A. Be constructed of commercially fabricated materials, resistant to sewage, specific to this purpose;

B. Be no greater than 3 feet in width, and have an open bottom with the vertical outside dimensions less than 30 inches;

C. To support the load of overburden and sidewall soil;

D. Have slotted or perforated sides to allow sewage to move laterally into the soil, and prevent soil penetration into the chamber;

E. Have the joints secured as recommended by the manufacturer;

F. Be excavated to a width in accordance with the manufacturer’s recommendations;

G. Not be loaded above the natural ground surface. The entire slatted sidewall must be below the original grade, and effluent must be loaded the entire depth of the slatted sidewall;

H. Be backfilled so as not to crush or damage the medium;

I. Have the following size allotments, with a 20% allowable credit reduction in the size of the absorption area: