15A NCAC 18E .0902      CONVENTIONAL WASTEWATER SYSTEMS

(a)  A conventional wastewater system shall consist of a septic tank and a gravity distribution dispersal field. In addition to the requirements set forth in Rule .0901 of this Section, this Rule shall apply to conventional wastewater systems as defined in G.S. 130A-343.

(b)  In addition to the installation requirements set forth in Rule .0901(g) of this Section, the following shall apply:

(1)           trenches shall be constructed level in all directions with a plus or minus one-half inch tolerance from side-to-side and the maximum fall in a single trench not to exceed one-fourth inch in 10 feet as determined by a device that measures elevation, such as an engineer's level or laser level;

(2)           trenches shall be located not less than three times the trench width on centers. The minimum spacing for trenches is six feet on center;

(3)           trench widths shall be at least two feet, but no more than three feet, and trench depth shall not exceed 36 inches on the downslope side of the trench, except as approved by an authorized agent;

(4)           aggregate used in trenches shall be clean, washed gravel or crushed stone and graded or sized in accordance with size numbers 4, 5, or 6 of ASTM D448. The aggregate shall be distributed uniformly across the infiltrative surface and over the pipe and placed 12 inches deep with a minimum of six inches below the pipe and two inches over the pipe; and

(5)           the laterals shall meet the requirements of Rule .0703(d) of this Subchapter.

History Note:        Authority G.S. 130A-335(e) and (f); 130A-343;

Eff. January 1, 2024.