DWV

DWV stands for drain-waste-vent, a plumbing system that removes wastewater from buildings and prevents sewer gases from entering living spaces. The system combines three functions: draining used water from fixtures, disposing of solid waste, and venting to the atmosphere to maintain proper pressure and air balance.

The drain and waste portions carry wastewater from fixtures such as sinks, toilets, showers, and appliances toward a building’s main sewer or septic system. The vent portion runs upward to exhaust air and allow air to enter the system, helping to prevent trap siphoning and to facilitate smooth flow. Each fixture is connected to a trap that creates a water seal, blocking sewer gases from entering the living spaces.

In typical installations, horizontal drain and waste lines are sloped to promote gravity flow, with vertical vent stacks extending through the roof. Cleanouts provide access to clear blockages. Common materials for DWV piping include PVC, ABS, cast iron, and sometimes copper or other metals, depending on local codes and environment.

DWV design must comply with plumbing codes such as the International Plumbing Code or the Uniform Plumbing Code in the United States, and equivalent standards elsewhere. Improper venting or insufficient slope can lead to slow drainage, siphoned traps, or sewer odors. Regular maintenance focuses on preventing clogs, checking traps and seals, and ensuring vent terminals remain unobstructed.