who should pay my water bill?

i live in a 2 family flat in hamtramck mi. when i moved in, i was told that i was getting discounted rent (350 for a 2 bedrm) because no utilities were included. ok, i'm only 21 so that sounded good to me. but there is someone who lives up stairs. He pays his own lights. i pay gas and water for the whole house. the week after i moved in, i received a shut off notice for the water. i talked to my LL about this, and he said he'd pay it. 5 months later, it not paid. more than 600 now, which i know i am partially responsible for, even tho the bill was already 400 when i moved in. I don't feel i should be paying the gas alone, and someone told me it was illegal to have me paying water because there was already a past due balance and because its only one meter. help me!!!