(A) A separate and independent building sewer and septic tank shall be provided for every building, except that where one building stands at the rear of another 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 sewer from the front building may be extended to the rear building and the whole considered as one building sewer.
(B) Old building sewers may be used in connection with new buildings only when they are found, on examination and test by the Superintendent of Public Works, to meet all requirements of this Chapter.