Modern Plumbing Systems
In modern plumbing, a drain-waste-vent (or DWV) is part of a system that removes sewage and greywater from a building, and regulates air pressure in the waste-system pipes to aid free flow. Waste is produced at fixtures such as toilets, sinks, and showers, and exits the fixtures through a trap, a dipped section of pipe that always contains water. Overview DWV systems maintain neutral air pressure in the drains, allowing free flow of water and sewage down drains and through waste pipes by gravity. It is critical that a sufficient downward slope be maintained throughout, to keep liquids and entrained solids flowing freely towards the main drain from the building. In relatively rare situations, a downward slope...