Legal Question in Family Law in California

This isn't really about the person being your child, they're legally an adult and your not required to support them. However in this case as a tenant you have to give notice. For not paying rent you can give them a 3 day Notice to Quit. Meaning they have 3 days to either pay or leave.

If the tenant pays, you'll have to give more notice to terminate the agreement. When a tenant is not in breach (has been paying) and has been a tenant for more than a year its 60 days notice. if less than a year then its 30 days notice.