Renting out a room but not on lease, can I break it?

[angelzatwar]

I am not on the lease but the woman who is letting me rent out the room in my apartment has a written agreement on a month to month rent. I paid for this month's rent, but is it possbile for me to up and leave without the full 30 days notice? I let her know earlier this month on the 4th through email, but she still wants a written notice and wants me to pay for next month's rent since it wasnt a full 30 days. I beleive she is "illegal subletting", but I dont want to have to go to court for not paying her for next month's rent. Can I just leave?

[angelzatwar]

also, how late can i give her the notice in the state of California?

[OHlandlord]

Without a written agreement with her, you are also considered a month to month tenant. In the state of CA, you must give her 30 days written notice to vacate and pay her for that period. If you vacate and she re-rents your room during that 30 day period, you are entitled to a refund prorated for the number of days that someone else lived there.