AskCodeMan

How far from a vent stack can the kitchen drain be located?
Thank you,
Garrett

The answer depends on the size of the pipe from the trap to the vent, the pipe is required to slope 1/4 inch per foot for 2 inches and smaller, which means smaller pipe must be shorter in length to allow the pipe to remain open and vented.
- 1-1/2 inch pipe is allowed to have a maximum distance of 6 feet from the weir of the trap to the vent.
- 2 inch pipe is allowed to have a maximum distance of 8 feet from the weir of the trap to the vent.

3 inch and 4 inch pipe are allowed greater distances, not only because they are larger in size, but also because their slope is only required to be 1/8 inch per foot, but you would not have pipe that size for the kitchen drain.

Keep in mind that if you slope a pipe greater than the 1/4 inch per foot, or greater than the 1/8 inch per foot, the allowable distance is going to become considerably shorter the more the pipe is sloped.