What Is the Standard Distance From the Wall for a Kitchen Trap?

Kitchen Trap

• In your kitchen, the sink drain empties into a curving section of pipe known as a trap. Shaped like the letter “U,” the trap uses gravity to keep water inside the lowest portion of the curve every time you run the kitchen faucet. The water sits in the bottom of the trap and acts as a waterproof seal against sewer gas. The gas can flow up the drainpipes in your home and out through the drains. The kitchen trap makes sure your home and your family are safe from the negative effects of sewer gas. Typically, the drain trap is less than a foot away from the wall or the back of the kitchen cabinet.

Code Requirements

• Kitchen sinks can be located along a wall, but they might also be located in an island in the center of the room. The distance from the trap to the wall is not dictated by plumbing code as much as the distance from the kitchen trap to the vent pipe. The vent pipe usually runs to your home’s ceiling. It releases sewer gas safely up into the air. The presence of the vent pipe prevents pressure imbalances in the plumbing system from siphoning water out of the kitchen trap. The kitchen trap should be no more than 3 1/2 feet from the vent pipe. In addition, the trap itself should be a minimum of 1 1/2 inches in diameter.

Exceptions

• For a kitchen sink located far from a wall, connected the drain trap to a vent pipe within 3 1/2 feet can be a challenge. One way to get around the issue is to have a separate vent pipe that services only the kitchen. This allows you to place it closer to the kitchen sink. If that isn’t possible, or if the sink is located in an island in the middle of a large kitchen, a loop vent can be used. A loop vent is a section of pipe that arches upward toward the sink, rather than down and away like the trap does. It then connects to the vent pipe.

Considerations

• When remodeling a kitchen, installing a new sink in the exact location as the original is usually safe. If you plan to move the sink, consult with a building inspector before starting work installing the new one. Modifications like installing a loop vent are allowed in some municipalities and forbidden in others. To avoid costly changes in the future, consult with a plumbing professional or building inspector to be sure your plans abide by the code standards for your area.