The walls and floors of your home hide a complex network of wires and pipes.

Most people don’t understand this complex network, and have no desire to! However, we know that you, as a budding-DIYer, want to understand what’s going on behind the scenes of your home.

It’s a good thing you’re here because your home’s DWV plumbing system is one of its most important components.

What is the DWV System?

DWV stands for Drain-Waste-Vent. Your home’s Drain-Waste-Vent plumbing system is the collection of pipes that rid your home of sewage and water waste from toilets, bathtubs/showers, sinks and appliances like dishwashers and washing machines.

There are two parts to the DWV plumbing system: drain-waste pipes and vent pipes. Drain-waste pipes take the actual waste from the various drains and appliances in your home, and deliver them to the public sewer or septic tank.

Vent pipes perform two functions. First, they ventilate the sewage gases out of the house, usually by way of an exhaust pipe on the roof. Second, they provide air to the drain-waste pipes, which helps the sewage drain smoothly and silently (without gurgling noises).

While each home’s DWV system will have a slightly different layout, most DWV systems follow a basic pattern. Usually, there is one vertical pipe (often called a “stack”) that runs from roof to basement, and connected to the main stack are multiple horizontal pipes at each level of the home.

These horizontal pipes drain the various sinks, toilets, showers, appliances, etc. Each horizontal pipe slopes down from the drain to the vertical pipe, to avoid clogs and stagnant water.

Why Should You Care?

First off, your DWV system is a vital part of your home! Without it, you’d very quickly have a home bursting to the seams with sewage and waste water. Yuck!

Drain-waste and vent pipes are the unsung heroes of modern civilization. Drain-waste pipes keep your home clean and sanitary, and vent pipes keep sewage gases from building up in your home. This is especially important, because some sewage gases, like methane, not only stink, but are poisonous as well!

Second, even just a rudimentary understanding of the DWV plumbing system can help you deal with issues like clogged pipes and drains.

Once you understand the basic layout of a DWV system (vertical stack with multiple horizontal drain pipes attached), you can more easily find the sources of clogged drains. For example, if a sink in the basement is not draining properly, you can rest assured that the pipes on the second floor are not the issue!


A large part of the path to DIY-mastery is simply knowing what you’re dealing with. Now that you know what your DWV system is, you’re well-prepared to learn how to test it! You’ll learn that on the next blog or visit PlugAll™ out more about this new DWV mechanical test plug.

See you there!