Accessory Structures in Spokane, WA (2026)
9 verified accessory structures rules for Spokane, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Under Washington HB 1110 (middle housing) and HB 1337 (ADU), Spokane must allow at least two ADUs per single-family lot. No owner-occupancy requirement, no ADU parking requirement within half-mile of transit. ADUs up to 1,000 sq ft permitted.
Accessory Structures: Adu Rules
Few RestrictionsADU Permits
Spokane processes ADU permits ministerially under Spokane Municipal Code Chapter 17C.300, updated in 2024-2025 to comply with Washington HB 1337 (RCW 36.70A.680 et seq.). Two ADUs are allowed per lot in RA, R1, R2, RMF, and RHD zones. Applications go through the Permit Center at City Hall.
Spokane ADU Permit Process (SMC 17C.300)
Few RestrictionsADU Impact Fees
Under Washington HB 1337 (RCW 36.70A.681), Spokane cannot charge impact fees on ADUs under 1,000 sq ft and is capped at 50% of single-family rates for larger ADUs. Spokane has not adopted general school or park impact fees - only its Transportation Impact Fee under SMC 17D.075 applies, and even that is reduced or waived for ADUs.
Spokane ADU Impact Fees and HB 1337 Caps
Few RestrictionsADU Owner Occupancy
Under Washington HB 1337 (RCW 36.70A.696) and SMC 17C.300.110, Spokane does NOT require owner-occupancy for standard ADUs. A narrow exception applies when both an ADU and a short-term rental exist on the same lot - in that case one unit must be owner-occupied six months per year, effective July 11, 2025.
Spokane ADU Owner-Occupancy (HB 1337 Preemption)
Few RestrictionsADU Rental Restrictions
Spokane allows long-term rental (30+ days) of any ADU without restriction. Short-term rental of an ADU is allowed under SMC 17C.316.040 but only if the operator obtains an STR permit and city business license. Combined ADU+STR use on the same lot triggers a 6-month owner-occupancy rule under SMC 17C.300.110 (effective July 11, 2025).
Spokane ADU Rental Restrictions and STR Coordination
Some RestrictionsShed Rules
Sheds under 200 sq ft in Spokane are exempt from building permits per WA State Building Code and IRC R105.2. Setbacks still apply: typically 5 feet from side and rear property lines in residential zones.
Accessory Structures: Shed Rules
Few RestrictionsGarage Conversions
Garage conversions to living space are allowed in Spokane under HB 1337 ADU rules. Require building permits for framing, electrical, plumbing, insulation, egress windows, and WA State Energy Code compliance.
Accessory Structures: Garage Conversions
Some RestrictionsCarport Rules
Carports in Spokane require building permits and must meet setbacks, height, and lot coverage limits under SMC Title 17C. Front-yard carports generally prohibited in residential zones. Structural attachment rules apply.
Accessory Structures: Carport Rules
Some RestrictionsTiny Homes
Tiny homes on foundations can qualify as ADUs under HB 1337 in Spokane. Tiny homes on wheels (THOW) are regulated as RVs and generally cannot be permanent dwellings outside designated parks. Minimum 70 sq ft per WA code.
Accessory Structures: Tiny Homes
Some RestrictionsLooking for Spokane County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Spokane city rules.
Accessory Structures in Spokane County →