South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-56 - ONSITE WASTEWATER SYSTEMS › Section 61-56.202 - Minimum Requirements for Onsite Wastewater System Final Treatment and Disposal Systems

Current through Register Vol. 48, No. 6, June 28, 2024
(1) All
			 pipe utilized in onsite wastewater systems shall meet applicable ASTM
			 standards. All piping utilized in the connection of a septic tank to a
			 subsurface wastewater infiltration area, including that which is utilized in
			 the connection of adjacent wastewater infiltration trenches, whether they be
			 level or serially fed, shall be non-perforated Schedule 40 PVC pipe. Such pipe,
			 excluding force mains, shall be a minimum of three (3) inches in diameter. The
			 connecting pipe shall not be surrounded by aggregate.
(2) At least seven (7) feet of undisturbed
			 earth shall exist between wastewater infiltration trenches.
(3) The aggregate used in onsite wastewater
			 systems shall be a material approved by the Department and shall range in size
			 from one-half (1/2) inch to two and one-half (2 1/2) inches. Fines shall be
			 prohibited. Tire chips shall range in size from one-half (1/2) inch to four (4)
			 inches in size, and wire strands shall not protrude more than one-half (1/2)
			 inch from the sides.
(4) Drop boxes
			 shall be utilized when deemed necessary by the Department. When required, they
			 shall be surrounded and stabilized by at least two (2) feet of undisturbed or
			 manually compacted earth, and the wastewater infiltration trenches shall be fed
			 with non-perforated Schedule 40 PVC pipe. The invert of the drop box overflow
			 pipe shall be at the same elevation as the top of the aggregate in the trenches
			 fed by that box, and the top of the aggregate shall be level throughout the
			 trench run. Other methods that affect serial distribution shall also overflow
			 at the same elevation as the top of the aggregate.
(5) There shall be at least two (2) feet of
			 earthen buffer between the septic tank and all portions of adjacent wastewater
			 infiltration trenches. Where gravity flow is utilized, the invert elevation of
			 the septic tank outlet shall be at the same elevation or higher than the top of
			 the aggregate in the highest placed wastewater infiltration trench.
(6) To ensure proper operation and protection
			 of onsite wastewater systems, the Department may require individual or combined
			 installation of drainage swales, curtain or interceptor drains, protective
			 barriers, or protective ground cover. Final approval of the permit may be
			 withheld until such time as these improvements are completed.
(7) The bottom of each wastewater
			 infiltration trench, including the distribution pipe contained within, shall be
			 as level as possible, with an elevation differential not to exceed two (2)
			 inches throughout the trench run.
(8) The required number, length, and
			 configuration of wastewater infiltration trenches shall be determined by the
			 Department and shall be based upon the Standard for Determining Peak Sewage
			 Flow Rates (Section
			 501, Peak Sewage Flow Rate Standard)
			 from Commercial and Recreational Establishments in conjunction with the
			 Long-Term Acceptance Rate Standard for Onsite Wastewater Systems (Section
			 500, Long-Term Acceptance Rate
			 Standard for Onsite Wastewater Systems). All systems shall be sized 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.
(9) The aggregate over the distribution pipe
			 shall be covered with a strong, untreated pervious material to prevent
			 infiltration of backfill material.