Are vents necessary?
Plumbing vents are an important part of plumbing drainage systems. The typical household vent and drainage system features two interconnected piping systems. One systems takes water away from fixtures and pushes it toward a septic or sewage system, while the other provides each fixture with air. An interconnected drainage system could not function without vents. Just about every home in America is equipped with an interconnected plumbing drainage system.
How do they work?
The drainage system is able to breathe because of the plumbing vents. Sewage is full of awful fumes, and the venting systems allows air to enter the fixtures, resulting in the fumes being directed into the atmosphere rather than into your home. The pipes for the plumbing vents are usually located on the home's roof. This allows the fumes to go straight up into the air, rather than enter windows or other intake devices. In addition to providing ventilation, the plumbing vents also equalize the plumbing system's pressure whenever a toilet is flushed, or water is run in a sink.
Are vents really significant?
Before plumbing vents were invented, people realized that if water was rapidly drained from one fixture, the water located in the adjacent fixture's U-shaped trap would be sucked away, thus leaving the U-shaped trap dry. However, this wasn't a foolproof method because bugs and fumes would soon enter the room. Without vents, fumes would be inevitable. They are necessary in order to keep foul smells from entering the home.