Oil Tank Decommissioning


*Note: Oil tank decommissioning is NOT a service that HAUS Inspection Services provides. Please see the service providers listed below. 

Buried TankOil tanks don’t last forever. Decommissioning is the official process of ensuring that the existing tank is either removed or made inert. In most cases this requires a qualified professional to locate the tank, remove any oil, and fill the empty tank with slurry or foam. Once decommissioned, a decommissioning certificate is provided. Official decommissioning of oil tanks has been required since 1996. If no record of decommissioning is available, it is possible that it was done before then or that the previous tank was installed above ground and did not require decommissioning. For Seattle area homes, see the resources below to check if a record of decommissioning is available. Local oil providers like “Filco” or “Tanks by Dallas,” may also have their own records of decommissioning (see “Service Providers” below). A record of decommissioning certificates since 1996 is also kept by the fire marshal (see address search tool link below).



Most homes that I encounter that currently use, or had previously used, oil as a heat source, do not require decommissioning. However, in if an oil tank is buried on the property and has leaked, or begins to leak, environmental remediation is often required. Remediation requires permits and often excavation of the old tank, which can be expensive. A leaking tank can often be caught (as water in the fuel system) during regular servicing of the furnace. In less common scenarios whereby an abandoned non-decommissioned tank is present, it is recommended that the tank be decommissioned quickly to prevent further environmental and cost concerns. Keep in mind that evidence of a previous tank is common and often identified during the inspection. In most of these cases the tank has been previously decommissioned and no further related concerns exist.

Even if a home is supplied with an energy source other than oil, it may be helpful to know if heating oil was ever used. Your inspector can often find clues of a previously used tank such as remnant oil lines, breathers, or labeling.

In the past the past, the insurance company known as PLIA (Pollution Liability Insurance Agency) used to offer oil tank leak and remediation coverage to Washington homeowners at no additional cost. This used to apply to new homeowner’s if the coverage was transferred into the new owner’s name shortly after closing. This coverage has changed significantly over the years check the PLIA website (link below) for further information.



Seattle Underground Storage Tank Records **(click “DATA” tab to search)**

Seattle area Fire Marshal’s office
(206) 386-1450



Seattle Fire Marshal (decommissioning records since 1997)
(206) 386-1450

PLIA (Pollution Liability Insurance Agency)
(800) 822-3905

Filco (decommission, locate, soil test)
Seattle: (206) 547-8347
Tacoma: (253) 922-6383
Everett  (425) 257-0509

Tanks By Dallas (oil provider, furnace service, decommissioning)
(206) 365-0291

Sound Oil (oil provider, furnace service)
(206) 725-6300


Please note that the information and resources provided here are intended only as a courtesy by Wil Harnecker and HAUS Inspection Services, LLC.. This information is not intended for use in making real-estate or other financial or health related decisions. Further research and due diligence is always recommended during all steps of the home buying and selling processes.