Renton, WA Accessory Structures: Shed Rules (2026)

Under the Washington State Residential Code (based on IRC, adopted via RCW 19.27 and RMC 4-5-060) one-story detached accessory structures 200 square feet or less, used as tool or storage sheds, playhouses, or similar, are exempt from building permits. Even when exempt from building permits, sheds must still comply with Renton's zoning standards in RMC 4-2-110 for residential zones: minimum 5-foot setback from side and rear property lines, 20-foot front setback (sheds typically prohibited in front yards), maximum height of 15 feet to ridge, and maximum lot coverage including all accessory structures. Sheds with electrical service require an electrical permit and WA Labor and Industries inspection regardless of size. Plumbing likewise triggers a permit. Sheds over 200 square feet require a full building permit with foundation plans, structural details, energy code compliance (when heated), and inspections. Sheds in critical areas under RMC 4-3-050 including wetland and stream buffers along Cedar River or May Creek are generally prohibited without extensive review. HOAs in Highlands, Fairwood, and other neighborhoods may add restrictions on size, color, and material. Sheds on permanent foundations exceeding certain sizes may also trigger property tax reassessment through King County Assessor.