How do get rid of my roomate who has procrastinated leaving now for six weeks? He is subletting from me because the landlord kept saying she would put him on the lease but never did.
You are a landlord to your roomate, therefore, you need to follow the Washington State residential landlord tenant laws. Here is a good summary of what you, as a landlord, needs to know: http://www.wsba.org/media/publications/pamphlets/landlord-tenant.htm
If there is no sublease written agreement, your roommate is a month to month "at will" tenant, but is still protected by the law that provides rights to tenants. Make sure you follow the law closely. Here is a link to the Washington law:
Oftentimes the simple 20 day advance notice that is required to terminate a tenancy will be all that it takes as the tenant will get the message. In your situation it will lead to a bit of discomfort, to say the least.
You might also find a good self-help book of forms in the Tacoma Public Library. Good luck.