Auburn, WA Accessory Structures: Shed Rules (2026)

Under Auburn City Code Chapter 15.36 (adopting the 2021 Washington State Building Code and IRC) and ACC Chapter 18.31 (accessory structures), detached accessory buildings such as storage sheds of 200 square feet or less and 10 feet or less in height are exempt from a building permit. However, all accessory structures regardless of size must comply with zoning setbacks, height limits, and lot coverage rules. Typical residential setbacks: rear and interior side yard 5 feet, front yard per underlying zone (10 to 20 feet for most R zones), street-side yard 10 to 15 feet. Accessory structures cannot occupy more than 50 percent of the required rear yard and combined with other buildings must not exceed the lot coverage cap (typically 35 to 50 percent by zone). Sheds over 200 sq ft, over 10 feet tall, on permanent foundations, or containing plumbing or electrical require a building permit from Auburn Community Development. Structures over 120 sq ft in Lea Hill Annexation (special overlay) may trigger additional review. Critical area buffers under ACC 16.10 restrict shed placement near wetlands, streams, and steep slopes regardless of size. Pre-manufactured kit sheds follow the same rules as site-built.