1 1/2 or 2 inch. 2 inch is better because it give more venting for the drain.
The proper size minimum size is 2" and ideally there would be an air break which is not always practical with a 2" stand pipe.The "vent" is installed AFTER the trap to prevent air locks and 2" is used to allow the Volume to flow freelyCopyright © 2026 eLLeNow.com All Rights Reserved.
