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Frequently Asked Questions about Decommissioning, Cleanup Costs and Laws


​Underground heating oil tanks are a potential source of contamination of the soil and groundwater, may pose a fire and explosion hazard under certain conditions, and heating oil from leaking underground tanks may impact human health. Underground tanks also corrode and over time may weaken to the point where they can no longer hold fuel.

​​We recommend that you hire a DEQ-licensed service provider to perform this work for you. A list of contractors is available on this website or by calling toll-free at 1-800-742-7878.

If you are thinking about decommissioning your own tank, you can access the regulations on this website or you can call toll-free at 1-800-742-7878 and have a copy of the information mailed to you.

If you have any questions after you have read the rules and regulations, you can call 503-229-6170 and talk with a heating oil tank specialist.

​The empty, inert (rendered explosion-free), and cleaned tank can be recycled with any metal recycler or disposal facility. Disposal receipts should be saved.
​An oil dealer or an oil recycler can pump the oil out of the tank. Look in your phone directory under oil or waste oil for the names of companies who perform this service.
​Above-ground heating oil tanks are not regulated by the DEQ, so decommissioning and certification are not necessary.

​​​​No, the DEQ does not recommend contractors. We can provide you with a list of licensed contractors​ or let you know if the contractor you have selected is currently licensed.

You can also make an appointment to review the DEQ service provider file for a contractor you are interested in hiring by calling 503-229-6170. You may also want to call the Oregon Construction Contractors Board in Salem at 503-378-4621, x4900 to see if the contractor has had any complaints and that their Construction Contractors Board license is current.

This information is also on the Construction Contractors Board Web site.

Homeowners and Realtors

​It has come to DEQ's attention that contractors are being asked to recertify sites that have previously been issued a No Further Action letter by DEQ prior to 2/17/2000 or been certified as meeting standards by a contractor after 2/17/2000. The issue becomes what reliance, if any, can contractors and/or homeowners place on those earlier decommissioning or cleanup determinations. The advice DEQ has been giving is that the earlier determinations remain valid if:

  • No evidence exists to suggest a new release has occurred.
  • New site assessment data is consistent with the data submitted and relied on to make the earlier determination.
  • DEQ has not challenged the reliability of the earlier data through an enforcement action.

If the contractors or homeowners have any questions about the new information, they should contact the HOT technical staff for assistance or send an email.

On a related matter, DEQ is occasionally asked how long the results from a site assessment are valid where an active tank remains in the ground. Because new spills or releases from an active tank can occur at any time, DEQ advises that site assessment samples should be relied on for no more than 90 days. After 90 days it is advisable for new assessment data to be collected. DEQ will not accept site assessment data that is more than 90 days old if used to certify a decommissioning or cleanup.

​For the purposes of DEQ's program, a heating oil tank is an underground tank used for storing heating fuel for use on site. The heating oil tank is part of a heating oil system that should be maintained and, if necessary, replaced just as roofs, appliances, furnaces and water heaters that require on-going maintenance and are replaced when they are no longer useful. The useful life of an unprotected steel tank is about 20 years.

​Oregon law (ORS 466.878) requires the owner to pump out all heating oil from an abandoned (unused) underground heating oil tank when:

  • The tank is no longer used as a heating source.
  • The tank has been replaced with a new one.
  • The home or business is sold.

Please refer to: Requirements for Heating Oil Tanks No Longer in Use

Over the past several years, DEQ has made a concerted effort to make summary information from its files on tanks and hazardous substance-contaminated sites available over the Internet. That said, contractors and homeowners must realize that the data is incomplete in the sense that not every tank (i.e., residential heating oil tank, small tank or farm tank) and contaminated site (most reporting systems exclude certain small releases and often exclude residential releases) is regulated by DEQ. Notwithstanding these limitations, however, very useful information can be gleaned by initially searching the three on-line databases listed below.

DEQ offers three bits of advice in using the databases:

  1. When using the databases for the first time, please review the instructions for use that come with each database;
  2. Computers search for exact matches, therefore, put in only the information that you are positive about; and
  3. In conducting computer searches, less information to match is often better than too much information to match (while you may have to review 20 results from the search to find the one site you are looking for, it's more likely that the site will show up on the list of 20 sites).

The following databases are available via the "Data and Reports" link above:

Environmental Cleanup Site Databases
Searchable databases of Oregon sites with known or suspected hazardous substance contamination. Includes sites that have already been cleaned up.

Facility Profiler
A GIS mapping application showing which of DEQ's environmental programs (air quality, water quality or land quality) are active at given locations.

Leaking UST Cleanup Site Database
Searchable database of Oregon sites that have had a release of petroleum products from an underground storage tank, including a heating oil tank. Includes sites that have already been cleaned up.

To locate a buried tank first try to find the fill pipe (where fuel was delivered by the fuel truck) or the vent pipe. The fill pipe will often be close to the ground over the tank. The vent pipe is usually visible up the side of the house 2 feet to 8 feet above the ground surface. Each set of pipes leads to the top of the tank, which is typically 2 feet below the ground. Attempt to locate the furnace that was fueled by the heating oil tank, and track the piping out through the foundation to the tank.

You can also determine whether other homes in the area had heating oil tanks. If adjacent homes built during the same time have tanks, then it is likely that there may be a tank on your property.

​If the information provided does not answer your question(s), you may call, 503-229-6170 and ask to speak to a HOT project manager, or toll-free by calling, 1-800-742-7878, and ask to be transferred to the HOT program.
​The files will not be reopened because of a rule change. Typically, the only time a file is reopened is when new or undisclosed facts show that the cleanup does not comply with rules in place at the time of cleanup.

In the Oregon law directing DEQ to establish a contractor certification program for HOT decommissionings and cleanups, DEQ must establish provisions to reject certifications and require additional work to correct deficiencies when projects don't meet standards. When adopting the heating oil tank rules in February 2000, the Oregon Environmental Quality Commission established four criteria for rejecting certifications:

  • Lack of information or data to support a finding of compliance (such as inadequate sampling to define magnitude and extent of contamination or failing to analyze impacts to groundwater or indoor air, when those resources are affected).
  • Compliance determination is not correct, based on information provided.
  • Information provided does not accurately represent site conditions.
  • There is a violation of applicable rules.

Upon completing an audit and concluding that the project is not complete, DEQ sends out a letter to the contractor, with a copy to the homeowner, which identifies the additional work required to bring the site into compliance with the HOT rules. DEQ reminds contractors that OAR 340-163-0070(5) places the responsibility for any additional work resulting from the rejection of a certified report on the contractor or its errors and omissions insurer, not the property owner. However, completion of any additional work required by DEQ must be coordinated with the property owner.

Unless otherwise stated or agreed to in writing, DEQ expects that contractors will complete the additional work within 30 days and report their actions to DEQ. If contractors fail to complete the additional work in the time given, DEQ may take one or more of the following steps:

  • Deny renewal of a contractor's license, or suspend or revoke an existing license,
  • Advise the homeowner to file a claim with the Construction Contractor Board and/or against the errors and omissions insurance policy required by DEQ rules.
  • Take enforcement action, including imposing a civil penalty.

If contractors have any questions regarding the additional work required in a rejection letter, contractors should immediately contact the HOT staff person listed in the letter. HOT project managers are available to discuss non-compliance issues and proposed solutions to get sites certified, registered and files closed. Similarly, if the additional work cannot be completed within 30 days, the reasons for needing additional time should be sent to DEQ along with a proposed work schedule. DEQ expects contractors to react promptly to its rejection letters, otherwise appropriate enforcement actions will be taken.


The file will not be reopened because of a rule change. Typically, the only time file is reopened is when new or undisclosed facts show that the cleanup does not comply with the rules in place at the time of cleanup.
A soil matrix cleanup is one of several approaches for addressing heating oil contamination and involves the removal of most, if not all, of the contaminated soil at a cleanup site. For more information, refer to the Heating Oil Underground Storage Tank Rules, see Laws and Regulations link above.
​The heating oil tank generic remedy is one of several approaches for addressing heating oil contamination. The generic remedy involves property where some low-level contamination can remain at the site. This may involve some soil removal to achieve the requirements. This method cannot be used for sites with groundwater present in the area of the tank.

​A risk-based cleanup is a method for addressing heating oil contamination that may allow you to leave much of the contamination on the property. A more extensive investigation and evaluation must show that the contamination can remain without posing a risk to human health and the environment. A risk-based cleanup is typically used when removal of contamination may undermine the foundation of the house, or when costs to remove contamination are prohibitive.

Depending on the extent of contamination and other relevant factors, the responsible person should determine which cleanup option is best suited for the contamination release. Financial considerations, site-specific information, personal preferences of the property owner, and the ability to remove contamination help to determine the best approach.

HOT decommissioning and cleanup laws and regulations

Oregon Revised Statute

ORS Chapter 465 - Hazardous Waste and Hazardous Materials I
Sections 465.200 to 465.455 and 465.900

ORS Chapter 466 - Hazardous Waste and Hazardous Materials II
Sections 466.706 to 466.845, 466.994 and 466.995

Oregon Administrative Rules

Division 12 - Enforcement Procedures and Civil Penalties

Division 122 - Hazardous Substance Remedial Action Rules
Cleanup Rules for Leaking Petroleum UST Systems OAR 340-122-0205 to 340-122-0360

Division  163 - Registration and Licensing Requirements for HOT Soil Matrix Service Providers and Supervisors

Division 177 - Residential Heating Oil Underground Storage Tanks