King County, WA Rental Property Rules: Rent Control (2026)

King County and all cities within Washington are preempted by state law from enacting rent control. RCW 35.21.830 expressly prohibits cities, towns, counties, and municipal corporations from enacting, maintaining, or enforcing any ordinance or charter provision that regulates the amount of rent to be charged for residential rental properties. This statewide preemption has been in place since 1981 and has survived multiple legal challenges and legislative repeal attempts. In practice, this means a landlord in unincorporated King County or any city within the county may raise rent by any amount, subject only to (1) the terms of the lease (a fixed-term lease generally locks in rent for the term), and (2) state notice requirements. Under RCW 59.18.140, for month-to-month tenancies, a landlord must give at least 60 days written notice before a rent increase takes effect. For certain assisted-housing situations, 180 days notice may be required. Seattle and other Washington cities have adopted renter protections that go to the edge of what state law allows: just-cause eviction, notice of rent increases beyond state minimums, relocation assistance when increases exceed a threshold, and mandatory information packets. King County itself has enacted some related tenant protections but not rent caps. Washington state lawmakers have introduced rent stabilization legislation in recent sessions; residents interested in rent control should track state-level bills rather than local ones.