3.1.1 The drip tubing or installed trench bottom shall be above the seasonal water table, whatever the duration. Brief seasonal water tables may be minimized or eliminated by the use of effective interceptor drains. Any design, which incorporates the use of an interceptor drain, shall indicate the effective depth of seasonal water table reduction.

3.1.2 Low hydraulic conductivity shall include soils with 40% or greater clay. Clay percentage shall be determined from in depth zone extending 6″ above and 12″ below installed drip tubing depth.

3.1.3 No loading rates are available for low hydraulic conductivity soils with greater than 60% clay.

3.1.4 Systems utilizing drip dispersal must maintain minimum of 9″ separation between drip tubing and any rock substrata (consolidated or fractured) for soils that exhibit a moderate and/or long SWT.

3.1.5 Systems utilizing drip dispersal must maintain minimum of 15″ separation between drip tubing and any rock substrata (consolidated or fractured) for soils that exhibit only a brief SWT or do not exhibit a SWT.

3.1.6 Soils that are structure less or with massive structure shall not be approved for onsite sub-surface treatment.

3.1.7 The lot size shall be of sufficient area to accommodate both the primary and secondary dispersal area. Both the primary and secondary dispersal area shall be sized according to the respective loading rates. If the lot can only support the primary dispersal field, a subsurface drip dispersal system shall not be installed.