All water, sewer and gas pipes and other conduits and mains shall be laid on a layer of sand or stone dust at least four inches in depth, and then filled with the same to a depth of six inches above the top of the pipe, with a side cover of at least four inches. All excavations in the traveled portion of public streets and alleys shall be filled and tamped with clean coarse gravel to the street level and made passable for traffic. In grass plots or nontraffic locations, the trench may be filled with the earth or material removed and then tamped. All coarse or lumpy earth shall be pulverized before placing it in the trench. All grass plots shall be replaced to their original condition.
(`94 Code, § 925.05) Penalty, see § 10.99