The City Council adopted CB 120949 on April 30, 2025 to update Seattle’s zoning code for accessory dwelling units (ADUs), bringing local regulations into compliance with Washington State HB 1337. The ordinance allows two ADUs in any configuration—attached or detached—on any lot permitting single-family homes and consolidates ADU provisions into a new SMC section 23.42.022. ADUs up to 1,000 square feet are permitted, with exemptions for up to 250 sq ft of garage area and storage areas accessible only via exterior doors, and attached ADUs within existing structures may exceed this size. The bill exempts ADU floor area from FAR limits in Neighborhood Residential zones, applies zone height limits (or 40 ft, whichever is less) to ADUs, and allows up to 50 ft in taller zones. Setbacks align with underlying zone standards, except in NR zones where DADUs may cover 60% of rear yards and must be separated from principal structures by at least 5 ft. The ordinance also waives parking requirements and street improvement obligations for ADUs and enables condominium ownership. Implementation details include no alley setbacks, director flexibility on conversions, and consistency across all zones where single-family homes are allowed.