(1)
Drainage pipes that serve a water closet shall be not less than NPS 3.
(2)
Branch and building drains downstream of the third water-closet fixture drain connection shall be not less than NPS 4.
(3)
Stacks that serve more than 6 water closets shall be not less than NPS 4.
(4)
Discharge pipes serving a macerating toilet system shall be not less than NPS ¾.
(5)
No vertical leg of the drainage pipe from a water closet or other fixture that has an integral siphonic flushing action shall exceed 1 000 mm.