antique barn at an estate) hint that this may be a large buried oil tank.

Mark Cramer's photo (above right) shows an oil tank fill pipe cap (rust-colored round object closer to the building wall) and an oil tank vent pipe cap (silver colored object) . Placing the oil tank vent pipe cap at ground level was probably a cosmetic decision by the homeowner, but if that area of missing leaves marks a spill line from roof runoff, we're also asking for a problem with water in the oil tank at this home.

Curbside oil fill pipe
Curbside oil fill pipes: Look for remote & curbside oil filler pipes: In some neighborhoods we've observed oil fill valves located in a curb box at the street for oil tanks which were buried more than 75 feet away.

The vent pipe for an oil tank filled in this manner will probably be nowhere near the curb and may be not even too close to the oil tank. At the property served by this curbside oil tank filler, the tank was buried uphill near the home and the tank vent pipe appeared near the home's foundation wall.

Dead grass marks oil fill

Areas of dead grass or plantings
in a small spot where a buried or previous fuel tank fill pipe may have been installed - from spillage of fuel.

At one site this clue led to the discovery that the tank "removal" had consisted of nothing more than the unscrewing and removal of the fill and vent pipes from the leaky oil tank.

Buried oil tank at a farm

Age and type of property: often older buildings, farms, and commercial buildings will have had a buried tank installed even if more recently the fuel has been converted from oil to gas. Our photo shows a red pump control in front of the mowing tractor to the right of this barn.

The pump served a buried diesel fuel tank used for farm equipment. At other properties where farm buildings were present buried diesel fuel tanks have been found with no initial evidence other than the age of the property and the probability that such tanks would have often been present close to farm buildings.

Sites distant from a village or town are more likely to have required a larger onsite fuel storage facility. Farms may also have had fuel oil stored for diesel tractors or other farming equipment, so remember to look for clues of buried oil tanks at a central location near old farm buildings. Even if an old indoor oil tank is in view at an old property, don't assume that a still-older tank is not also buried nearby.

Buried oil tank piping

Oil Fill and Vent Piping Location:
In the confusing photo at left, we see an oil fill and vent pipe close to the building wall. We don't know if those pipes serve an indoor tank or a buried outdoor tank until we look further. But my black notepad in the photo lower left corner marks another vertical standpipe which could mark the end of a large underground oil storage tank.

If the oil tank fill pipe is a straight line down from above ground into the tank, and if the tank is buried close to a building wall, measure the distance from the center of the fill pipe to the building wall.

If the distance is small, perhaps 20" or less, we suspect that an indoor-tank, not rated for outdoor use, may be buried there. The typical dimensions of a 250 or 275 gallon oil storage tank, usually oval in shape, are 5' long x 4' high (excluding legs or other support.)

These oil tanks are roughly 27" in width. The threaded tappings used to mount fill and vent pipes are located in the center of the width of the fuel or heating oil storage tank.

A storage tank buried close to a building wall and with a fill pipe going straight down into the tank, would display a filler pipe which is as little as 14" from the building wall (measured from the outside of the wall to the center of the filler pipe). So if a filler pipe is located close to the wall and passes straight down into the tank, the distance can indicate the probable tank cross section or width and can indicate an indoor tank which has been improperly installed outside.

Vent pipe for oil tank

Unexplained oil tank vent pipes may be found at building foundation walls nowhere near currently-installed heating equipment or oil tanks.

Be sure to investigate pipes like the one in our photo at left. It may lead to a buried oil tank or to an oil tank which has been abandoned in a building crawl space.

Oil vent pipe

Amateur oil piping installations may be found still in place. Is a buried oil tank still present or not? This undersized oil filler line indicates either that the installation is quite old or that the plumbing was not done by a professional.

Similarly, you may trace oil piping to an old "lost" oil tank in an inaccessible or hidden crawl space or even a basement closet.

Follow backwards oil fill or vent piping or oil supply piping between to oil tank from he oil fired equipment it supplied.


Continue reading at OIL TANK FAILURE RATES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

If your oil tank is leaking see OIL TANK LEAK ADVICE.


Or see these

Buried Oil Tank Location Articles

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