Bellingham, WA Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- State law
- HB 1337 bars ADU occupancy mandates
- City ADU rule
- No owner-occupancy required (20.10.036)
- Fee exemption
- Owner-occupied attached ADU only
- Max ADUs per lot
- Two, attached and/or detached
Summary
Bellingham does not require owner-occupancy to build or rent an ADU -- state law (HB 1337) bars that -- but an owner-occupied attached ADU is exempt from the rental registration fee under BMC 6.15.040(B)(4).
Accessory dwelling units when an owner resides in either the single-family residence or the ADU and the ADU is attached to the single-family residence.
C. A residential rental registration expires on December 31st of the calendar year following registration or renewal.
D. The residential rental registration is transferable to any person who has acquired ownership of a registered rental property for the unexpired portion of the one-year term for which it was issued.
E. Application. Application for a residential rental registration shall be made to the city on a form and through a process established by the director. The application shall include the applicable registration fee, including late fees if applicable, the name, mailing address, email address, and telephone number of the owner or owners of the rental unit, a certificate of inspection unless the rental property is exempt under subsection (B) of this section, and such other information as required by the director in order to carry out the intent of this chapter.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 2026-06-015, passed June 1, 2026).
Full Breakdown
Washington's 2023 ADU law (HB 1337, RCW 36.70A.681-.685) bars cities from requiring owner-occupancy as a condition of building or renting an accessory dwelling unit, and Bellingham's ADU standards in BMC 20.10.036 impose no such requirement -- up to two ADUs are allowed per lot regardless of who lives on site. The one place owner-occupancy still matters is the rental registration fee: BMC 6.15.040(B)(4) waives the registration fee for 'accessory dwelling units when an owner resides in either the single-family residence or the ADU and the ADU is attached to the single-family residence.' Detached ADUs and non-owner-occupied properties still pay the fee and register normally.
Violations & Fines
There's no owner-occupancy violation for ADU permitting itself; failing to register the rental property at all, or to pay the fee when not exempt, triggers the penalties under BMC 6.15.150 -- $200-$500 per day.
Frequently Asked Questions
Does Bellingham require the owner to live on-site to build an ADU?
Is there any Bellingham benefit tied to owner-occupying an ADU?
Sources & Official References
Other rules in Bellingham
Compare Bellingham to another location·View the Washington accessory structures overview
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