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.
SIGNS OF BURIED OIL TANKS- A Photo Guide to Visual Clues for Finding Buried Oil Storage Tanks - Part 1, Outdoor Clues
How 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
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 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.
Depressions near a building suggesting recent excavation, particularly if the depression is outside a wall where it would have been logical to install a buried tank, such as at a building foundation near the location of indoor current or previously installed oil-fired heating equipment.
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.
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.
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.
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.
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.
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 Fuel Storage] Tank Corrosion Study, U.S. EPA report on gasoline and oil tank corrosion, James H. Pim, P.E., John M. Searing, Suffolk County DOHS, 15 Horseblock Place, Farmingville Long Island, NY 11728, November 1988, for the Office of Underground Storage Tanks, U.S. EPA. ATTN: David O'Brien. The report presents a study of 500 underground storage tanks spanning 24 February 1987 and September 1 1988 and summarizes earlier reports on this same study. Tank sizes ranged from 175 gallons to 50,000 gallons, and oil tank ages ranged from two years to 70 years old. All 500 oil storage tanks were constructed of welded steel, and 12 other tanks that were other than plain steel were also examined. Summary [with minor edits for clarity by DJF]
 Thanks to Arlene Puentes for for technical edits on oil tank leak advice- 12/2005. Arlene Puentes is a licensed home inspector, educator, and building failures researcher in Kingston, NY.
 "A Case Study of a Large Scale Precision [oil or fuel] Tank Testing Program", Diane H. Heck, Tetra Tech Richardson, Newark, Delaware, web search 4/27/12, original source: http://info.ngwa.org/GWOL/pdf/870143411.PDF, copy on file as /heating/OIl Tanks UST/Tank_Test_Heck_870143411.pdf
 Fuel Oil and Oil Heat Magazine, August 1985 p.18. Fuel Oil & Oil Heating Magazine, 3621 Hill Rd., Parsippany, NJ 07054, 973-331-9545
 Standards of the National Board of Fire Underwriters, as referenced by "Domestic and Commercial Oil Burners,", Charles H. Burkhardt, 1961, 3rd Ed., McGraw Hill Book Company, p. 172
 NFPA - the National Fire Protection Association can be found online at www.nfpa.org
 "The Interim Prohibition Guidance for Design and Installation of Underground Oil Storage Tanks", U.S. EPA, EPA/530-SW-85203, Office of Underground Storage Tanks, Washington D.C.
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 US EPA "How do you Properly Close a UST?" is summarized at epa.gov/OUST/fsprevnt.htm These details for temporary and permanent closing of underground oil storage tanks are provided by the US EPA as well.
 "How do you choose the right tank testing method?", Cynthia Johnson, Fuel Oil & Oil Heat Magazine, November 1995
 National Association of Oil Heat Service Managers, PO Box 380, Elmwood Park, NJ 07407
 "Homeowners Guide to Fuel Storage," Agway Energy Products, Verbank, NY, November 1990
 "Causes of Underground Corrosion", Harco Corporation, Paper HC-36, Median OH
ABOVE GROUND OIL TANK (AST) GUIDE - "Visual Inspection of Above Ground Residential Heating Oil Storage Tanks - ASTs" Advanced Home Inspection Methodology - Developing your X-Ray Vision
A Promotion Theory for Forensic Observation of Residential Construction. Discussion of methods to accumulate clues to enable
the detection of hard-to-find defects on buildings or other complex systems.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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