§ 52.31  EXCAVATION AND CONSTRUCTION REQUIREMENTS.
   (A)   No excavation shall be made until a permit for the connection has been issued by the city.
   (B)   No water service pipe or water connection shall be installed in the same trench or closer than ten feet horizontally to a sewer trench or drain laid, or to be laid, either in the street or in private property, except that the water pipe on private property may be in a common trench with a sewer drain which is of a material that is in conformance with the current Minnesota Plumbing Code, Minn. Rules Ch. 4715, as it may be amended from time to time.
   (C)   Where it is desired to lay the water service pipe and the building sewer pipe in the same trench, or in separate trenches less than ten feet apart, the water service pipe shall be above the sewer pipe unless approved by the City Engineer.  It shall be placed at least one foot above the sewer and on a solid shelf excavated at one side of the trench.  The sewer pipe shall be of a material that is in conformance with the Minnesota Plumbing Code with tested watertight joints.  The water service pipe shall be watertight and corrosion resistant.  Copper pipe and ductile or cast iron water pipe with specially protected joints is acceptable for this construction.  Cast iron pipe shall conform to the American Water Works Association specifications for this pipe.  Bell joint clamps with rubber gaskets are provisionally acceptable as extra protection for the joints on cast iron water pipe.  In all cases, precautions shall be taken to assure a firm foundation for the pipes.  The intervening space between the pipes shall be backfilled with compacted earth.
   (D)   In case the installation is on a surfaced street, the following shall apply:  All backfill materials shall be mechanically compacted in 12-inch layers to the density of the adjacent material in the roadway area and to the existing street grades in accordance with the Minnesota Department of Transportation Standards.  Complete surface restoration shall be made.
Penalty, see § 10.99