what is a waste pipe?
Drain-waste-vent (DWV) pipes carry waste and water out of the house without gurgles or fumes. Never install or replace a DWV pipe without consulting a building inspector. These pipes must be installed according to precise specifications. Drainpipes. The centerpiece of a DWV system is the main stack, usually a pipe 3 or 4 inches in diameter that runs straight up through the roof. A secondary stack, perhaps 2 or 3 inches in diameter, serves a branch of the system.