heating oil spills

Spilled heating oil can be a big problem. Have you checked your tank?

On average, the Maine Department of Environmental Protection responds to 1.5 spills every day from home heating oil tanks alone. Will your tank be one of them?

There are approximately 400,000 home heating oil (HHO) tanks in Maine. Many of these tanks meet the DEP “high risk” criteria and are in need of replacement to prevent spills. Heating oil spills can cause long term pollution in your drinking water and the air in your home, decrease the value of your home, and cause ecological damage to the surrounding environment. These preventable spills have resulted in millions of dollars spent on associated clean-up costs and have disrupted thousands of lives and homes. Is your tank a “high risk” tank?

We all can play an important role in preventing heating oil tank leaks by periodically checking our tanks. Unfortunately, tanks do not last forever. One of the greatest pollution threats to our groundwater, wastewater and stormwater is unintentional leakage of home heating oil from older, corroded heating oil tanks through basement floor drains and sump pumps.

Inspect your heating oil tank and answer the following questions to find out if your tank is at risk of causing a spill. Look but do not touch, as a rusty or oily patch on the tank could indicate a leak or a weak spot.


#1 - Tank Corrosion due to water and sludge build-up. A licensed oil heat technician can conduct an ultrasonic thickness test to determine steel thickness, which can indicate whether significant corrosion has occurred. Ultrasonic thickness testing is best used for tanks under 20 years old. For tanks over 20 years old, it is time to start planning for a tank replacement.

#2 - Parts Failure can result from age, corrosion, and damage sustained from weather events. This includes but is not limited to rusted tank legs, unprotected filters damaged from falling ice or snow, and corroded fuel lines.

#3 - Human Error spill causes include tank overfilling, improper maintenance or repair efforts, and damage to fuel lines and parts due to human activity.



Please look - don't touch. A rusty or oily patch on the tank could indicate a leak or weak spot. The diagram shows where to check your tank on questions 1-9.

Heating oil leakage tank diagram

  1. Is the tank leaning, unstable, or on an unstable base? Outside vertical tanks must stand on a one piece, reinforced concrete pad. Outside horizontal tanks must stand on a one piece, reinforced concrete pad or solid concrete blocks.
  2. Is the piping buried underground, in concrete, or installed under a basement floor without continuous sleeving? Continuous sleeving leaves a gap between the line and the inside of the sleeve.
  3. Is the tank patched or showing signs of corrosion? Do you see rust, weeps, wet spots, or excessive dents on the tank surface?
  4. Is the tank a crimped end tank? Crimped end tanks are usually weaker than tanks with modern capped ends. Look for an obvious rim or edge (crimped), rather than a round/smooth end (capped).
  5. Does the oil exit through a fitting from the side or top of the tank rather than from the bottom? A bottom oil outlet minimizes trapped water and reduces rust inside your tank. NOTE: This does not apply to Roth double wall tanks or equal.
  6. Are there any visible drips or signs of leakage around the filter, valves, or other fittings?
  7. Could the tank’s vent be clogged or blocked? Check for ice, snow, or insect nests. A blocked vent can cause a silent overfill whistle when the tank is being filled. If you’re not sure, ask your oil delivery driver.
  8. Are there any signs of spills around the fill pipe?
  9. Is the tank's gauge cracked, stuck, or frozen? Do you see oil or staining around it?
  10. Is the tank made of steel and more than 25 years old?
  11. Can snow or ice fall on the tank, filter, or piping? A filter protector can help avoid this threat.
  12. Is the tank a 55-gallon drum or other container not listed for supplying oil to heating appliances?
  13. Is the tank no longer in use but still containing oil? Or is there a fill pipe in place for an old tank that is no longer there?
  14. Is your heating oil supply system not in compliance with the standards of the Maine Fuel Board? Consult a service technician as needed.

If you answered yes to one of the above questions, your tank may be in danger of leaking or causing a spill.

If you receive fuel assistance, you may be eligible for assistance with replacing your oil tank, contact Kennebec Valley Community Action Agency at (207) 859-1500 for more information.



Replacing your tank?

Consider investing in a smarter and safer design. Corrosion-resistant fiberglass, double-walled, or double-bottom tank designs help prevent spills and leaks, and can save you money in clean-up costs.

*The tanks shown below are examples of newer heating tank designs.

Heating oil tanks

Do you need help paying for a new tank or parts?
Homeowners who have questions about available programs to help pay for tank replacements but have limited income should contact Kennebec Valley Community Action Program at (207) 859-1500. Not all programs are income based, just the tank replacement program. If homeowners need to replace ancillary tank parts like filter protectors, gauges, fill and vent lines, or fuel lines, they should contact Maine DEP about the Home Heating Oil Ancillary Tank Equipment Replacement Program. You could be eligible for up to $500 towards the replacement of these items. Even if you don’t meet eligibility requirements, there may be assistance available. Contact MaineDEP at (207) 481-6860 for more information on these programs.

Who should you contact to report an issue?
If you have a spill or leak, call Maine Dept. of Environmental Protection’s 24-hour spill reporting hotline at (800) 482-0777. Help is available to all owners of above ground oil storage tanks with spills or leaks that affect the environment through the Ground and Surface Waters Clean-Up and Response Fund.