Kitchen Island Plumbing Vent

The common island loop pictured here could become less popular now that the combination waste and vent option is legal again.

Kitchen island plumbing vent. In a wet vent the p trap from the sink runs horizontally into a larger vertical pipe in the sink base cabinet and discharges into a 3 or 4 inch 76 or 102 mm drain line located in the floor. The vent pipe is hidden within the wall. Each method chosen should be verified by the local plumbing inspector. Three ways to vent an island fixture are discussed next.

You don t have the luxury of hiding drain pipes and vents inside the wall. A vent also prevents the drain trap or p trap from siphoning. A regular kitchen sink vent must rise at least 6 inches above the fixture before going horizontal. However the sink is placed further away.

To have a large sink that drains properly you need to keep in mind some basic plumbing principles. Plumbing for a kitchen island sink isn t as simple as installing a sink against the kitchen wall. This next image shows various types of vent piping behind a sink giving you a more accurate idea of what those might look in your own project. Plumbing a kitchen island presents problems for venting because the sink isn t near a wall behind which you can hide the vent pipe.

The island fixture vent the air admittance valve and the combination waste and vent system. One solution is to install a vent that loops under the floor. We want the drain water to flow freely. An island vent plumbing an island sink is challenging.

Because a kitchen island doesn t have a wall to run a vent pipe the vent must be contained within the cabinet. Generally the venting for a sink goes upward in the wall while the drain water flows downward towards the floor but in an island going up is not an option. Plumbing vents a network of pipes that carry air and gas outdoors through a pipe exiting your roof are essential to supply enough air to keep equal pressure in the plumbing system. It can t be vented the same way as a regular kitchen sink.

Therefore a re vent was added to ensure that sewer gasses could escape. Everything needs to be contained within the island itself. As you can see the true vent aligns with the stack just behind the toilet.