How long before a guest is considered a tenant?

Whether a guest becomes an unauthorized tenant is a question that often depends upon what the lease terms provide. Many lease agreements state that any guests staying longer than a 2 week period may be considered unauthorized tenants. Others have longer or shorter time periods. If they have stayed for longer than a month, you might ask the tenant to have their guest prove they do not live there by providing current utility bills for their residence. If they cannot, then they are likely trying to live with your tenant and violating the lease. The response would then be to serve a 10-day notice to comply with the lease terms or vacate. You should consult with an attorney to make sure that you have the facts down, and get the notice properly served.