How long does an ADU or DADU permit take in Seattle?
New-construction permits whose dwelling-unit type includes an attached or detached accessory dwelling unit (AADU or DADU), with or without a new house.
Window: permits issued Jul 1, 2024 to Jun 30, 2025. That is the latest year in which Seattle's open data still records the dwelling-unit type; newer permits no longer carry it, so we can't tell which ones are ADUs.
How this compares with the city's goals
SDCI's goal for pre-approved DADU plans is 30 days in City control; its reported 75th percentile is 60 days (SDCI permit performance, checked Oct 21, 2026). SDCI counts only days the application is with the City and notes the total wait an applicant experiences is roughly twice that. Our figure is the total calendar wait from application to issue, so it is longer.
All new housing permits in Seattle over the latest year: median 181 days (Seattle overview).
By ZIP code
| ZIP | Median days | Middle half | Slowest tenth | Permits |
|---|---|---|---|---|
| 98199 | 148 | 126–187 | 212 | 27 |
| 98103 | 166 | 113–217 | 242 | 39 |
| 98115 | 170 | 124–244 | 466 | 43 |
| 98117 | 185 | 138–283 | 522 | 57 |
| 98125 | 189 | 136–239 | 403 | 56 |
| 98133 | 190 | 128–238 | 375 | 34 |
| 98122 | 277 | 228–313 | 568 | 25 |
| 98118 | 330 | 170–756 | 963 | 54 |
ZIP codes with at least 25 permits in the window, fastest first.