King County, WA Rental Property Rules: Just Cause Eviction (2026)

Just cause eviction is one area where Washington state law permits and mandates local tenant protection, carved out from the rent control preemption. The 2021 state Residential Landlord-Tenant Act amendments (RCW 59.18.650) provide that a landlord may not terminate a month-to-month tenancy without one of the enumerated just causes. Permitted causes include: tenant nonpayment of rent (14-day pay-or-vacate notice), material lease violation after warning, substantial waste or nuisance, use of premises for unlawful purpose, refusal to allow lawful entry, tenant has been convicted of certain crimes on premises, landlord is removing the unit from the rental market, owner or immediate family member is moving in, landlord is performing substantial rehabilitation, demolition, or conversion, and a limited set of other reasons. Required notice periods vary: 14 days for nonpayment, 30 days or more for most no-fault reasons, and 20 days for month-to-month termination under a permitted cause. King County, through Ordinance 19340 (2021), extended and strengthened just-cause protections in unincorporated King County. Seattle and several other cities within King County have their own just-cause ordinances that may be stricter. A landlord who attempts to evict without just cause is subject to tenant defenses in unlawful detainer actions and may owe damages, attorneys fees, and up to three months rent under RCW 59.18.650(6).