Washington Building Permits
Building permits in Washington are issued by cities and counties, not the state, so the rules depend on where your home is. These are the Washington city we cover: Seattle.
Washington Permit Activity at a Glance
Across the city below, we counted 13,214 issued permits for the home projects we track between October 30, 2025 and October 30, 2026. The counts come straight from each city's open permit data and are refreshed monthly. The busiest category was HVAC work in Seattle, with 12,661 permits. Where the data includes an application date, the fastest median time from application to issue was 0 days (HVAC in Seattle) and the slowest was 54 days (fence in Seattle).
Seattle Building Permits
4 project guides · 13,214 permits in 12 months · Seattle Department of Construction and Inspections (SDCI)
In Seattle, residential permits are issued by the Seattle Department of Construction and Inspections (SDCI). Our counts use the city's Seattle Building Permits dataset. Short answers for each project we cover:
- Roof replacement: Often no. For detached one- and two-family homes, re-roofing and replacing sheathing needs no permit when the building envelope does not change and the work is equal to or better than what exists. You need a construction permit if the re-roof alters the envelope beyond adding or replacing insulation.
- AC or furnace replacement: Yes. Furnaces and heat pumps need a mechanical (furnace) permit in Seattle, and split systems with refrigerant piping also need a refrigeration permit, which only a licensed contractor can get. New circuits or panel work add an electrical permit.
- New fence: Usually no. No permit is needed for a fence up to 8 feet total height without masonry or concrete elements over 6 feet, unless it is in a flood-prone area. Zoning can still limit height in required yards.
- New deck or porch: Sometimes. You need a construction permit for a deck more than 18 inches above the ground or any roof deck. Most decks on neighborhood residential lots get a same-day Subject-to-Field-Inspection (STFI) permit.
| Project Guide | Permit Needed? | Permits in 12 Months | Median Days to Issue |
|---|---|---|---|
| Seattle Roofing Permits | Often no | 455 | 40 |
| Seattle HVAC Permits | Yes | 12,661 | 0 |
| Seattle Fence Permits | Usually no | 10 | 54 |
| Seattle Deck Permits | Sometimes | 88 | 7 |
Not yet covered for Seattle: solar panel installation. We only publish a project guide when the city's open data identifies that work clearly enough to count at least 10 permits in 12 months and we have checked the rule against an official city source. Until then, ask the Seattle Department of Construction and Inspections (SDCI) directly before starting one of these projects.
How to Use These Washington Guides
Start with the city that issues permits for your address. If you live outside city limits, your county or township usually handles permits instead, and its rules can differ from the city pages here. Each project guide quotes the official rule, lists any fee the city publishes, and links to the source so you can confirm it before you start work. Permit counts show how often each kind of job is permitted locally, and median days to issue show how long a typical application took over the last 12 months. Rules and fees change, so treat the official source as final and call the permit office if your project is unusual.
Data last refreshed October 30, 2026.