I live in Huntington Beach, California. I have a roommate. I offered the room to him below market rates because he is a good friend. I introduced him to my friend. They are now dating. She is also at the house half the time, sleeping over and doing laundry. I need my privacy. I do not want him as a roommate any more. There was no written rental agreement between us. I need to know, by law, can I give him a 30 day notice, or just evict him? What can I legally do to remove him from my house?

He is on a month to month lease with you, if you never discussed duration.

Therefore, you must give him 30 days notice before evicting him.

Yes you have to give him notice.