15A NCAC 18C .0906      RELATION OF WATER MAINS TO NON-POTABLE WATER LINES

(a)  For the purposes of this Rule, sewer shall mean any existing or proposed gravity or force main used to convey sanitary or industrial process waste.

(b)  Lateral Separation of Sewers and Water Mains. Water mains shall be laid at least 10 feet laterally from existing or proposed sewers, unless local conditions or barriers prevent a 10-foot lateral separation, in which case:

(1)           the water main shall be laid in a separate trench, with the elevation of the bottom of the water main at least 18 inches above the top of the sewer; or

(2)           the water main shall be laid in the same trench as the sewer, with the water main located at one side on a bench of undisturbed earth and with the elevation of the bottom of the water main at least 18 inches above the top of the sewer.

(c)  Crossings. A water main that crosses a sewer shall be laid a minimum vertical distance of 18 inches from the outside of the water main and the outside of the sewer, either above or below the sewer, with preference to the water main located above the sewer. One full length of water pipe shall be located so that both joints will be as far from the sewer as possible.

(d)  Water Mains and Storm Sewer Pipes. Pipes carrying storm drainage shall be separated from water lines in accordance with Rule .0904 of this Section.

(e)  Water Mains and Reclaimed Water Distribution Lines. Water lines shall be located at least 10 feet horizontally from or at least 18 inches above water pipes carrying treated and disinfected wastewater in reclaimed water distribution lines. Crossings shall be made in accordance with Paragraph (c) of this Rule.

(f)  Special Conditions. If an engineer demonstrates it is impracticable to maintain the separation distances required by this Rule, taking into consideration feasibility, cost, and the factors set forth in this Paragraph, the deviation may be approved on a case-by-case basis, if supported by data and alternative construction criteria provided by the design engineer. Data and alternative construction criteria submitted by the design engineer to justify the deviation must describe:

(1)           the rationale for determining that separation criteria described in this Rule are impracticable;

(2)           the extent of the deviation from separation criteria in this Rule;

(3)           a consideration of pipe materials, pressure ratings, type of joints for water main and non-potable water line, and soil conditions;

(4)           the ability to provide adequate work space to repair or replace pipe segments or other utility infrastructure without causing damage to or otherwise compromising the integrity of pipes; and

(5)           the rationale for determining that the deviation will not result in unreasonable risk to public health.

History Note:        Authority G.S. 130A-315; 130A-317; P.L. 93-523;

Eff. January 1, 1977;

Readopted Eff. December 5, 1977;

Readopted Eff. July 1, 2019.