Setback requirements in Seattle, WA
Accessory structures in Seattle have their own setbacks, usually smaller than the house's. They change by zoning district, so look up your lot to see which table applies.
Rules last checked by a person on October 19, 2026. Guidance only; confirm with Seattle before you build.
Find your district
Neighborhood Residential (NR1, NR2, NR3)
| Shed: Front setback | Usually can't sit within 10 to 15 ft of the front lineConfidence: medium |
|---|---|
| Shed: Side setback | 5 ft from side linesConfidence: medium |
| Shed: Rear yard | Sheds may sit in the rear yard (the back 10 to 15 ft)A setback agreement with your neighbor may be required.Confidence: medium |
| Deck: Front (decks over 18 in) | Not within 10 to 15 ft of the front line |
| Deck: Side (decks over 18 in) | Not within 3 to 5 ft of either side line |
Citywide placement rules
| Fence: Side and rear (NR and multifamily zones) | 6 ft, plus 2 ft of arbor or trellis |
|---|---|
| Fence: Front or street-side setback | 4 ft max |
Sources
- Seattle SDCI, Sheds. Checked 2026-10-19.
You don't need a permit to build a shed if... the total area (or footprint) of the shed's roof is 120 square feet or less... single-story... sits on a simple concrete slab, pier blocks, or soil... not attached... not in or near an environmentally critical a…
- 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19.
Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
- 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19.
Require permits for all proposed construction or other development in the community...
- 2024 IRC R105.2, Work exempt from permit (text published by the City of Benson, AZ). Checked 2026-10-19.
One-story detached accessory structures, provided that the floor area does not exceed 200 square feet. Fences not over 7 feet high. Decks not exceeding 200 square feet in area, that are not more than 30 inches above grade at any point, are not attached to a…
- Seattle SDCI, Decks. Checked 2026-10-19.
You need a permit to build a deck if it is: More than 18 inches above the ground; A roof deck; In an environmentally critical area.
- Seattle SDCI, Accessory Dwelling Unit. Checked 2026-10-19.
Building a detached unit. You need a construction addition / alteration permit... only two of them may be ADUs. Certain standards do not apply to accessory dwelling units such as parking.
- Seattle Building Connections, ADUs and middle housing (July 2025). Checked 2026-10-20.
Size limits for ADUs have been raised to 1000 square feet across all zones... Setback and height standards have been loosened.
- Seattle SDCI, Fences. Checked 2026-10-19.
You don't need a permit if you're building a fence with a total height of 8 feet high or less that doesn't have masonry or concrete elements over 6 feet... In neighborhood residential and multifamily zones, our zoning code limits your fence height to 6 feet…