HOW TO DEAL WITH BAD LANDLORD AND BREAK THE LEASE?

I found out the apartment I rented was not supplied with clean water. The water came out of the tap look like yellow mud. The water department told me that the pipe from the meter down to my apartment was using an iron pipe. I called up the landlord and ask him to fixed it but he was unwillingly to fix the problem because it would cause him money. I wanted to break the lease and move out and he won't accept it. Can anyone tell me what can I do about this?