This ordinance amends the Seattle Municipal Code to fully comply with Washington State HB 1337 by expanding allowable accessory dwelling units (ADUs) in single-family zones from one to two units in any configuration (attached or detached). It adds a new code section 23.42.022 consolidating ADU standards across multiple zones and clarifies development provisions including unit size, height, setbacks, parking, and street improvement exemptions. ADUs are permitted to be up to 1,000 sqft (with certain exemptions), may be located on any qualifying lot, and can now be sold as individual condominium units. Detached ADUs may occupy up to 60% of the rear yard, require a minimum 5 ft separation from the main structure and lot lines, and face no alley setbacks. Attached ADUs larger than 1,000 sqft within existing structures are allowed. The ordinance removes owner-occupancy requirements and parking mandates and exempts ADUs from certain floor area ratio and street improvement rules. It modernizes the code to encourage additional housing supply, simplify review processes, and support multigenerational and affordable housing options.