- (a) Trenches constructed within 10 feet of large trees or dense shrubbery shall have at least 12 inches of crushed stone or crushed gravel beneath the leach pipe.
- (b) All trenches shall have a 6 inch layer of septic sand below the crushed stone or crushed gravel.
- (c) The trench thickness shall consist of a minimum of 12 inches of stone total, with minimum of 6 inches of stone under the 4 inch diameter pipes, and a minimum of 2 inches of stone over the pipes.
- (d) The bed bottom shall be the bottom of stone in the trench.
Source. (See Revision Notes #1 and #2 at chapter heading for Env-Wq 1000) #11184, eff 10-1-16; ss by #14486, eff 2-1-26, EXPIRES: 2-1-36