Island County, WA Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- Attached ADU size cap
- 1,000 square feet
- Detached ADU size cap
- 1,200 square feet
- ADUs per lot
- one, attached or detached
- Owner occupancy
- required for attached ADU only
- Home business
- prohibited in attached ADU
- Applies in
- Freeland NMUGA zoning districts
Summary
In the Freeland zoning code, an attached accessory dwelling unit capped at 1,000 square feet must sit inside a primary home the owner actually occupies, and the ADU's residents cannot run a home occupation or home industry out of the unit.
6.Attached ADU. In order to encourage the provision of more housing options, attached ADUs may be established, subject to the following criteria.a.No home occupation or home industry shall be permitted for the residents of the attached ADU.b.An attached ADU shall be no greater than 1,000 square feet. ... d.An Attached ADU shall be located within an owner occupied primary residence.
Full Breakdown
320(A). Only one ADU, attached or detached, is allowed per single-family dwelling. 320(A)(6)(b). 320(A)(6)(d) then ties the unit to owner occupancy: an attached ADU shall be located within an owner occupied primary residence, meaning the property owner has to live in the main house, not the accessory unit, for the arrangement to qualify. 320(A)(6)(e) requires an addition that extends beyond the primary home's footprint to match its architectural style, materials and color. 320(A)(5): they max out at 1,200 square feet, cannot exceed the footprint of the main house, need a building permit application in the name of the lot's owner, and cannot be sold off or transferred as a separate parcel unless the resulting lot independently meets the county's minimum lot size and density standards. Both ADU types need one on-site parking space, though the Planning Director can approve on-street parking when site constraints leave no room for it.
Violations & Fines
Renting out or occupying an attached ADU while the owner lives elsewhere puts the unit out of compliance with section 17.06.320(A)(6)(d), which Island County Planning and Community Development can flag during a building permit review or a code enforcement complaint. Running a business out of an attached ADU, or building one larger than the 1,000-square-foot cap, is likewise a zoning violation subject to correction before further permits are issued.
Frequently Asked Questions
Does the owner have to live on-site to build an attached ADU in Freeland?
Does the owner-occupancy rule apply to detached ADUs too?
Can I run a business from my attached ADU?
Sources & Official References
Other rules in Island County
Compare Island County to another location·View the Washington accessory structures overview
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