A. Material. The building sewer line shall be of such material as may be required by the authority or the City in its subdivision regulations or other requirements.
B. Size and slope. Size and slope of the building sewer shall be subject to the approval of the authority, but in no event shall the diameter be less than four (4) inches; slope of such pipe shall be not less than one-eighth (1/8) of an inch per foot.
C. Joints and connections. All joints and connections shall be made according to the specifications established by the authority or the City.
D. Excavations, pipe laying, and backfill. All excavations required for the installation of the building sewer shall be open trench work unless otherwise approved by the authority. Pipe laying and backfill shall be performed in accordance with City specifications except that no backfill shall be placed until the work has been inspected.
E. Building sewers. Whenever possible, the building sewer shall be brought to the building at an elevation below the basement floor. No building sewer shall be laid parallel to, or within three (3) feet of, any bearing wall which thereby might be weakened. The depth shall be sufficient to afford protection from frost. The building sewer shall be laid at uniform grade and in straight alignment insofar as possible. Changes in direction shall be made only with properly curved pipe and fittings.
F. Lifts. In all buildings in which any building drain is too low to permit gravity flow to the public sewer, sanitary sewage carried by such drain shall be lifted by approved artificial means and discharged to the building sewer.