(A)    All materials and practices shall conform to applicable City and State building codes and to Utility requirements and regulations. Any and all work done is subject to approval of the Utility Operations staff.

    (B)    Whenever feasible, the building sewer shall be brought to the building at an elevation below the basement floor. No building sewers shall be laid parallel to or within three feet of any bearing wall which might be weakened. The depth shall be sufficient to afford protection from frost. The building sewer shall be laid at a uniform grade and in straight alignment. Changes in directions shall be made only with properly curved pipes and fittings. In all buildings in which any building drainage is too low to permit gravity flow to the public sewer, sanitary sewage carried by the drain shall be lifted by approved artificial means and discharged to the building sewer.

    (C)    Drainage piping serving fixtures which have flood level rims located below the elevation of the next upstream manhole cover of the public sewer serving such drainage piping shall be protected from backflow of sewage by installing an approved type backwater valve. Fixtures above such elevation shall not discharge through the backwater valve.

(’ 82 Code § 50.48)