King County, WA Building Safety: Door Locking Hardware (2026)

King County's building security code, K.C.C. 16.10.050, bans using manually operated flush bolts as a substitute for a dead bolt lock on regulated dwelling doors. The dead bolt must open from the inside without a key or tool and must be mounted no more than 48 inches above the finished floor. The chapter applies to apartment houses, rented or leased dwellings, one- and two-family homes, and townhouses, plus openings between attached garages and dwellings, per K.C.C. 16.10.020. This is county code for unincorporated areas only; Seattle, Bellevue, Kent, Renton, Federal Way and other incorporated cities enforce their own building codes.