All excavating required for the installation of a building sewer shall be open trench work unless otherwise approved by the Superintendent. Pipe laying and backfill shall be performed in accordance with rules and regulations of the city. No backfill shall be placed until the work has been approved by the duly authorized city official. Tunneling may be permitted but no tunnel shall exceed six feet in length and the pipe shall be installed so as to permit inspection of all joints.
(1997 Code, § 19.17) Penalty, see § 52.999