many; more than one. .-. I didn't mean toward your sis, but toward the people saying "SHE'S 18 SHE CAN DO WHAT SHE WANTS LAH DERPY YOLO 360 NO SCOPE SWAG
And again… if she's living on someone else buck (water, electricity, etc is not free) then just endure until she.can move.out on her own. Telling your parents your new rules that you want in their house is just going to make things worse.