How Much Does it Cost to Decommission an Oil Tank?

buried portland oil tank

If you’re planning to sell your Portland home, you’ll want to think about potential home hazards that might need to be addressed before putting it on the market. If you have an older home, chances are, it has (or had) a heating oil tank, whether it’s in use or not. To ultimately make the sale, you may need to get a certification letter from the Department of Environmental Quality (DEQ) and/or have a new site assessment done. This can apply even to those who have had their oil tanks previously decommissioned but not certified through Oregon DEQ.

Testing and then decommissioning is voluntary during your home ownership, but often becomes involuntary after a buyer’s home inspection. Discovered leaking oil tanks will set the Oregon DEQ into motion and suddenly the homeowner will become responsible for a certified decommissioning.

With a growing concern about oil tanks contaminating soil, even the ones that have been decommissioned in the past, buyers are often having this tested during their inspection periods. If soil contamination is discovered, it usually rests on the sellers to remedy the problem before the sale is finalized. Every soil contamination is reported to the Oregon DEQ by law.

History of Oil Heating Tanks in Portland

Portland’s homes with oil heating systems are declining (a few newer systems involve above-ground oil tanks), however, according to the DEQ, most homes in the area built before 1970 were built with underground storage tanks. Over time, tanks can leak, and even when emptied, they can create environmental hazards. Emptied tanks can cause soil and groundwater contamination, and non-decommissioned tanks can be a fire risk with residual chemicals vaporizing and moving into the air.

What Does it Mean to Decommission an Oil Tank?

A full decommission goes beyond simply emptying the heating oil tank and extends to cleaning it out and removing it completely or filling it with inert material, like slurry. A decommission can be completed by a homeowner (we don’t recommend you try this) or contractor, but it needs to be certified by a licensed service provider, after which a test for contamination must be done on the soil. When complete, documentation is then submitted to the DEQ, for a $100 filing fee (as of January 1, 2020), who will issue the confirmation letter.

Why is it Important to Decommission a Portland Heating Oil Tank?

In Oregon, sellers are required to disclose the presence of an oil tank—current or past—to potential buyers, even if it’s been decommissioned. 

Beyond the law, buyers have become more vigilant about oil tanks, likely due to the Environmental Protection Agency‘s (EPA) reclassification of carcinogenic chemicals present in heating oil, like naphthalene and ethylbenzene. The DEQ recommends soil re-testing for any properties with oil tanks that were decommissioned before 2009. Buyers may want to see a recertification before finalizing a home purchase, even though Oregon doesn’t require it by law.

What Does it Cost to Decommission a Heating Oil Tank in Portland?

Part of the cost included in an oil tank decommission is cleanup, which can vary, depending on how severe the contamination is. In most cases, a professional can perform a risk assessment in compliance with Oregon law without removing soil. A risk assessment and tank decommission is typically less than $3,000.

Sites with higher degrees of contamination may require soil removal and disposal. If groundwater has been contaminated, more testing and risk assessment needs to be done. Properties with high levels of contamination can range from $4,500 to $6,000, with some reaching over $10,000 for the most complicated cleanups.

To get a bit more specific, tank decommissioning can average around $1,257, ranging from $547 to $1,992.  An aboveground tank usually runs anywhere from $300 to $1,500, with an underground tank running between $1,000 to $3,500. Add in hazardous liquid storage, and that’s an extra $500 to $1,800, with soil testing and remediation running from $500 to $10,000.

Check your homeowner’s insurance policy or call your insurance agent before paying. Some will cover cleanup costs of this type (most will not). If you have an active oil furnace with an underground tank it is possible to purchase oil tank insurance in case it leaks in the future.

Where to Get Information about Decommissioned Tanks in Portland

If you’re the owner of a property with a decommissioned oil tank, double checking its history and gathering as much information as possible will help prepare you for potential buyers’ questions.

Learn Whether a Property Has an Oil Tank

For city of Portland homes only, you can find oil tank records on by following the steps below. (Keep in mind that finding no oil tank permit does not necessarily mean one doesn’t exist. Also, the images are old and blurry, so they may be difficult to read.)

  • Type in the property address in the upper right-hand corner search bar.
  • On the right-hand side of the screen, scroll down and click “Permits & Zoning,” followed by “Permits.”
  • Scroll down to the section called “Underground Storage Tanks.” (Note: If you don’t see this section, that means the property is in an area where permits are not available or there are no permits for the property.)
  • Click on the blue hyper-linked numbers in the “ID” column, and you’ll get an image of the permit, which you can download. The permit will show you where the oil tank is located on the property.

Learn Whether an Oil Tank Has Been Decommissioned (and there is a stored record of it with DEQ)

  • Visit the DEQ website.
  • Enter the property address and click “Lookup.”
  • Click on the blue hyper-linked number in the “Log Number” column. From here, you will learn: 1) if the tank has had any known leaks, 2) who was in charge of the clean up, 3) if it has been decommissioned. (You will see a “Closure Letter” at the bottom. If you don’t see one, this means the tank probably wasn’t decommissioned.) 

Do an Oil Tank Scan

You can also hire a professional to come to your property and do an oil tank scan to see if you have one on your property. If they find one, they will typically recommend testing the soil around it.

Have Questions About Decommissioned Oil Tanks on Your Property?

If you’re wondering about your potential liability, or if you simply want to know more about your home’s current market value, get in touch with our top 1% seller’s agents at 503-714-1111 or chat with the bot on our site. We’ve been successfully helping people sell homes in the Portland metro area for 19 years and would be happy to assist you in any way we can.

August 5, 2022

Stephen FitzMaurice

Stephen FitzMaurice, Realtor is a top 5% real estate agent in the U.S. A Principal Broker in Oregon, Managing Broker in Washington, he has been licensed since 2003 for residential real estate sales. Call his team in Oregon at 503-714-1111 or in Washington at 360-345-3833.

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