Accessory Structures in Issaquah, WA (2026)
3 verified accessory structures rules for Issaquah, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Issaquah allows up to two accessory dwelling units, attached or detached, on a lot with a single-family detached home or middle housing. Each ADU is capped at 1,000 square feet of living area, must meet the principal unit's height limit, needs its own address, and goes through Level 1 review under the Land Use Code.
Issaquah Accessory Dwelling Unit (ADU) Rules
Some RestrictionsIssaquah Land Use Code § 18.500.090
C. Review Required. ... An application for an ADU requires a Level 1 review process under IMC 18.204.020 . ... F. Approval Criteria. The following are the approval criteria for an ADU application: 1. Number. Two ADUs, in any combination of attached or detached, may be permitted for one single-family detached residence or with middle housing as long as the lot complies with the allowed lot densi...
Shed & Carport Rules
In Issaquah, an accessory building over 200 square feet of floor area needs a building permit. A detached accessory building in a residential zone is limited to one story and 15 feet, must sit at least six feet from the principal structure, and cannot be placed in a front setback area.
Issaquah Shed and Accessory Building Rules
Some RestrictionsIssaquah Land Use Code § 18.508.030(B)-(C)
B. General Standards for All Accessory Structures. ... 2. Accessory structures must comply with required setbacks, unless specifically excepted below. 3. Accessory structures may not be located in a front setback area. ... C. Sheds, Greenhouses, and Other Accessory Buildings. The following additional standards apply to accessory buildings: 1. Accessory buildings exceeding 200 square feet in flo...
Tiny Homes
Issaquah adopts the 2021 International Residential Code together with Appendix AQ, Tiny Houses, in IMC 16.04.020. The Building Official administers the permits under the Construction Administrative Code in IMC 16.04.010, which separately confirms that Appendix Q, Tiny Houses, is included in the adoption of the International Residential Code.
Issaquah Tiny Houses: IRC Appendix AQ Adopted
Some RestrictionsIssaquah Municipal Code § 16.04.020
The 2021 Edition of the International Residential Code (IRC), as published by the International Code Council and adopted by the State Building Code Council in Chapter 51-51 WAC, excluding Chapter 1, “Scope and Administration,” Chapter 11 and Chapters 25 through 43, is adopted, together with Appendix Chapter AF, “Radon Control Methods,” Appendix AQ, “Tiny Houses,” Appendix T, “Solar-Ready Provis...
Looking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Issaquah city rules.
Accessory Structures in King County →