Abstract: A subterranean coupler for slidably receiving a pipe therethrough and for coupling the pipe to a subterranean vessel. The coupler is mountable to a reinforcing grid prior to the coupler and reinforcing grid being cast in a concrete wall of the subterranean vessel. The coupler includes a longitudinally-extending axis and a cylindrical wall defined about the axis, the wall having an inner surface, an outer surface, and first and second ends. The coupler further includes a plurality of radially-extending, circumferentially-spaced engagement members integrally-formed with the outer surface. The engagement members are engageable with grid members of the reinforcing grid to mount the cylindrical wall to the reinforcing grid prior to casting.