This article explains how water gets into buried oil tanks or underground oil storage tanks. We explain how to test for or visually check for water in a buried or above-ground oil storage tank, and how to get water out of an oil tank. Extensive free un-biased oil storage tank inspection and testing advice for property buyers and owners is provided at this website.
This article series explains the problems caused by water accumulation in oil tanks, how water gets into the oil tank, how to measure water in the oil tank, how to remove water from oil storage tanks regardless
of whether the oil tank is indoors, outdoors above ground, or buried, and how to prevent water from getting into an oil storage tank.
This website provides detailed information about underground (buried) oil storage tanks (USTs),
aboveground oil storage tanks (ASTs), above ground fuel storage tanks, reporting and cleaning up oil tank leaks, and choosing among oil tank leak testing methods.
The buried oil tank illustration (above) is provided courtesy of Carson Dunlop Associates.
How Does Water Get Inside a Buried Heating Oil Storage Tank
Water enters a buried oil storage tank by condensation: as temperatures vary moisture-containing air may be drawn into and then out
of an oil tank.
Air leaves the tank as oil is consumed; air enters and leaves the oil tank through the oil tank vent. Moist air entering the tank
from outside can bring water which, on entering the cooler tank interior, condenses out of vapor form into water droplets which can, over time
Water can enter an underground oil tank through the filler pipe: from roof spillage onto the tank or filler top (particularly and obviously if the filler cap is left off),
or from ground or surface runoff entering the oil storage tank (particularly and obviously if the filler cap is near, at, or below ground surface level).
Leaving off an outside oil tank filler cap for a few days is not itself a likely source of a problem unless the filler
was exposed to heavy rain, roof runoff spillage onto the open filler pipe, or surface runoff entering the tank
(such as for a filler pipe flush with the ground).
Water leaks into a buried oil tank from an actual tank perforation that admits ground water, or from a bad plumbing fitting on the tank.
When oil levels in the tank is below an oil tank perforation or a leak in oil tank piping, it is possible for ground water to leak into a buried oil tank just heating oil may leak out of the oil tank when it is filled above the perforation or leak point.
Water leaks into the buried oil tank from a faulty filler cap gasket around the oil tank filler pipe plug, especially at installations whose oil tank filler pipe is located in a box whose top is flush with the ground surface (see our photo, left).
Water leaks into the buried oil tank from an oil tank vent pipe that is missing a cap to protect against rainwater or roof runoff spillage into the tank, especially if the vent (or filler pipe) are located under the roof's drip-line.
Water leaks into a buried oil storage tank from leaky oil piping fittings. R.W. Beckett recommends that [Quoting]
All pipe fittings must be tightened securely and have the threads sealed with a resilient compound that can endure the environmental variables in temperature. Any loose or poorly sealed [oil tank fuel piping, fill, or vent piping] joints can permit ground water to infiltrate the [oil] storage tank.
Water is delivered to the oil tank along with the heating oil fuel: This is not common, but it is possible to get a delivery of "bad" heating oil that is water contaminated,
especially if the oil truck happens to fill-up at the oil storage depot when an oil barge is
unloading oil since during that operation water which is normally kept in the bottom of oil depot
storage tanks may be stirred-up.
Most oil companies know to avoid this problem and some also have water
filters installed at their oil trucks. No oil company is going to admit that they picked up and delivered
water-contaminated oil to your home so don't waste time asking them if they are guilty of this crime.
R.W. Beckett referred to this [quoting] "possible but rare contributor due to storage and maintenance practices in the [heating oil] distribution system. Large bulk [oil storage] tanks must be checked for condensation accumulation and bled periodically.
If this is not done conscientiously, then it is possible for water to be drawn out with the oil when the stocks are extremely low or when the bulk storage is filled and the water is forced into temporary suspension.
Fortunately, [the heating oil sales and delivery] industry has implemented effective maintenance measures and this has been virtually eliminated. However, if water and sludge are found in a tank that does not have a leak, then it must be thoroughly pumped out, cleaned, and treated with a chemical additive that disperses water, sludge and neutralizes bacterial growth."
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"Preventing Water from Entering the [oil heating] Fuel System", Technical Information Bulletin, 10/15/1990, R.W. Beckett Corporation, 38251 Center Ridge Road, PO Box 1289, Elyria OH 44036, Tel: 440-327-1060, Email: email@example.com
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson, Dunlop & Associates Ltd., Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
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
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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