(1)   Separate systems.  The drainage and plumbing system of each new building and of new work installed in an existing building shall be separate from and independent of that of any other building except where provided in division (2) of this section, and every building shall have an independent connection with a public sewer when it is available.
   (2)   Exception.  Where one building stands to the rear of another building on an interior lot and no private sewer is available or can be constructed to the rear building through an adjoining alley, court, yard or driveway, the building drain from the front building may be extended to the rear building and the whole will be considered as one building drain, where a building drain is nearer the rear wall of the front building.
(Prior Code, § 402.06)