All right so I entered into a lease agreement with this second party. Well this second party has become a nuisance. Late nights multiple times per week, has not paid rent for two months, and I have another ten months on this lease. I have a feeling I am stuck, if there wasn't a written agreement prior and doesn't pay her rent for the next ten months and I cover her expense can I sue her? Or can she basically live there for free? Washington state. I am logging everything.

You haven't said if you are the owner of the property or a tenant who has sublet a portion of the property.

In any case, if she hasn't paid rent then you give her a written notice that she must pay the rent within 3 days or move out. If she doesn't pay or move out within that time then you file a lawsuit for eviction. You can do so even if you are not the owner of the property, as long as her agreement is with you and not the owner of the property. (In this situation you would be the sublandlord and she is the subtenant.)

This is a good site that explains landlords' and tenants' rights and remedies in Washington. http://www.google.com/url?sa=t&rct=j...,d.dmg&cad=rjt

Why would you think you are stuck? You are this person's landlord (assuming you entered into the agreement with her and the agreement is not directly with the landlord). There are laws to protect landlords. As soon as she was one month late, you should have given her a pay or quit notice as Lisa advised. It may take time to get her out but you can get her out.

Did you get a security deposit? Did you check her references? Do you know where she works or banks? As part of the eviction you should ask the court to award you damages so you can collect on what she owes.