Seattle eliminated all owner-occupancy requirements for ADUs in 2019 under Ordinance 125854, and this is now reinforced by Washington HB 1337 (codified at RCW 36.70A.696) which prohibits cities from imposing owner-occupancy on ADUs statewide. SMC 23.42.054.B.4 explicitly states no owner-occupancy is required.
Seattle Ordinance 125854 (effective July 2019) removed owner-occupancy as a condition of ADU permitting and is codified at SMC 23.42.054.B.4. HB 1337, signed in May 2023 and codified at RCW 36.70A.696, prohibits all Washington cities from requiring owner-occupancy for any ADU permitted after July 23, 2023. There is no deed-restriction requirement. The owner can rent both the principal dwelling and the ADU(s) to separate tenants. Properties on the same lot are subject to Seattle's Rental Registration and Inspection Ordinance (RRIO, SMC 22.214) once any unit is rented. ADUs subject to the city's Mandatory Housing Affordability bonus or affordability covenants (rare for ADUs since MHA does not apply) retain those restrictions. Landlord-tenant rules under SMC 22.206 apply once an ADU is rented, including just-cause eviction.
There is no penalty for non-owner-occupancy of an ADU itself. Failure to register an ADU rental with RRIO under SMC 22.214 is subject to fines of $150 per unit per day. Violations of just-cause eviction rules (SMC 22.206.160) can result in tenant damages of 2-3x rent plus relocation assistance.
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See how Seattle's adu owner occupancy rules stack up against other locations.
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