Section 1150. Separation of water mains and sewers

A. The following factors shall be considered in providing adequate separation of water mains and sewers:

1. Materials and types of joints for water and sewer mains;

2. Soil conditions;

3. Service branch connections into the water main and sewer mains;

4. Compensating variations in the horizontal and vertical separations;

5. Space for repairs and alterations of water and sewer mains;

6. Offsetting of pipes around manholes; and

7. Identification of the physical restraints preventing normal separation.

B. Parallel installation.

1. Under normal conditions water mains shall be laid at least 10 feet horizontally from a sewer or sewer manhole. The distance shall be measured edge-to-edge.

2. Under unusual conditions when local conditions prevent a horizontal separation of 10 feet, the water main may be laid closer to a sewer or sewer manhole provided that:

a. The bottom (invert) of the water main shall be at least 18 inches above the top (crown) of the sewer;

b. Where this vertical separation cannot be obtained, the sewer shall be constructed of AWWA approved water pipe, pressure tested in place without leakage prior to backfilling; and

c. The sewer manhole shall be of watertight construction and tested in place.

C. Crossing.

1. Under normal conditions water lines crossing sewers shall be laid to provide a separation of at least 18 inches between the bottom of the water line and the top of the sewer whenever possible.

2. Under unusual conditions when local conditions prevent a vertical separation described in subdivision C 1 of this section, the following construction shall be used:

a. Sewers passing over or under water mains shall be constructed of the materials described in subdivision B 2 b of this section; and

b. Water lines passing under sewers shall, in addition, be protected by providing:

(1) A vertical separation of at least 18 inches between the bottom of the sewer and the top of the water line;

(2) Adequate structural support for the sewers to prevent excessive deflection of the joints and the settling on and breaking of the waterline; and

(3) That the length of the water line be centered at the point of the crossing so that joints shall be equidistant and as far as possible from the sewer.

D. No water pipes shall pass through or come in contact with any part of a sewer manhole.

Historical Notes

Derived from VR355-18-012.05 § 3.52, eff. August 1, 1991.

Statutory Authority

§ 32.1-12 and 32.1-170 of the Code of Virginia.