In Seattle a residential tenant may only be evicted for “just cause”. The just causes are enumerated in a city ordinance. A landlord may evict a tenant in a residential tenancy in Seattle for only those causes enumerated. A month-to-month tenant is essentially a tenant in perpetuity.
A decision by the Washington Court of Appeals in 2000 held that this does not apply to leases that expire at the end of their terms. The court reasoned that the tenancy ended by mutual agreement and the just cause eviction ordinance could not apply to a tenancy that no longer existed.
So, if a residential lease does not have a clause automatically converting it to month-to-month at the end of the lease the landlord may evict so long the parties do not extend the tenancy by tender and acceptance of rent beyond the lease term or other action indicative of a mutual intent to continue the tenancy beyond the expiration of the lease.
