How often should a plumbing vent be installed in a horizontal run?

The correct guideline for installing a plumbing vent in a horizontal run is every 10 feet. This requirement is based on plumbing codes and practices, which state that vents should be placed at regular intervals to ensure proper air flow and drainage. Proper ventilation is crucial for allowing sewer gases to escape, preventing vacuum conditions that could disrupt drainage, and facilitating effective waste flow.

By installing vents at 10-foot intervals, you create a balanced pressure within the plumbing system, which helps maintain water seals in traps and avoids potential issues such as siphoning, where trap water can be drawn out, leading to odors and blockages. This interval also minimizes the likelihood of pipe material sagging or causing blockages due to improper slope or alignment.

Understanding this interval is essential for maintaining compliance with local plumbing codes and ensuring a functional and safe plumbing system.