For isolating the wetwell of submersible nonclog pumping stations for maintenance purposes, a sluice gate of the nonrising stem type (with a two-inch square nut operator in a flush floor box to enable operation from the top of the wetwell using a T-wrench) shall be provided inside the wetwell on the influent pipe. Stem guides shall be provided as required.

For isolating the wetwell of submersible grinder pumping stations for maintenance purposes, a direct-buried eccentric plug valve (with a two-inch square nut operator in a valve box flush with grade to enable operation from ground level using a T-wrench) shall be provided adjacent to the wetwell on the influent pipe. (Design Guideline DG-08 § 5.4, dated August 2006)