§ 15.01.780. Culinary water line construction near sewer or wastewater lines.

(Applicable public health department criteria)

A.

Water/sewer line horizontal separation. A culinary water main must be laid at least ten feet horizontally from any existing or proposed sewer or wastewater leach line. Separation distances shall be measured pipe edge to pipe edge.

Should local conditions prevent a lateral separation of ten feet, a culinary water main may be laid closer than ten feet to sewer lines (but not leach lines) provided:

1.

The main is laid in a separate trench; or

2.

The main is laid on an undisturbed earth shelf on one side of the sewer line trench; or

3.

The main is laid in a sewer or drain line trench which has been backfilled and compacted not less than ninety-five percent of maximum laboratory density. (The density shall be determined in accordance with the procedures given by ASTM Standard D-690).

In each of the above cases, the bottom of the culinary water line shall be at least 18 inches above the top of the sewer line. At the same time, the culinary water line must be sufficiently buried to prevent freezing.

B.

Exception to horizontal separation. When it is impossible to obtain the proper horizontal and vertical separation as stipulated above, both the water main and sewer line shall be constructed of cast iron, ductile iron, galvanized steel or protected steel pipe having mechanical joints. Other types of joints of equal or greater integrity may be used at the discretion of the city engineer. Thermoplastic pipe may be used provided mechanical or solvent weld pipe joints are used. These lines shall be pressure-tested to assure water tightness before backfilling.

C.

Culinary water/sewer line crossings. Whenever culinary water mains must cross sanitary sewers, the water main shall be laid at such an elevation that the bottom of the water main is eighteen inches above the top of the sewer. This vertical separation should be maintained for the portion of the water main located within ten feet horizontally of any sewer it crosses. The ten feet is to be measured as the perpendicular distance from the sewer line to the water line.

D.

Inability to provide vertical separation. Where conditions prevent the minimum vertical separation as set forth above from being maintained, or when it is necessary for the culinary water main to pass under a sewer, both the culinary water main and the sewer line shall be constructed of cast iron, ductile iron, galvanized steel or protected steel pipe, having mechanical joints. Thermoplastic pipe may be used provided mechanical or solvent weld type joints are used. The mechanical joint pipe shall extend on each side of the crossing until the perpendicular distance from the sewer line to the culinary water line is at least ten feet. In making such crossings, it is preferable to center a length of culinary water main so that the joints will be equidistant from the sewer and as remote there from as possible.

Where a culinary water main must cross under a sewer, a vertical separation of at least eighteen inches between the bottom of the sewer and the top of the culinary water main shall be maintained with adequate support for the larger sized sewer lines to prevent them from settling on and breaking the culinary water main.

In the case where a new culinary water line must be routed under an existing sewer line, and it is desired not to disturb the sewer line, the city engineer may grant an exception to the above requirements. The designer must then propose a method for protecting the culinary line. Such a proposal must be deemed acceptable in writing by the city engineer.

(Ord. No. 2007-07-31, §§ 9.8—9.8.4, 7-10-2007; Ord. No. 2010-11-24, § 2, 11-23-2010)