What is the primary function of a plumbing vent?

The primary function of a plumbing vent is to allow air into the plumbing system. Vent pipes connect to the drainage system and extend vertically through the roof, providing the necessary air supply that ensures the flow of wastewater and allows for proper drainage. When wastewater moves through the pipes, it creates a vacuum. Without proper ventilation, this vacuum could impede the efficient flow and potentially cause slow drainage or gurgling noises in the fixtures.

When air is introduced into the system through the vent, it equalizes the pressure within the pipes, preventing negative pressure that can lead to slow drainage or even siphoning of water from traps, which would allow sewer gases to enter living spaces. Overall, the ventilation system is crucial for the optimal operation of plumbing systems, balancing pressure, and maintaining hygiene by directing sewer gases outside of buildings.