The percolation test hole shall be dug with horizontal dimensions of from 4 to 12 inches and vertical sides to at least 14 inches into the soil layer specified in Env-Wq 1007.02.
N.H. Admin. Code § Env-Wq 1007.04
(See Revision Note at chapter heading for Env-Wq 1000) #9086, eff 2-9-08