PVC is a a white or gray hard plastic, and is currently the most common material for the installation of household sewer pipelines. Pipe sections typically come in 8- or 12-foot lengths, and have a diameter range of 1 1/2 to 4 inches to fit different water fixtures. The pipes join together with PVC couplings, primer and cement. Couplings coming in 30, 45, 60, 90 and 180-degree (straight) angles. Tee couplings are also used to join one pipeline to another.
ABS (Acrylonitrile Butadiene Styrene) is a hard black plastic, available in the same lengths and diameters as PVC. Unlike PVC, no primer is needed to seal the joints, but ABS cement must be used. Whether PVC or ABS is used for a home's sewer system depends on local building code regulations. These two types of sewer pipe must never be used in the same line as they have different expansion rates.
Cast Iron Pipes
Cast iron is so durable that it has been used for centuries for sewer lines, with some of those original pipes still in use today. Due to its weight and installation cost, cast iron is less popular than PVC or ABS, but its thick walls shield any noise from the flow of waste water. Where the pipe sections were once joined together with oakum and melted lead, today the joints are created with a rubber gasket and stainless steel sleeve.
P-traps have a U-shaped bend that is filled with water to stop sewer gases from traveling back up the pipeline and into the home. One side of the trap attaches to the vertical pipe running down from the sink or tub drain hole, and its other end joins to the sewer line. The traps are most commonly made from either PVC or ABS, but where they are visible they can also be chrome plated or made from rough or polished brass.