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.P - System Standard 601 - Elevated Infiltration System

Current through Register Vol. 48, No. 6, June 28, 2024
(1) Site/Permitting Requirements
(a) The texture in the upper eighteen (18) inches of
				  naturally occurring soil must be Class I or Class II.
(b) The filter shall not be placed on slopes greater than
				  three (3) percent.
(c) This system cannot be considered for facilities with peak
				  flow rates in excess of four hundred eighty (480) gpd. This system shall not be
				  considered for facilities requiring grease traps.
(d) There shall be a buffer of at least fifty (50) feet
				  surrounding and separating the system from all adjacent property lines. This
				  buffer shall be measured from the retaining wall.
(e) 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.
(f) No part of this system can be installed within one
				  hundred twenty-five (125) feet of the critical area line or tidal waters as
				  determined by the Department or within one hundred twenty-five (125) feet of
				  the ordinary high water elevation within the banks of non-tidal,
				  environmentally sensitive waters.
(g) The total bottom area of the filter must be increased by
				  fifty (50) percent above that required for conventional trenches.
(h) This system may be considered for installation on
				  contiguous lots in new subdivisions approved after the effective date of this
				  standard provided a setback of at least seventy-five (75) feet is maintained
				  between the system and all adjacent property lines. The seventy-five (75) foot
				  setback shall be measured from the point at which the retaining wall intersects
				  the naturally occurring soil surface.
(2) Installation Requirements
(a) Site Preparation
(i) If present within eighteen (18) inches of the naturally
				  occurring soil surface, organic material and restrictive horizons must be
				  removed from beneath the filter and replaced with USDA medium sand, washed
				  concrete sand, or an equivalent material approved by the Department.
(ii) The naturally occurring soil surface underlying the
				  filter shall be thoroughly tilled and mixed with the imported filter material
				  to a depth of six (6) inches.
(b) System Requirements
(i) The filter must be constructed to a height of at least
				  thirty-six (36) inches above the original grade with the sewage effluent
				  passing through at least twenty-four (24) inches of filter material.
(ii) The filter material shall be USDA medium sand, washed
				  concrete sand, or other material approved by the Department.
(iii) The filter retaining wall shall extend at least four
				  (4) inches above the surface of the filter material and shall penetrate the
				  naturally occurring soil surface at least four (4) inches.
(iv) The filter retaining wall shall be constructed in
				  accordance with the accompanying design illustrations.
(v) Effluent discharged to this system must receive a higher
				  degree of treatment than that provided by a conventional septic tank (e.g., two
				  (2) compartment septic tank or two (2) septic tanks in series).
(vi) The top of the filter shall be capped with Class II or
				  Class III soil and shall slope from center to edges in order to promote surface
				  runoff.
(c) Distribution Requirements
(i) Low Pressure Pipe Distribution (LPP) must be utilized to
				  preclude localized hydraulic overloading of the imported fill material and to
				  minimize the impact on the shallow zone of saturation.
(ii) Low Pressure Pipe Distribution (LPP) must be designed
				  and installed in accordance with Department standards or equivalent designs.
				  The size and layout of each distribution system will vary based on the size of
				  the filter and the needed dosing.
(iii) Pump design shall be in accordance with Department
				  standards.
(3) Final Landscaping and Drainage
(a) Fill material shall be placed around the outside of the
				  filter to a depth of one (1) foot, and shall slope to original grade at a point
				  five (5) feet from the retaining wall.
(b) The septic tank and filter area shall be backfilled and
				  shaped to promote the runoff of surface water.
(c) Where natural surface drainage does not exist, a swale
				  shall be constructed adjacent to the filter to divert surface water away from
				  the onsite wastewater system to a positive outfall. The installation of
				  ditches, curtain drains, and/or rain gutters may be required to intercept and
				  divert water away from the onsite wastewater system location.
(d) Following final landscaping, seeding or sodding may be
				  required to prevent erosion.
(e) Final approval shall be withheld until all landscaping
				  and drainage improvements have been satisfactorily completed.
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