Question: About a year ago I found out that a casual friend had been laid off and become homeless. I let him move into my apartment's spare bedroom free of charge. Now I want my privacy back. I have asked him to leave, but he doesn't appear to be making any effort to do so. A real estate agent says my friend is a trespasser, since we have no rental agreement or landlord-tenant relationship. She says I can call the police to have him removed or I can change the locks on a day when he is away. I don't want to get into any trouble, so I am writing to ask what my legal rights are.
Answer: You allowed this person to move into your property with your permission, so he is not a trespasser. An adult living in a rental property without paying rent or being party to a rental agreement, oral or written, is consider a "tenant at will."
Since the law regards him as a tenant, he cannot be locked out or forcibly removed. Your only legal avenue is to give him a written notice of termination of tenancy. If he doesn't leave voluntarily after receiving written notice, you can file an eviction lawsuit, known as an unlawful detainer, in court. Because he is a tenant at will, you need only give him a 30-day written notice to vacate, rather than the 60-day notice that would be applicable to a traditional month-to-month tenancy of more than a year.