Washington Lease Termination and Notice Rules

RCW 59.18.200 provides that a month-to-month tenancy 'shall end by written notice of 20 days or more, preceding the end of any of the months or periods of tenancy, given by the tenant to the landlord.' A landlord cannot mirror this 20-day notice without cause — RCW 59.18.650 makes just cause the rule and lists the only permitted grounds, including nonpayment after notice, material lease breach (at least 10 days to cure), waste or nuisance (3 days), good-faith owner or family occupancy (90 days), sale of a single-family home (90 days), and demolition, substantial rehabilitation, or change of use, which under RCW 59.18.200 require 120 days' written notice. Service-member tenants may give shorter notice with qualifying orders.

Under RCW 59.18.650, an end-of-tenancy or refusal to renew without an enumerated just cause is unlawful; the tenant may raise it as a defense to eviction and may recover damages, and where relocation assistance is owed (e.g., demolition or change of use), the landlord owes the tenant the statutory relocation amount.