What Is a Drain Stack?

How Drain Stacks Work

Every drain leading from your sinks, showers, toilets, and other plumbing appliances drains onto the central vertical pipe known as the drain stack. This makes the drain stack extremely important for day-to-day plumbing operation, and a major problem for your home if anything goes wrong with it.

The pipes leading to the drain stack have what is called a “U-bent.” The U shape of these pipes let water fill in at the bottom. This water then seals odors traveling through the drain stack from entering your home. In most California houses, the drain stack vents through the roof. However, homes that use extremal venting can experience severe drain stack problems if they are surrounded by trees and greenery, as the vents may become clogged by leaves and debris, preventing them from getting rid of wastewater. Call a plumber if you notice slow drains in your home, as this may indicate problems with your drain stack and external vents.