Seattle issues a certificate of occupancy (C of O) for most new buildings, but SDCI Tip 120 says one is not required for single-family homes and duplexes (the R-3 occupancy) or for remodels that keep the same occupancy. For a house, the record to look for is the building permit’s completed final inspection. For an apartment, mixed-use or commercial building, it is the C of O itself.
Most new-housing permits in Seattle do reach that point, but slowly. In SDCI’s Building Permits data, 81.1% of the 4,205 permits issued from 2021 to 2023 that added housing units read Completed by October 2026, 13.1% read Expired and 5.8% were still Issued. The median permit took 463 days from issue to its last completed inspection.
How to find a Seattle certificate of occupancy or final inspection
- Search the address in the Seattle Services Portal, which holds SDCI permit, inspection and document records from 2005 on.
- Open the building permit and read its status. SDCI’s data defines the completed date as the date the permit had all its inspections completed.
- For an apartment, mixed-use or commercial building, look for the C of O in the permit’s documents. Tip 120 says it lists the building permit number, address, a description of the space, a statement that the space complies, and the building official’s name.
- If the certificate is missing from the portal, call SDCI Inspection Services at (206) 684-8950.
- For older buildings, research the SDCI Microfilm Library on the 20th floor of Seattle Municipal Tower, (206) 233-5180. Seattle first required C of Os in 1956, so an older building that never changed occupancy will have none on file.
Which Seattle buildings need a C of O, and how a temporary one works
- New buildings: most need a C of O before anyone uses or occupies them. A mixed-use building gets one certificate listing all its occupancies; theaters, restaurants and other assembly spaces need their own.
- Houses and duplexes: R-3 occupancies are exempt, so the permit’s final inspection is the record.
- Remodels and tenant improvements: a C of O is needed only when the building code occupancy changes.
- Existing buildings: an owner who wants a C of O for financing or a sale can apply for one without any construction, per Tip 120.
A temporary certificate of occupancy (TCO) lets people occupy part of a building before all of it is finished, once the fire and life-safety systems for that part are complete and inspected. It has an expiration date and stays tied to an active building permit, so the permit has to be renewed until the final C of O is issued. Tip 120 says occupying a building without a C of O carries financial penalties, and letting a TCO lapse without renewal can bring a Notice of Violation. The detailed TCO rules are in SDCI and Seattle Fire Department Director’s Rule 19-2017.
What 4,205 Seattle new-housing permits from 2021–2023 show
We took every SDCI building permit issued from January 2021 through December 2023 that added at least one housing unit, left out withdrawn permits, and grouped them by the dwelling type SDCI recorded. Completed counts the few permits in similar closed statuses, such as Inspections Completed, and days run from the issue date to the completed date.
| Housing type | Permits | Completed by Oct. 2026 | Expired | Median days, issue to completed |
|---|---|---|---|---|
| New house, with or without ADU | 1,435 | 86.9% | 9.2% | 467 |
| Detached ADU only | 1,069 | 87.7% | 7.5% | 409 |
| Attached ADU only | 368 | 84.5% | 9.0% | 378 |
| Townhouse or rowhouse | 703 | 85.3% | 8.4% | 507 |
| Apartment or small efficiency dwelling | 193 | 81.3% | 3.6% | 815 |
| All new-housing permits | 4,205 | 81.1% | 13.1% | 463 |
Apartment permits take longest and expire least. Their median was 815 days, and 14.5% were still Issued in October 2026; those 193 permits added 14,394 units. For houses, ADUs and townhouses the median ran from about 12 to 17 months, and one in ten of all new-housing permits took 1,002 days or more.
The All row also holds 437 permits with no dwelling type recorded, half of them additions and alterations to existing houses. 55% of them read Expired, the highest share of any group.
Pre-approved detached ADU plans finished on a similar schedule once issued: 179 permits, 87.7% completed, a median of 393 days, against 412 days for 905 custom detached ADUs. Any difference in review time before issue falls outside this count. Permits issued in 2023 show more still in progress, with 7.8% Issued and 78.7% Completed.
What an Expired permit means on a Seattle new house or ADU
An Expired building permit on a new house or ADU means the permit ran out before all of its inspections were completed. Ask whether a new permit was issued to finish the work and whether that one reads Completed. Our breakdown of expired building permits by project type shows how often Seattle remodel permits end the same way, and the permit status decoder reads a list of statuses for you.
What Seattle’s certificate of occupancy list shows for 2021–2025
SDCI publishes a separate Building Certificates of Occupancy list with the permit number, address, final C of O date, any temporary C of O dates and the occupancy type. It holds 5,227 records with C of O dates from 2005 onward. Search it by the building permit number (ending in -CN or -PH) when you need the date a building got its final certificate.
- Who gets one. Of 1,021 final certificates dated 2021–2025, 418 (40.9%) include an R-2 apartment or condominium occupancy and 106 list an R-3 occupancy, such as townhouses. The rest are offices, retail, assembly space, schools and garages.
- Temporary first. 386 of the 1,021 (37.8%) had a temporary C of O before the final one, and 239 of the 418 apartment and condo certificates (57.2%) did. The final C of O came a median of 83 days after the temporary one; 75% within 166 days and 90% within 362 days.
- How long a TCO runs. Across the list, temporary certificates had a median term of 90 days from issue to expiration (10% were 30 days or shorter, 10% longer than 249 days).
- TCOs that never closed. 124 records show a temporary C of O and no final date. 102 of them are past the TCO expiration date, and half of the 124 were issued more than six years ago. If a condo or apartment building you are buying shows only a TCO in this list, ask the seller or HOA for the final C of O or the current TCO, and check the building permit status.
These figures are our calculations from the SDCI certificate list on data.seattle.gov, downloaded October 25, 2026.
Checklist for a Seattle new home, ADU or condo
- House, duplex or ADU: the building permit reads Completed, with a completed date.
- Apartment, condo or mixed-use building: a final C of O, or a TCO with its expiration date and an active building permit behind it.
- Any Expired permit on the new construction, and the permit that replaced it.
- A building older than 1956 with no change of occupancy: no C of O is expected; the permit history in the Microfilm Library is the record.
- Open complaints at the address; see what happened to Seattle unpermitted construction complaints.
For the full Seattle search, see our Seattle building permit search guide. Our certificate of occupancy lookup guide compares CO records in other places.
Counts are our calculations from SDCI’s Building Permits data on data.seattle.gov, pulled October 24, 2026; statuses are as published that day. SDCI Tip 120 (updated October 16, 2023) checked October 24, 2026.