Sammamish, WA Fence Regulations: Neighbor Fence Rules (2026)

Sammamish's fence code addresses neighbors mainly through its height-exception process. Under the Residential Fences handout (No. 220) and SMC 21.06.010.E, a property owner who wants a fence taller than 6 feet, up to the 8-foot maximum, along a side or rear lot line shared with a separately owned property must first reach an agreement with the adjoining owner. That agreement, together with a site plan and a maintenance agreement, must be recorded with King County Records before the City issues the building permit. The same recorded-agreement mechanism appears in the accessory-structure rules, where reduced side and rear setbacks require a recorded agreement under SMC 21.04.030.C.19. The City does not, however, impose a blanket statute making adjoining owners split the cost of an ordinary boundary fence; cost-sharing for a typical 6-foot line fence is a private matter between neighbors, governed by Washington common law and any voluntary agreement, not by a specific Sammamish ordinance. Disputes over fence location, encroachment, or trees are civil matters; the City's role is limited to enforcing height, location, sight-triangle, and permit rules.