The rules are from the Seattle Fire Department's Client Assistance Memo 5962 (updated March 2024) and its permit code 6103 application (form dated 04/26), both read 23 October 2026.
The rule in one table
| Question | Seattle Fire Department answer |
|---|---|
| Which tanks | Residential heating oil tanks out of service for a year or more, with connected piping (Fire Code 5704.2.13) |
| Permit | Code 6103, one per tank, before work: "no permit will be issued after completion" |
| Fee | $184 per tank, for 1 to 4 residential units and tanks under 1,100 gallons |
| Who does the work | A current ICC Underground Storage Tank certificate holder, on site for the whole job |
| Options | Removal, or abandonment in place: triple rinse and wash, then fill with sand, concrete slurry or foam |
| Leaking tank | Remove rather than abandon |
| Soil samples, site plan | Not required under the Fire Code |
| Report | Decommissioning Report Form to SFD and the owner within 30 days |
The memo covers underground tanks; it does not address above-ground ones.
How the job runs
- The decommissioning company prepares the 6103 application; you sign it as owner. It names the tank company and the ICC-certified decommissioner, and the dates of the pump-and-rinse and the fill or removal.
- Send it to permits@seattle.gov and pay by card online, or mail it with a check payable to "City of Seattle" to the Fire Prevention Division, 220 Third Avenue South, 2nd Floor.
- Wait for the stamp "Approved to Proceed". No work before that.
- If the work date moves, the Fire Marshal's Office must be told in writing or in person "by 9:00 am of the day that the work will actually be performed." Missing either condition "renders the permit invalid and may result in criminal liability."
- Within 30 days, the decommissioner sends the report form to the Fire Department and gives you a copy.
What it means for hiring
Ask the tank company for the decommissioner's ICC certificate number and whether it is on file with the Fire Marshal's Office; ask whether the price is for fill-in-place or removal, and what happens if the tank turns out to have leaked, since the memo notes that Department of Ecology reporting may apply. Keep the stamped permit and the report form: the memo tells owners to keep them with all receipts.
If the tank is going because you are switching to a heat pump, ask whether the heat pump installer handles the tank or you hire a separate decommissioning company. Seattle's Clean Heat rebate for oil-to-heat-pump conversions is covered in heat pump vs. furnace in Seattle.
| Seattle heat pump permits, October 2023 to September 2026 | Value |
|---|---|
| Permits / firms | 15,441 / 272 |
| Usual filed value | $8,000 |
| Middle half of firms' usual job | $6,000 to $15,000 |
| Finished (permits a year or more old) | 85.6% |
| Usual days from issue to final | 105 |
| Firms matched to an active L&I registration | 76.1% |
| Firms whose registration is expired, suspended or similar | 36 (13.2%) |
| Busiest firm, last 12 months of the file | Greenwood Htng & Home Services (646) |
| Busiest / quietest month | June / January |
Heat pump permits peak in June and are lowest in January. 36 heat pump firms in our file matched a registration that is no longer active, so check the installer on L&I as our Seattle contractor license lookup shows.
Compare Seattle heat pump installers →
Prices by firm: Seattle heat pump cost. The heat pump permit: Seattle heat pump permit. Counts by year: Seattle permit statistics.
What this does not tell you
Fire Department tank permits are not in our file, so we cannot count decommissionings or rank tank companies; the table is heat pump installers, the trade most often hired alongside them. Our data does not show which heat pumps replaced oil. The memo lists no inspection by the Fire Department; the report form is the record.
How we know this
The decommissioning rule, options, steps and documentation are quoted from Seattle Fire Department Client Assistance Memo 5962 (updated March 2024) and the fee, scope and conditions from its permit code 6103 application (form 04/26), both read 23 October 2026. Our figures are Seattle mechanical permits classified as heat pumps, October 2023 to September 2026; finished share uses permits a year or more old, and registration status is matched to Washington L&I records by name.
Numbers come from City of Seattle (SDCI) building, trade and electrical permits on single-family and duplex homes (the city's open-data exports), data through October 17, 2026. Nobody paid to be on this page and nobody can.
Questions
- Do I have to remove my old oil tank in Seattle?
You have to decommission it, not necessarily remove it. Under Section 5704.2.13 of the 2021 Seattle Fire Code, a residential heating oil tank out of service for a year or more must be decommissioned with its piping, either by removal or by abandonment in place (triple rinsed, then filled with an inert solid such as sand, concrete slurry or foam).
- How much is the oil tank decommissioning permit in Seattle?
$184 per tank (permit code 6103), for homes of 1 to 4 units with a tank under 1,100 gallons. The Fire Department says a separate permit is required for each tank, and no permit will be issued after the work is done.
- Who can decommission an oil tank in Seattle?
The work must be done or overseen by a holder of a current ICC Underground Storage Tank decommissioning certificate on file with the Fire Marshal's Office, who must be present for the whole job. A homeowner gets the permit only if they hold that certificate themselves.
- Should I remove or fill my oil tank in place in Seattle?
The Fire Department advises removing a tank suspected of leaking rather than abandoning it, and warns that a tank abandoned in place may later have to be removed at extra cost. A site plan and soil samples are not required under the Fire Code, but Department of Ecology spill and leak rules may still apply.
- What paperwork should I keep after an oil tank decommissioning in Seattle?
The permit stamped 'Approved to Proceed', the Heating Oil Tank Decommissioning Report Form, which the decommissioner must give you and the Fire Department within 30 days of completion, and every receipt and certificate.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Do I need a permit for a heat pump in Seattle? Yes: a refrigeration permit only a licensed contractor can pull, and a 45 dB noise limit
- Washington's 2024 building and energy codes take effect 3 May 2027: what changes for new homes, additions and AC replacements
- Burlington, VT building permit search: how to look up permits on an address
- Heat pump vs furnace: what Seattle homeowners filed
For one city
- Client Assistance Memo 5962: Decommissioning Heating Oil Tanks — Seattle Fire Department (updated March 2024) (accessed 2026-10-23)
- Permit Application, Code 6103: Residential Heating Oil Tank Decommissioning — Seattle Fire Department (form 04/26, accessed 2026-10-23)