My question involves a security deposit in the State of: California.

My tenant/roommate moved in on Nov. 1st and told me on Nov. 3rd that he's moving out. He did pay the month's rent and wants to move out on Nov. 22nd. The good thing is I found someone to move in on Dec 1st. Can I keep his security deposit since I had to go through the hassle of looking for a new roommate even though he is paid up on the rent?

Do I also have to give him back the pro-rated rent from Nov. 22nd to Dec. 1st?

Thank you.