(a) Without special permission in writing from the City Engineer, no person shall be permitted to tap any sewer of the City or make any connection therewith, unless there shall be installed in such connection, or in the house sewer, what is commonly known as a back-water valve, in order to prevent the back-flow of water from such sewer.
(b) The Director of Public Service shall designate and approve the standard acceptable types of back-water valves that shall be used and promulgate rules covering the conditions where the back-water valves shall be used.
(c) The installation of back-water valves shall be subject to the approval of the Plumbing Inspector.
(d) Whenever the Director of Public Service shall determine it necessary, all owners of property which is now connected with City sewers shall install back-water valves in the sewer connections to their property, subject to the approval of the Plumbing Inspector.
(e) No owner or occupant of property, having a sewer connection without a back-water valve, who is ordered to install the back-water valve therein shall fail to comply with such order.