Yakima, WA Accessory Structures: Garage Conversions (2026)

A Yakima garage-to-living-space conversion is a change-of-occupancy under the 2018 Washington State Building Code (RCW 19.27 + WAC 51-50) — moving from IRC Group U (utility) to IRC Group R-3 (residential). The Yakima Code Administration Division (509-575-6126) issues building, electrical, mechanical, and plumbing permits as required. Code minimums for the converted space include: 7 ft minimum ceiling height (IRC R305), light and ventilation per IRC R303 (8 percent natural glazing of floor area, with operable window area for ventilation), egress windows from each sleeping room per IRC R310 (5.7 sq ft net openable, 24 in minimum opening height, 20 in minimum opening width, 44 in maximum sill height), smoke alarms in each sleeping room, hallway, and on each level per IRC R314, CO alarms outside each sleeping area per IRC R315, separation of attached private garages from the dwelling unit per IRC R302.6 (no longer required after the garage is converted), 2021 Washington State Energy Code (RCW 19.27A) insulation and air-sealing requirements, and structural confirmation that the existing garage slab and walls meet R-3 occupancy loads. If the conversion adds cooking facilities (kitchen with sink, range, refrigerator) and a separate exterior entrance, the converted garage becomes an Accessory Dwelling Unit (ADU) under YMC 15.09.045 — subject to the 1,000 sq ft size cap (which HB 1337 / RCW 36.70A.680 requires Yakima to honor as a minimum allowed size), the matching exterior style/materials requirement, and accessory-structure setbacks (typically 5 ft side/rear per YMC 15.05 Table 5-1). Under WA HB 1337 (RCW 36.70A.680), Yakima cannot require owner-occupancy as a condition of ADU approval, and cannot impose an off-street parking replacement requirement within 0.5 mile of a major transit stop. Outside the transit buffer, Yakima may still require replacement parking under YMC Chapter 15.06 if the garage conversion eliminates the dwelling's required off-street parking. Compliance review is by Yakima Planning Division and Code Administration. The Residential Addition or Alteration Packet (November 2025) lists application requirements: site plan, floor plans, structural calculations, energy code compliance, electrical/mechanical/plumbing details. Permit fees typically range $500-$2,500 depending on scope.