When required by the City, the owner of any property serviced by a building sewer
carrying (or reasonably believed to be carrying) waters and wastes containing prohibited
substances or industrial wastes in excessive concentrations or quantities shall install
a suitable control manhole together with such necessary meters and other appurtenances
in the building sewer to facilitate observation, sampling and measurement of the wastes.
Such manhole, when required, shall be accessibly and safely located and shall be constructed
in accordance with plans approved by the City. The manhole shall be installed by the
owner at his expense, and shall be maintained by him so as to be safe and accessible
at all times.