Need Legal Advice in Roommate Situation?

Each city/county/state is different. On average though once a person moves in and establishes residence then you need an eviction. A lease has no legal foothold unless you were married or something. Once a person stays longer than a certain period of time and / or receives mail they have established residency. So to CYA (Cover Your ETS) go get an eviction letter. Some evictions are as little as 24 hours tto 3 days to 30 days.