Photograph of  Half-Buried Indoor Oil Storage Tank Used Outside below a ready to collapse deck Heating Oil Storage Tank Inspection Procedure
Checklist of common heating oil storage tank defects for both ASTs & USTs

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

This fuel oil storage tank article describes common defects & problems found at above ground and buried oil storage tanks for both above ground oil storage tanks (ASTs) and underground or buried oil storage tanks (USTs).

We discuss problems with oil tank contamination by water or dirt, oil tank location and clearances, oil tank rusting and leaks, oil tank leak testing, oil tank piping, oil tank support and protection from damage, oil piping safety valves, & how to avoid trouble with oil tanks that are exposed to cold weather.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Finding & Reporting Oil Tank Defects by Visual Inspection

Sketch of distance fromn oil tank to oil burner (C) Carson Dunlop AssociatesThis document describes and provides home inspection report language for defects in heating oil tanks, oil piping, and other oil storage tank installation defects that can be found by visual inspection for both above ground storage tanks (ASTs) and underground oil storage tanks (USTs).

[Click to enlarge any image]

Beyond the costly problem of leaky heating oil tanks, this document lists other important safety or oil-fired equipment operational defects in home and light commercial heating oil storage and piping systems.

This sample home inspection report language may assist home owners or home buyers in understanding risks associated with both buried and above ground oil or other fuel storage tanks at their property.

The oil tank and oil piping inspection report language explains the need for action and indicates where more information can be obtained. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.



Oil tank defect photographs are at Visual Inspection of Oil Storage Tanks.

NOTICE: while example report language is provided here, reproduction of this or any of our web pages or their contents online at other websites or in printed documents for sale is prohibited. Readers are welcome to use the text directly in home inspection reports, with citation of the website source.

OIL TANK IN GARAGE - Oil Tank in Garage - warning

The tank is in the garage. Caution: Don't hit the tank with your car - a leak could involve a costly cleanup. Some municipalities require protective caging or barriers be built around the tank to avoid this hazard.

OIL TANK NEAR WATER - Oil Tank - nearby waterway, risks & code HAZMAT

Photograph of  an oil tank floating up out of the ground after area flooding

Nearby waterway or Adjacent property
(estimated within ___') formed by the stream (or other body of water) would be contaminated should this tank leak or fall over.

The OIL TANK at this location without protection is in possible violation of NYS Building Code 1002.2b and 1002.4c "Above ground tanks shall be provided with means to prevent accidental discharge from spreading to waterways,

OIL TANK TOO CLOSE TO FURNACE - or Boiler or Water Heater - Oil Tank Clearance Distances from Heating Equipment

Technical Safety Recommendation: The oil tank may be located closer than recommended distance from the boiler. You should discuss this question with your heating service person.

Sketch of distance fromn oil tank to oil burner (C) Carson Dunlop Associates

Our sketch at above left, courtesy of Carson Dunlop, shows the typical ten foot clearance recommended between the closest point of the oil tank and the closest point of an oil burner.

OIL TANK SAFETY CLEARANCE from heating equipment - Building and Fire Code Citations

Oil tank clearance from furnace or boiler (C) Daniel Friedman - Audel


OIL STORAGE TANK EXPOSED TO WEATHER - Outside Oil Tank, (not buried) Exposed to Weather

Photograph of  an indoor oil tank used outside and exposed to roof spillage Photo  © 2010 Arlene Puentes

Caution: As this home heating oil tank is outside, it is exposed to water entry either through roof spillage onto the tank and splashing into the the filler or vent pipes.

Water may also accumulate in this outside oil storage tank by condensation due to temperature changes.

Water in heating oil can cause loss of heat if it reaches the oil filter or oil burner. Water in heating oil tanks also often leads to internal corrosion and leaks in the oil storage tank itself, possibly ending in a costly oil leak or spill.


We recommend:

  1. Keep roof spillage off of the tank top by adding a roof or enclosure over or around the tank;
  2. Test the oil tank for water presence and remove any excessive water;
  3. Use a fuel oil additive such as 4 in 1 Hot(TM) to assist in removing moisture from the oil. Photograph courtesy of Arlene Puentes]

This is a new heating oil tank (rated for indoor use according to its UL label) located outdoors. If you click-on and enlarge Ms. Puentes' photograph of this oil tank you will see that its top is wet from roof spillage and splash and that water runs down the side of the tank.

The fill and vent piping on this tank appear intact from the photo but the tank and its heating oil contents have other risks which we discuss in this oil tank inspection report sample text section.

Outdoor oil tank exposed to roof spillageWhen an indoor-use heating oil tank is located outside it is exposed to water entry either through spillage (such as from a roof edge shown in this photo) onto the fill and vent pipes or by condensation due to temperature changes.

Water in the fuel oil or simple exposure of the oil to cold temperatures can lead to loss of heat and resultant damage to a building by several means:

Water in oil tanks also often leads to internal corrosion and leaks in the tank itself, regardless of the tank location, though buried tanks and indoor oil tanks are less prone to water accumulation due to in-tank condensation in response to temperature changes than a tank located above ground outside.

Oil storage tanks usually fail from rust perforation due to combination of water inside the tank with sulphur in the fuel oil. External rust, unless very heavy, isn't highly correlated with internal rust. A new tank, when required, may cost more $2000. installed, including removal of the old oil tank.

When an outdoor tank is exposed to these conditions and even for an indoor tank which we suspect has had a dose of water and sludge, we recommend regular use of a heating or fuel oil additive to absorb water and to help break up sludge. The best solution is to locate the tank indoors or to build a heated shelter over the outdoor tank.

How to Keep Water Out of Your Heating Oil Storage Tank and Avoid Loss of Heat

Details about preventing water from accumulating in oil storage tanks are at OIL TANK WATER PREVENTION. Excerpts are below.

Photograph of  an indoor oil tank used outside and exposed to roof spillage and water entry at the oil tank vent pipe (shown in photo) Photo  © 2010 Arlene Puentes

Buried oil tank schematic (C) Carson Dunlop Associates

BURIED OIL TANK - Found or Suspected at a Property

Pipe indicates buried oil tankOur full article detailing how to suspect and find buried oil tanks at properties can be read at BURIED OIL TANKS, FINDING.

Sample oil tank inspection report for buried oil tanks: A buried oil tank is installed and could not be inspected. Advice follows

The following articles provide details on what to do if you own or are buying a property that has or might have a buried oil tank or underground storage tank (UST) on the land.


OIL TANK SUPPORT - Oil Tank legs need masonry piers or tank support piers are out of level

"Oil Tank legs for this outdoor tank should be supported by level and sound masonry piers to reduce the probability of the oil tank feet sinking or tipping and causing the tank to tip over.

Tipping or falling outside above ground oil tanks risk a fire, heating oil spill, or a "loss-of-heat" hazard.

Photograph of  an indoor oil tank used outside and risking tipping over due to inadequate masonry piers  © 2010 Arlene Puentes

This repair/maintenance item should not be deferred. This is usually an inexpensive item to correct." [Photo courtesy of Arlene Puentes]

See OIL TANK SUPPORT for full details about proper support and protection for above ground oil storage tanks.

OIL TANK LEAKY/PATCHED - Oil Tank Leaky/Patched - replace soon

Leaky oil tank photo

"The oil tank is very likely to have to be replaced soon if not immediately - the tank was leaking and a "patch" has been strapped to the tank bottom.

Removing old tanks and installing are placement oil tank will involve significant expense.

WARNING: serious and costly oil tank spillage can occur at any moment, but especially when this oil storage tank is being filled."

OIL PIPING DEFECTS - Reporting Oil Piping Defects by Visual Inspection

Defects in oil fill or vent piping are much more serious than you may think. That little drip of oil onto the basement floor is just a clue - but when your heating equipment is running, air drawn into the oil line at that same leak point can lead poor or dirty oil burner operation, a dangerous puffback, or loss of heat and related building damage.

And defects in the oil fill and vent piping can lead to catastrophic indoor or outdoor oil spills (as we explain at OIL TANK PRESSURE).

Details about heating oil piping inspection and defects begin at OIL TANK PIPING & PIPING DEFECTS.

MISSING SAFETY CONTROLS & SWITCHES at the Oil Tank & Oil Burner: Electrical shutoff switches for heat and oil line shut off valves

Oil burner oil line switch (C) Daniel Friedman

Oil heating equipment safety controls are discussed in detail at FIRE SAFETY CONTROLS where we provide more information on oil heat equipment electrical switches and on the fusible-link oil supply piping valve, check valve, or related controls that help prevent pumping heating oil onto a building fire as well as avoiding other oil piping problems.

Reader Question: is it possible to have an indoor above ground oil tank and an outdoor underground tank installed at the same property?

Photograph of a residential outdoor above ground oil tank - was this tank intended for outdoor use? Photo courtesy Arlene Puentes, Kingston NYIs it possible to have an indoor above ground oil tank and a outdoor underground oil tank located on the same home property?

Reply: Yes.


Your question, an excellent one, makes the point that just because you find an oil storage tank at a property, don't assume it is the only one present or only one that has ever been present. The older the property the more likely that there may have been more than one oil tank installed.

While there are no hard and fast rules or laws here are some examples and clues of cases that may arise - stuff to watch out for:

If you see a new-looking outdoor oil storage tank like the one shown here (above-left) installed on an OLD pad, an old above ground tank may have been replaced in the same spot.

If you see a new-looking outdoor oil storage tank and old oil piping remnants in the building then look for evidence or history of an old tank.

Local residential codes may limit the total volume of heating oil stored at a property (typically to 1100 gallons), but that does not limit the number of in use and old tanks that may be present.

There may be an indoor as well as an outdoor or even a buried outdoor oil storage tank all located at the same property. The history that we have run across typically involves a buried or underground oil storage tank that was abandoned and not properly removed following discovery of leakage; the property owner, needing to keep heat working, installs an above-ground oil storage tank indoors, or if there is no space indoors, s/he might install an outdoor tank.

We have also come across properties at which an indoor tank was old and leaky but the owner found it difficult to remove and with no space for another indoor tank the owner opted for an outdoor oil storage tank.

Watch out: if there is evidence or a report that a buried oil tank was abandoned in place OR was removed completely, be sure you obtain documentation that provides reliable evidence that the work was done properly and that any contaminated soils or leaks were cleaned-up.

Failure to follow-up on this oil tank question can leave a new property owner with an old, expensive surprise.



Continue reading at ABOVE GROUND OIL STORAGE TANK (AST) INSPECTION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see these

Oil Tank Inspection Articles

Suggested citation for this web page

OIL TANK INSPECTION & TROUBLESHOOTING at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Questions & answers or comments about heating oil storage tank inspection, diagnosis, & repair: location, leaks, piping, regulations

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

HTML Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman