14 CAR § 20-109. Supply line and manifold

(a) The supply line and manifold should be designed with a flow velocity between: (1) Five-tenths feet (0.5’) per second; and (2) Five feet (5’) per second. (b)(1) The piping and fittings in the supply line and the manifold shall be Schedule 40. (2) Schedule 80 fittings shall be used at the filter system as well as any point where the piping will be disconnected or subjected to abuse. (c) When dosing, the supply manifold shall eliminate the drainback potential from a higher to a lower elevation in the drainfield.