The Residential Landlord-Tenant Act of Washington sets out the conditions under which a landlord or tenant must give notice to the other party, the information that must be included in the notice, the length of the notice period for each condition, and the way in which the notice must be served.
The most common reasons for giving notice are to terminate the tenancy (given by either party), to report a condition that needs repair or maintenance (given by tenant), to demand payment of outstanding rent (given by landlord or rental manager), and to give notice that the other party is in default of its obligations (given by either party).