Oil Tank Maintenance

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Prevent Groundwater Contamination

oil tank

Oil spills can migrate very quickly into the groundwater. If you live in Riverdale, a spill in your yard could contaminate the drinking water aquifer very quickly.

The best way to prevent a leak or spill is to inspect and maintain your fuel tank. Read on for more information, or download a checklist here.

What to do if you have a leak or spill

Spills happen poster

If you see or smell fuel around your tank, you might have a leak or spill. Act quickly to prevent further spillage and groundwater contamination. 

  1. Stop the flow of oil at the source. If it’s a leak in the line, turn off the shut off valve at the tank. Plug the hole if it’s safe to do so, and place a container under the leak. Monitor how much is leaking.
  2. Absorb fuel using something absorbent (cat litter, absorbent pads, peat moss, rags, etc). Never flush any oil-soaked materials. Store them safely in a non-flammable container, outdoors, out of heat and dispose at Household Hazardous Waste Day.
  3. Prevent the fuel from entering floor drains or spreading to areas that are difficult to clean (such as under equipment, in corners, etc).
  4. Turn off the furnace.
  5. Call the 24-hour Yukon Spill Report Line at 867-667-7244. Visit Environment Yukon for more information about spill reporting.
  6. Call your oil supplier or an environmental service to arrange to pump out the remaining oil.
  7. Call your insurer as soon as possible.
  8. Document the spill--take photos and write down details.
  9. Indoor tanks--if the leak or spill is indoors, also:
    1. Turn off the power to the furnace
    2. Prevent fuel from entering floor drains
    3. Eliminate anything that might ignite the fuel, like smoking or flames, and appliances (don’t use a shop vac to clean up the fuel!).
    4. Be aware of the build-up of fumes indoors.
    5. If the spill or leak cannot be stopped, catch the flowing liquid using a pan, pail, hubcap, shovel or whatever is available. Spreading absorbent material, such as kitty litter, sand, ground corncobs, straw, sawdust, wood chips, peat, synthetic absorbent pads, or dirt. An absorbent may stop the flow and soak up the petroleum on pavement. (Note that this will not make the petroleum nonflammable.)

Proper tank

A proper tank is the first precaution against spills and leaks. The standard for oil tanks has increased over the past few years. Many existing tanks do not meet these standards.

Some insurers will not insure homes with outdated tanks. If you have owned your home for a long time, your insurer might not have asked you about your tank for several years.

secondary containment
  • Double-walled tanks are best. Single wall tanks are at a high risk to fail. Consider replacing it with a double-walled tank, which has an extra wall at the bottom. They can contain a leak for longer, although a metal inner wall will still corrode without proper maintenance.
  • Plastic or fibreglass tanks are preferable to steel, though more expensive. If you are replacing your tank in order to sell the house, a more expensive tank will be a selling feature to a new owner, who would likely have to replace a steel tank within a few years.
  • Secondary containment units are also available and should be able to hold 110% of the contents of the tank.


Fuel tanks should be inspected annually, along with your entire heating system. Follow the list below, or print off this checklist. If you observe any of the following, contact a certified oil burner mechanic for further advice.

  • Look for signs of oil--drips or ground staining. This might be a leak. Contact a certified oil burner mechanic or environmental company immediately and refer to the section above "What to do if you have a spill or leak."
  • Is there the smell of fuel? Try to check after each fill, which is when spills often happen.
  • Check for bent or pinched fuel lines
  • Check fittings for cross-threading
  • Is the fuel gauge cracked?
  • Keep your tank full (~80%), even in summer, to minimize condensation inside the tank, which can lead to corrosion. 
  • But don’t overfill. The fuel needs a head-space for expansion. With temperature increase, the fuel might back up through the fill pipe and cause a spill.
  • A vent whistle installed on the vent pipe should prevent the fuel delivery person from overfilling. Check to make sure your tank has one.
  • Add a fuel treatment periodically to disperse any moisture that can build up in the bottom of the tank.
  • Check for corrosion at the bottom of the tank. Corrosion happens from the inside out, so you might not see anything. If there is a dark line, there is likely corrosion. Don’t touch corrosion: you might make a hole.
  • Check for water in your tank. You can check this by putting line of water detecting paste on a long stick, then dipping the stick into your fill spout. The paste will change colour where there is water.
  • Ensure there's a rain cap on the tank's filler pipe and vent pipe to keep water out.
  • Look for nearby hazards: can the tank be affected by moving cars, equipment, falling trees, children playing, passersby?
  • Keep fuel lines clear of snow and falling branches.

Removing water from your tank

If you have water in your tank, you can use a home heating fuel additive to displace water and eliminate sludge. Some companies add this routinely, while others do it on request.

For small amounts of water, you can also it using a number of water absorber products. They are typically a pouch of absorbant that is lowered into the tank and removed after about a day. Brands include H2O Water Worm, Water Snake, and Water Magnet.

Replacing your tank

It's likely that at some point your tank will need to be replaced. If you make the decision to replace your tank,there are a few things to keep in mind.

  • You cannot install a second-hand tank.
  • Oil should not be transferred to a new tank unless it is filtered. Sludge, acid , water and microorganisms will contaminate the new tank.
  • A tank must be placed on a single solid pad, on undisturbed, or compacted soil, and the tank needs to be bolted to the slab to prevent toppling, lifting, settling, due to earthquakes, floods, are ground settlement.
  • Only a certified oil burner mechanic can install an oil tank.
  • Your insurance company might have a different standard, so contact them beforehand.

Proper tank location

When installing a new oil tank, a certified oil burner mechanic must meet certain requirements, which are outlined in this checklist.

Your oil tank might not meet the current standards. Look at your outdoor tank and see whether it is located correctly.

  • Tanks should have space around to allow air movement and inspection. They shouldn’t be under decks or stairs.
  • Tanks should not block doorways or windows.
  • Tank’s vent pipe must be at least two feet from opening windows, and away from ventilation air intakes.
  • Tanks should be in a safe, out-of-way location and protected from vehicles, wind, falling branches, ice or snow. Children should not play on or near fuel tanks or lines.
  • Avoid south-facing installations. Tanks that get a lot of sunlight will degrade more quickly.

If your tank is not well located, consider having it moved by a professional. It must be empty first. Contact your fuel company or an environmental service to pump it out.

If moving your tank is not practical, consider installing a solid barrier to protect it from vehicles, and make sure fuel lines are protected.

For indoor tanks, you can read more about proper location in “A Guide to Home Heating Oil Tanks”.

Fuel line protection

New tanks are installed to minimize fuel lines and keep them protected. Your tank might not have been properly installed, or lines might have shifted. Consider the following when inspecting your tank.

  • There should be easy access to the line for inspection.
  • All line connections must be tight. If a connection is dirty or dark, it could be leaky.
  • Oil filters should be located indoors near your furnace, not outside. They should be changed every year by a certified burner mechanic.
  • Buried single-wall fuel lines are no longer allowed because they can rupture and leak undetected.
  • Fuel lines must have a water proof jacket where they pass through walls and have secondary containment (double walled) if they go underground.
  • Fuel lines should be protected from falling ice, especially near roofs. Shield the lines, or have them moved
  • Keep lines clear of drifting snow.
  • Do not let children or animals play on or near fuel lines

Tank support and restraints

There are standards for how a tank is secured. Your tank might not meet these standards. Verify that your tank is stable and resistant to shifting or earthquakes.

  • The ideal foundation for a tank is a large reinforced concrete pad with the metal tank or tank stand is bolted down. Patio stones or sidewalk blocks are not stable enough.
  • tank stabilityThe ground underneath the concrete pad must be non-organic, undisturbed, and well compacted, to prevent shifting over time. Water should be able to drain through, to prevent shifting from the ground freezing and thawing.
  • Wooden tank stands are prohibited and must be replaced.
  • Tanks should never be fastened to the wall of a building.
  • Tanks must have adequate seismic restraints.

If your tank is not stable, consider hiring a certified burner mechanic or environmental company to add stability. Your tank might be deficient in several aspects, which would warrant replacement rather than relocation.