Vancouver, WA Accessory Structures: ADU Permits (2026)

VMC 20.810 governs ADU development standards in Vancouver. An ADU is defined at VMC 20.810.020 as one or more rooms with private bath and kitchen facilities comprising an independent, self-contained dwelling unit within or attached to a single-family dwelling or in a detached building on the same lot. Under VMC 20.810.040 and consistent with RCW 36.70A.681, up to two ADUs may be created on each legal lot containing a single-family residence. Maximum gross floor area is 1,000 square feet per ADU. ADU additions and detached structures must respect the underlying zone's lot-coverage maximum and may not encroach into the setbacks required for the primary structure. For new detached ADUs the applicant submits the Residential New Construction form plus the ADU Supplemental form; for conversions/additions the Residential All Other form plus the ADU Supplemental form are used. Submittals include a scaled site plan, floor plans, elevations, Washington State Energy Code (WSEC) compliance forms, and structural plans. Existing garages or other outbuildings may be converted to ADUs under VMC 20.810.060. Permits flow through Community and Economic Development at 415 W 6th Street, and decisions on complete applications fall under RCW 36.70B.080 timelines.