South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-56 - ONSITE WASTEWATER SYSTEMS › Section 61-56.500 - Long-Term Acceptance Rate Standard for Onsite Wastewater Systems

Current through Register Vol. 48, No. 6, June 28, 2024
USDA-NRCS SOIL TEXTURE
SOIL CHARACTERISTICS WHEN MOIST (FIELD
							 TEST)
LONG-TERM ACCEPTANCE RATE
							 (GPD/SF)
Sand (S)
Sand has a gritty feel, does not stain the fingers,
							 and does not form ribbon or ball when wet or moist.
0.9 - 1.0
Class I
Loamy Sand (LS)
Loamy sand has a gritty feel, stains the fingers,
							 forms a weak ball, and cannot be handled without breaking.
Sandy Loam (SL)
Sandy loam has a gritty feel and forms a ball that
							 can be picked up with the fingers and handled with care without
							 breaking.
0.7 - 0.8
Class II
Loam (L)
Loam may have a slightly gritty feel but does not
							 show a fingerprint, and forms only short ribbons from 0.25 - 0.50 inch. Loam
							 will form a ball that can be handled without breaking.
Sandy Clay Loam (SCL)
Sandy clay loam has a gritty feel but contains enough
							 clay to form a firm ball and may ribbon from 0.75 - 1.0 inch.
0.5 - 0.6
Class III
Clay Loam (CL)
Clay loam is sticky when moist, forms a ribbon of 1.0
							 - 2.0 inches, and produces a slight sheen when rubbed with the thumbnail. Clay
							 loam produces a nondistinct fingerprint.
Silt Loam (SiL)
Silt loam has a floury feel when moist and will show
							 a fingerprint, but will not ribbon and forms only a weak ball.
Silt (Si)
Silt has a floury feel when moist and is sticky when
							 wet but will not ribbon and forms a ball that will tolerate some
							 handling.
0.1 - 0.4
Class IV
Silty Clay Loam (SiCL)
Silty clay loam has a slight floury feel, is sticky
							 when moist, and will ribbon from 1.0 - 2.0 inches. Rubbing with thumbnail
							 produces a moderate sheen. Silty clay loam produces a distinct
							 fingerprint.
Sandy Clay (SC)
Sandy clay is plastic, gritty, and sticky when moist,
							 forms a firm ball, and produces a ribbon in excess of 2.0 inches.
Clay ( C )
Clay is both sticky and plastic when moist, produces
							 a ribbon in excess of 2.0 inches, produces a high sheen when rubbed with the
							 thumbnail, and forms a strong ball resistant to breaking.
Silty Clay (SiC)
Silty clay has a slight floury feel, is both sticky
							 and plastic when moist, forms a ball, and produces a ribbon in excess of 2.0
							 inches.
(1) 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.
			 Alternative and experimental systems installed beneath expansive soils shall be
			 sized at a long-term acceptance rate not to exceed 0.2-0.25 gpd/sf as specified
			 in approved standards.
(2) Soil
			 texture shall be estimated by field testing as described above. Laboratory
			 determination of soil texture may be substituted for field testing when
			 conducted in accordance with: (1) Bouyoucos, G.J. 1962. Hydrometer Method
			 Improved for Making Particle Size Analyses of Soils. Agron. J. 53:464-465; (2)
			 ASTM D-422, Procedures for Sieve and Hydrometer Analyses; or (3) the Pipette
			 Method (ASA-CSSA-SSSA), USDA Methods of Soils Analysis, Soil Survey Laboratory
			 Information Manual, and Soil Survey Laboratory Methods Manual.
(3) The total linear feet (lf) for
			 conventional onsite wastewater systems shall be calculated by dividing the peak
			 daily flow (gpd) by the long-term acceptance rate (gpd/sf) and dividing the
			 result by the trench width (ft): lf = gpd ÷ gpd/sf ÷ ft. The total linear feet
			 for alternative systems may either be increased or decreased in accordance with
			 factors specified in alternative standards.