No sewer connection to premises may be installed or maintained unless the same is connected directly to the sewer line coming from the buildings on the premises. No connections may be made indirectly to cesspools or septic tanks. Parallel water and sewer lines shall be laid at least ten (10) feet apart horizontally. Where it is necessary for sewer and water lines to cross each other, the crossing shall be made at an angle of approximately ninety (90) degrees, and the sewer shall be located three feet or more below the water line. The superintendent may, in his or her discretion, allow minor variations of the foregoing if he or she finds that it is uneconomical or practically impossible to comply with such conditions. Before any backfilling is done in the trench for the sewer on the private property of one making a new connection to the sewer, the recorder shall be notified. The recorder shall notify the superintendent, and no backfilling shall take place until the superintendent shall have made an inspection. If the superintendent desires, he or she may, in his or her discretion, require a test for leakage to be carried out under his or her direction and in his or her presence; and, in such case, the person installing the sewer shall make the test at no expense to the city. Upon completion of the test, any tees or openings in the pipe shall be capped tightly and secures against back pressure. If the sewer is properly installed and the joints are tight, the superintendent shall give written approval of the same. If he or she does not approve it, he or she shall state the deficiencies in writing. (Prior code § 4.106)