The connection of the building sewer into the public sewer shall be made by the “Y” branch if it is available at a suitable location. If the public sewer is 12 inches or less in diameter and no properly located “Y” branch is available, the owner shall, at his or her expense, install a “Y” branch in the public sewer at the location specified by the Superintendent. If the public sewer is more than 12 inches in diameter and no “Y” branch is present, a neat hole may be cut in the public sewer to receive the building sewer, with entry in the downstream direction at a 45-degree angle. A 45-degree ell may be used to make the connection, with the spigot end cut so as not to extend past the inner surface of the public sewer. The invert of the building sewer at the point of connection shall be at the same as or a higher elevation than the invert of the public sewer. A smooth neat joint shall be made and the connection made secure and watertight by encasement in concrete. Special fittings may be used for the connection only when approved by the Superintendent.