Plumbing and drainage used to collect and convey the discharge from a sanitary plumbing system, together with discharge from fixtures directly connected to a drain, to a sewer. Though household sewer and vent lines used to be made of clay, lead or cast iron, current building code regulations dictate that they be made of PVC (Polyvinyl chloride), ABS (Acrylonitrile Butadiene Styrene) and in some areas, cast iron.