As the wastewater flows out and into the main sewer system, the water will pass a number of clean outs. There is a cap that covers the stem. The purpose of these clean-outs is to provide access for drain cleaning equipment if there is a clog in the wastewater system. The different systems in your house require different kinds of pipe. Generally, copper tubing is preferred for interior piping because of its ease of installation.
Galvanized pipe is found primarily in older homes.
PVC pipe is not considered to be as dependable as copper or galvanized pipe, and is usually only used for systems that are not under constant pressure, such as sprinkler systems. ABS pipe is the pipe proffered in most new construction because of its low cost and ease of installation. Cast iron pipe, while most often found in older homes, is still used today for more expensive homes because it is quieter than ABS pipe, and therefore you will not hear the sound of water flowing through it. Galvanized pipe is sometimes used in conjunction with cast iron pipe for vents and smaller drain lines. Plumbers use a variety of specialized tools.