Permit Required? Sometimes Required
Typical Fee Range $292–$600 Exempt if 120 sq ft or less and detached; $292 minimum base fee per hour for permitted work (2026).
Fee Method Valuation-based
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What's Required in Seattle

  • No permit required for detached storage sheds up to 120 square feet.
  • Shed must not be used for living, home office, or any habitable purpose.
  • Must maintain 5-foot setbacks from property lines if over 120 sq ft.
  • Any shed with electrical wiring, plumbing, or mechanical work requires a permit regardless of size.
  • Maximum height for detached accessory structures is 12 feet (Standard) or 15 feet (Sloped).
  • Subject to 'Environmentally Critical Area' (ECA) restrictions if lot has slopes >40%.

What Size Shed Needs a Permit in Seattle

Whether you need a building permit for a shed in Seattle usually comes down to size. In Seattle, the cutoff is clear: detached sheds of 120 square feet or less don’t need a building permit, while anything larger does. A popular 10x12 shed (120 sq ft) lands exactly on the limit — at that size it’s still exempt, but going any bigger triggers a permit. Larger sheds, and any shed with electrical, plumbing, or a permanent foundation, almost always need a permit regardless of footprint.

Building a Shed Without a Permit in Seattle

Even when a shed is small enough to skip a building permit in Seattle, “no permit” doesn’t mean “no rules.” A permit-exempt shed generally must stay at or under the 120-square-foot limit, sit on a non-permanent base (sheds on skids or a gravel pad are treated more leniently than those on a poured foundation), and have no electrical or plumbing run to it. Crucially, zoning setbacks still apply — your shed usually has to sit a minimum distance from property lines and other structures, and that holds even for a permit-free shed. Confirm both the size exemption and the setback distance with the Seattle Department of Construction and Inspections before you build.

How to Get a Shed Permit in Seattle

1

Step 1: Size Verification

Measure the footprint to determine if the 120 sq ft exemption applies.

2

Step 2: ECA Check

Verify if your lot is in an Environmentally Critical Area which removes exemptions.

3

Step 3: Portal Submission

Submit a 'Building' permit request on the Seattle Services Portal if over threshold.

4

Step 4: Fee Payment

Pay the permit fees ($292/hr base rate for 2026).

5

Step 5: Inspection

Schedule a final structural inspection once the shed is anchored.

Frequently Asked Questions

Yes, 120 sq ft is the maximum exempt size; any shed larger than that needs a permit.
Typically 12 feet, but can go up to 15 feet if it has a sloped roof and meets setbacks.
No, Seattle zoning generally restricts accessory buildings to the rear yard.
In Seattle, sheds of 120 square feet or less can be built without a building permit; anything larger needs one. The exemption usually also requires no permanent foundation and no electrical or plumbing, and zoning setbacks from property lines still apply even without a permit.
Often not, if it’s also within Seattle’s 120 sq ft limit and has no utilities — many jurisdictions treat a shed on skids or a gravel pad as movable rather than a permanent building. A poured foundation or any electrical/plumbing typically triggers a permit. Confirm with the Seattle Department of Construction and Inspections; zoning setbacks apply either way.