Washington landlords can terminate a month-to-month tenancy with a notice to the tenant requiring the tenant to vacate at the end of a month, served at least twenty days in advance. No notice is required at the end of a fixed-term lease unless the lease contract terms require notice or automatically trigger a month-to-month tenancy at the end of the lease term. This is the law even in Seattle, where a residential landlord is required to have just cause to end any tenancy.
Tacoma has a different set of rules under laws enacted in 2019. Landlords must give sixty days to terminate a month-to-month tenancy. Also, the landlord must give notice at least sixty days before the end of the lease terms. Under some circumstances, landlords are required to give 120 days notice.
These rules do not apply to commercial tenancies. A commercial landlord may give only twenty days notice and are not required to give notice prior to the end of a fixed-term lease (unless the contract terms require it).