(a) Except as allowed in (c), below, each bed that includes concrete chambers shall be constructed on a 6 inch level layer of:
- (1) Medium to coarse textured sand, with an effective size of 0.25 to 2.0 mm or number 60 sieve to number 10 sieve, no greater than 5% passing the number 200 sieve, and no particles larger than 3/4 inch; or
- (2) Materials meeting the ASTM C-33 specification.
- (b) Except as allowed in (c), below, for a concrete chamber system the bed bottom shall be the bottom of the concrete chamber.
- (c) A 6-inch layer of septic stone may be placed under the chambers provided that the sand requirement in (a) is placed under the stone and able to be viewed at the time of inspection. The bed bottom shall be the bottom of the stone.
- (d) Minimum of 3 inches of septic stone is required to be placed on the exterior sides of a concrete chamber bed, and filter fabric or galvanized wire mesh shall be placed on the exterior sides of a concrete chamber bed prior to placing the septic stone.
- (e) The pipe conveying effluent from the septic tank to the bed shall empty into either a velocity reducing pit, a splash plate, or internal distribution system.
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