What is the maximum allowable distance from a fixture to the vent stack?

The maximum allowable distance from a fixture to the vent stack is critical in plumbing design to ensure proper drainage and prevent the siphoning of traps, which can lead to the release of sewer gases and odors into the living space. A distance of up to 6 feet is generally accepted as safe for most fixtures.

This distance allows air to flow freely into the plumbing system, maintaining the balance of pressure necessary for proper drainage. If the distance exceeds this limit, the risk of inadequate venting increases, potentially causing slow drainage and issues with the trap seal.

In contrast, shorter distances, such as those listed in the other options, would either not meet the standards in all plumbing configurations or would unnecessarily complicate the layout without providing additional benefit. Therefore, adhering to the 6-foot maximum distance is essential for maintaining a functional and efficient plumbing system.