Auburn, WA Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Auburn, WA, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Governing section
- ACC 18.32.010(E)(3)
- Exterior rule
- Garage door replaced to match house exterior
- Size floor/cap
- ADU 300-1,000 sq ft, garage space excluded
- Parking
- 1 space/ADU unless within 1/2 mile of transit
- Permit step
- Recorded county statement required before final
Summary
Auburn lets homeowners convert garage space into an accessory dwelling unit, but ACC 18.32.010(E)(3) requires the garage door be swapped out for materials matching the house's exterior, and the converted square footage cannot count toward the ADU's minimum size.
E. Exterior Appearance/Modifications.
1. Any alterations shall not change the appearance from that of a single-unit detached dwelling, as determined by the planning director.
2. Any exterior stairs shall be placed in the rear or side setback and no closer than 10 feet to an adjoining property line.
3. Where garage space is converted to living space, the garage door shall be replaced with materials that match the exterior of the house.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 7023, passed July 6, 2026).
Full Breakdown
010(A), and a garage can be converted into part of that living space. 010(E), which governs exterior appearance and modifications: any alteration cannot change the building's look from that of a single-unit detached dwelling, as determined by the planning director, and subsection (E)(3) specifically requires that where garage space is converted to living space, the garage door must be replaced with materials matching the house's exterior. 010(D) caps every ADU at no larger than 1,000 square feet and no smaller than 300 square feet, with no more than two bedrooms, and states plainly that garage space is excluded from that calculation.
010(E)(2). 010(F) requires one on-site parking space per ADU unless the property sits within a half-mile walk of a major transit stop, in which case no off-street parking is required. 010(K)(2) requires the owner to record a statement with the county confirming the ADU permit was submitted and that future owners must keep the unit in compliance with the Auburn Zoning Code. 010(K)(1). 010(L) requires permits and inspections from the city before the recorded statement can be released.
Violations & Fines
A garage conversion built without matching the garage door replacement to the home's exterior, or one that quietly counts garage floor area toward the ADU's minimum size, is out of compliance with ACC 18.32.010(E)(3) and (D) and can be denied final inspection by the city's building division. Occupying or renting the converted space before the city finals the permit and the recorded title statement is on file with the county risks a stop-work order and permit revocation, since the statement itself warns that future owners must comply with the Auburn Zoning Code for the unit to be lawfully occupied or rented.
Frequently Asked Questions
Can I convert my garage into an ADU in Auburn?
Does the converted garage square footage count toward the ADU size limit?
Do I need city approval before renting out a converted garage ADU?
Sources & Official References
Other rules in Auburn
Compare Auburn to another location·View the Washington accessory structures overview
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Garage Conversions in Nearby Cities
How other cities in King County handle garage conversions.