Vent pipes often remain at the site long after the tank is out of use.
How do I know if I have a tank?
Any house built prior to 1975 is suspected to having or having had an underground oil tank. Older "historic" homes (built pre-1950) may have been converted from a coal furnace to an oil furnace in the 1950's when fuel oil became readily available.
Underground oil tanks are found at almost all properties where the house was built in the 1950's and early 1960's. Natural gas lines served a very limited portion of Wilmington and other heating options were virtually non-existent. In the late 1960's alternative heating sources were becoming available.
The following is a list of Wilmington neighborhoodsthat typically have underground oil tanks: Forest Hills, Oleander South, Glen Meade, Brookwood, Lincoln Forest, Pine Valley, Long Leaf Hills, Devon Park, Hanover Heights, Sunset Park, neighborhoods north of Oleander Drive and south of the university, neighborhoods in the vicinity of Cape Fear Hospital, neighborhoods north of Market Street near 23rd Street (Princess Place, Chestnut Heights, Willowdale, etc. ), neighborhoods around Greenfield Lake, and other houses built prior to 1975.
There are several other clues that may tell you if you have or had an underground oil tank on your property. We will start with more obvious clues and work toward the less obvious ones. You may want to have your home inspected or PES can search your property for an underground oil tank.
Oil tank fill pipes are either a flip top or a galvanized collar with a brass cap (pictured).
1) Fill pipe: This is a 2 inch galvanized steel pipe that has either a lockable flip cap or a brass cap that screws into a galvanized steel collar. These pipes may be flush with the ground or they may stick up several inches. Bushes and landscaping may conceal fill pipes of out of use oil tanks.
Fill pipes are typically with in twelve feet of the house foundation and go directly down into the tank. If an addition has been added to the house, it is possible that an out of use fill pipe could be located under the addition.
Because fill pipes commonly stick up above the ground surface, many property owners have removed or cut off these pipes below the ground surface when the tank is taken out-of-use. Cut off fill pipes are rarely sealed properly and usually allow water to enter the tank.
2) Vent pipe: This is a 1 to 2 inch galvanized pipe that has a mushroom shaped cap on the open end (top) of the pipe. (Occasionally, the pipe may simply have series of galvanized steel elbows that turn the pipe opening downward.)
Usually the vent pipe is plumbed away from the tank and set next to the house foundation. (Most vent pipes do not identify the exact location of an underground tank.)
Vent pipes typically stick up 6 inches to a foot and a half above the ground surface. Vent pipes were not always installed on underground tanks. In rare occasions the vent pipe is constructed of PVC.
3) An old oil furnace or parts of an oil furnace in or under the house: Glass and metal oil filter housings are commonly left usually attached to the fuel supply lines (copper) described below.
4) Two Copper Tubing Lines (¼ inch) in the crawl space or basement: After the tank is taken out of service, the old fuel supply lines are often left under the house even if the old oil furnace is removed.
Inspectors: Please note where these copper lines go under the foundation. This will help to focus the search for the underground tank.
5) A furnace chimney: Many 1950's houses have a small (1 foot by 1 foot) furnace chimney. Occasionally, a furnace chimney is routed into a fire place chimney. If so, there will be two flews coming out of the top of the brick chimney. Examine the top of your chimney.
Unfortunately, some out-of-use furnace chimneys may have been removed during a roof modification. Clues indicating that an earlier furnace chimney may have been removed may be discovered in the attic.
Note the furnace chimney.
6) Your house is in an oil tank neighborhood: See our partial list at the top of this page. You may also inquire with your neighbors to see if they have or had an oil tank. The presence of furnace chimneys is another easy to observe clue.
7) Your house was built prior to 1975: This is reason enough to be concerned and start asking questions. Houses built between 1945 and 1965 are almost guaranteed to have been heated with oil at some point in their history.
PES can conduct a tank search on your property that includes a metal detector survey.
Usually an above ground tank was proceeded by an underground oil tank that had a problem.