Washed gravel, free of organics 4in. clear granular (3/16" 3/4") Crushed Stone, washed with no more than 10% fines (material that passes a in. sieve) Max size ¾ inch Sand, coarse min 1/16 in. free of organics, clayey or silty soils Sump Provide sump in soils classified as GW, GP, SW, SP, or GM Sump shall