DWV System. Drain-Waste-Vent

When you turn the faucet off and the water flows down the drain in your sink or you flush the toilet, the waste needs to go somewhere and the pipes that carry these liquids and solids away from you home are called the drain , waste or drain waste vent (DWV) system.

To make sure waste gets to where it’s going, this system of pipes with large diameters has three important components. Like the name implies, the drain lines carry the water away from the showers, tubs and sinks. The waster line takes care of what needs to leave your home from the toilets and the sewer gasses are vented through the aptly named vent lines. These lines also provide air pressure so wastes can flow freely.

Simple is best here and engineering these systems takes advantage of gravity in that both the waste and drain lines slope away from the fixtures to sewer lines or septic systems as the case may be. The right diameter is also important so that there are no blockages. Toilets generally get the largest soil stacks at 10.2 cms, while showers usually have  5.1 cms pipe and other fixtures that carry water like bathtubs, sinks and laundry tubs have pipes with a 3.2 to 5.1cm diameter.

These pipes carry the waste water to vertical stacks whereby vents carry gases to upper portions where they escape through the roof. Another critical aspect of your plumbing and sewer system is what’s called the trap. This U-shaped section of pipe under fixtures serves an important role in that the trap holds water even when the fixture is empty. This water forms a seal that keeps any sewer gasses that are leaving from entering the house.

Homewowners can make sure everything is running smoothly through the cleanouts on the stacks and main drains. These offer access for unclogging the drain system when needed. 

Of course water and waste leaving your home is only part of what you need to concern yourself with. Relying on the right system to get fresh clean water into your home in just as important and the main supply line is controlled by a main shutoff value in the basement.

and an underground curb valve outside your home. Once the water make its way in, it goes past the water meter that tells your municipality how much you use and then gets divided into hot and cold lines that lead to the corresponding fixtures inside your home.