South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-56 - ONSITE WASTEWATER SYSTEMS › Section 61-56.400 - Appendices of Standards for Permitted Systems › Appendix 61-56.400.A - System Standard 100/101 - Conventional with 14-Inch Aggregate Depth

Current through Register Vol. 48, No. 6, June 28, 2024
(1) Site/Permitting Requirements
(a) The depth to the zone of saturation (ZOS) must be at
				  least twenty-nine (29) inches below the naturally occurring soil surface and at
				  least six (6) inches below the bottom of the proposed wastewater infiltration
				  trenches at the deepest point of effluent application.
(b) The depth to any restrictive horizon must be greater than
				  twelve (12) inches below the bottom of the proposed wastewater infiltration
				  trenches at the deepest point of effluent application.
(c) The long-term acceptance rate for system sizing shall be
				  based upon the most hydraulically limiting naturally occurring soil texture
				  from the ground surface to twelve (12) inches below the bottom of the proposed
				  wastewater infiltration trenches.
(d) There shall be a replacement area equivalent to at least
				  fifty (50) percent in size of the original system area held in reserve for
				  system repair. This area shall have a suitable configuration and shall meet the
				  minimum soil and site conditions of this regulation.
(e) This system must not be used on sloping sites that
				  require serial distribution unless it can be demonstrated that the entire
				  wastewater infiltration trench installation (i.e., side wall to side wall and
				  end to end) can meet the required textural limitations and the required offsets
				  to the zone of saturation and restrictive horizons.
(2) Installation Requirements
(a) The wastewater infiltration trench aggregate shall be
				  fourteen (14) inches in depth and shall be placed so as to provide seven (7)
				  inches of aggregate below the pipe, four (4) inches beside the pipe, and three
				  (3) inches above the pipe. The aggregate shall be covered with at least nine
				  (9) inches of soil.
(b) The wastewater infiltration trench width shall be
				  thirty-six (36) inches.
(c) Where gravity flow from the septic tank to the subsurface
				  wastewater infiltration area is utilized, the invert elevation of the septic
				  tank outlet shall be installed at an elevation at least equal to or higher than
				  the top of the aggregate in the highest wastewater infiltration
				  trench(es).
(d) All tree and brush removal shall be done in a manner that
				  minimizes the disturbance or loss of naturally occurring soil.
(3) Final Landscaping and Drainage
(a) Installation of drainage swales, ditches, curtain drains,
				  and rain gutters may be required to divert or intercept water away from the
				  onsite wastewater system location to a positive outfall. The septic tank and
				  subsurface wastewater infiltration area shall be backfilled and shaped to
				  promote surface water runoff.
(b) A barrier to preclude parking and vehicular traffic over
				  the system area may be required.
(c) Following final landscaping, seeding, or sodding may be
				  required to prevent erosion.
(d) Final approval shall be withheld until all landscaping
				  and drainage improvements have been satisfactorily completed.
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