The permittee must maintain the following vertical separation distances beneath the subsurface area drip dispersal system.(1) There must be at least five feet of soil over any sand or gravel strata.(2) There must be at least one foot of soil over any restrictive soil horizons.(3) There must be at least two feet of soil over any permanent or seasonal saturated zone of groundwater.(4) The executive director may impose alternate separation requirements if necessary to protect human health and the environment.