Island County, WA Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Island County, WA, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Accessory building includes
- sheds, shops, garages, barns (§17.03.040)
- Side/rear setback, existing lot
- 5 ft, R/RA/RF/RR Zones
- Side/rear setback, new lot
- 50 ft, R/RA/RF Zones
- Front setback, local road
- 20 ft, all rural zones
- Front setback, new lot on highway
- 100 ft
- Flood zone A size cap
- 625 sq ft accessory structure
Summary
In unincorporated Island County's Rural (R) Zone, a shed or other accessory building follows the same setback table as the house it serves. Island County Code section 17.03.060.C makes accessory buildings subject to the yard and road-classification setbacks in the county's general dimensional standards at section 17.03.180.S.
C.Setbacks. Unless otherwise provided in this chapter, setback requirements shall be as follows:1.Setbacks for single family detached dwelling units, mobile/manufactured homes and accessory buildings are specified in section 17.03.180.S.
Full Breakdown
Island County's zoning code defines "accessory use or building" as a use, structure, or building customarily incidental to a permitted or approved conditional use, and specifically lists sheds, shops, garages, greenhouses, barns, and detached ADUs as examples (Island County Code section 17.03.040). In the Rural (R) Zone, section 17.03.060.C states that setbacks for single-family dwellings, mobile and manufactured homes, and accessory buildings alike are specified in section 17.03.180.S, meaning a shed does not get its own, smaller setback: it must meet the same yard standard as the house.
That cross-referenced table sets the side and rear yard at five feet for existing lots in the Rural Residential (RR) Zone and for existing lots in the R, RA, and RF Zones, rising to fifty feet for new lots or parcels carved out of the R, RA, or RF Zones (section 17.03.180.S.3.d-e). Front, street-side, and street-rear setbacks instead key off the classification of the abutting road, running from 20 feet for a local access road up to 100 feet along an arterial, collector, or state highway on a new lot. The Planning Director may administratively shave up to thirty percent off a yard setback under section 17.03.210.D, and fences, retaining walls, and similar structures, unlike buildings, may be built right on the property line under section 17.03.180.S.7.e.
Sheds within a mapped special flood hazard area face an additional cap: an accessory structure used only for parking or storage cannot exceed 625 square feet of floor area in an A flood zone, or 100 square feet in a V zone, under section 14.02A.050.E.
Violations & Fines
Building an accessory structure that ignores the required yard setback, or that exceeds the flood-hazard floor-area caps in a mapped special flood hazard area, is a zoning code violation subject to the county's standard citizen complaint and code enforcement process under sections 17.03.250 through .260. A shed that does not meet the cross-referenced section 17.03.180.S setback can be required to relocate or be removed as a condition of any later building or land use permit.
Frequently Asked Questions
Does a shed get a smaller setback than my house?
How far does a shed have to sit from my property line?
Can I build a shed right on my property line?
Is there a size limit on a shed in a flood zone?
Sources & Official References
Other rules in Island County
How Island County compares: Shed Permit Requirements by City·Compare Island County to another location·View the Washington accessory structures overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.