Accessory Structures in Sammamish, WA (2026)
2 verified accessory structures rules for Sammamish, Washington, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Within Sammamish's shoreline jurisdiction, SMC 25.07.080(7) allows only one accessory dwelling unit per primary single detached home, caps an attached ADU's floor area at 1,000 square feet unless it sits wholly in a basement or attic, and requires a detached ADU to stay outside critical area buffers and shoreline setbacks with no setback reductions or variances allowed.
Sammamish Shoreline ADU Rules
Some RestrictionsSammamish Municipal Code § 25.07.080(7)
(7) Accessory Dwelling Unit (ADU). Only one accessory dwelling is allowed per primary single detached dwelling unit. An ADU is only allowed in the same building as the primary dwelling unit when the lot is less than 10,000 square feet in area or when there is more than one primary dwelling on a lot. One of the dwelling units shall not exceed a floor area of 1,000 square feet except when one of ...
Shed & Carport Rules
Sammamish lets homeowners skip a building permit for a small tool or storage shed under SMC 16.20.200(2)(a): tool sheds, storage sheds, playhouses and tree-supported play structures qualify as long as the floor area stays at or under 200 square feet and the height stays at or under 12 feet. Anything bigger, or built inside a critical area or shoreline setback, needs a full building permit.
Sammamish Storage Shed Permit Exemption
Light RestrictionsSammamish Municipal Code § 16.20.200(2)(a)
IRC accessory structures used as tool and storage sheds, one-story tree-supported play structures, playhouses and similar uses, but not including vehicle storage, provided the floor area does not exceed 200 square feet and, except one-story tree-supported play structures, the height does not exceed 12 feet from the grade plane to the highest point of the roof.
Looking for King County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Sammamish city rules.
Accessory Structures in King County →