Drain-waste-vent, or DWV, is a type of plumbing systems in which sewage is taken from a building and noxious gases are vented. Waste enters the DWV from plumbing fixtures such as toilets, sinks, bathtubs and showers. The waste exits the fixtures through a dipped section of pipe called a trap, which maintains a constant supply of water. All plumbing fixtures must have traps to prevent gases backing up into the home or building, with rather unattractive and unhealthy results.Traps connect plumbing fixtures to a common waste line, which channels waste to what is euphemistically called a soil stack. The waste is then removed from the building through a main drain and taken to a sewage line.The venting system pipes are an important part of any plumbing system. It is their job to connect fixtures directly to the outdoors, often through the roof. Vents serve several purposes; they allow an outlet
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