In a vertical piping system, which configuration serves as both a vent and a drain?

A wet vent serves as both a vent and a drain within a vertical piping system. This configuration is specifically designed to allow for the proper ventilation of wastewater while simultaneously facilitating its drainage. In a wet venting system, one pipe acts as a pathway for both the air needed to prevent vacuum conditions in the drainage system and the flow of sewage or wastewater, effectively utilizing the same pipe for dual purposes.

This can be particularly effective in situations where space is limited, reducing the number of pipes required and simplifying the plumbing layout. A wet vent typically occurs in scenarios where multiple fixtures are connected to the same drainage system. For example, a toilet and a sink may share a wet vent that allows both drainage and venting without needing separate routes.

Understanding the function of a wet vent is crucial for efficient plumbing design and compliance with plumbing codes, ensuring that systems are both effective and safe.