Illinois Administrative Code › Title 77 - PUBLIC HEALTH › Part 905 - PRIVATE SEWAGE DISPOSAL CODE › Appendix A - Illustrations and Exhibits › ILLUSTRATION M - Soil Suitability for On-Site Sewage Design › Exhibit B - Key for Determining Sewage Loading Rates (Gallons/Square Foot/Day)

Current through Register Vol. 48, No. 28, July 12, 2024
Structure and Parent Material
Single grain; Weak ;
								Platy2
Granular, Angular and Subangular
								Blocky; Prismatic
Structureless or Massive
Loess: Outwash; Alluvium;
								Lacustrine8
Till3
Week
Moderate; Strong
Strong
Moderate; Strong
Loess; Outwash; Alluvium;
								Lacustrine8
Till3
Moist Consistence
lo vfr fr
vfr fr
fi
vfr
fi
vfr fr
fi
fr
fi
vfi
vfr
fr
fi
vfr fr
fi vfi
Texture
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
1. Fragmental; Ext. or Very gravelly sand
> 1.004
N/A5
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2. Sand; Loamy course sand; Loamy sand; Gravelly
								sand; Coarse sand; Gravelly loamy sand
1.00
1.00
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
1.00
N/A
N/A
N/A
N/A
3. Fine sand; Loamy fine sand; Coarse sandy
								loam
0.84
0.91
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
0.91
0.84
N/A
N/A
N/A
4. Sandy loam; Fine sandy loam; Gravelly sandy
								loam; Gravelly loam; Gravelly silt loam
0.75
0.75
N.A
0.84
N/A
0.69
N/A
N/A
0.75
N/A
0.84
0.75
0.69
0.62
0.52
5. Loam; Silt loam; Very fine sandy loam; Sandy
								clay loam; Silt; Very fine sand; Loamy very fine sand; Gravelly clay
								loam
0.62
0.69
0.62
0.75
0.52
0.456
0.406
0.62
0.52
N/A
0.62
0.52
0.456
0.276
N/R7
6. Silty clay loam (<35% c); Clay loam (< 35%
								c)
.052
0.52
0.456
0.62
0.52
0.408
0.276
0.52
0.406
0.276
0.52
0.456
0.276
N/R
N/R
7. Silty clay loam (>35% c); Clay loam (>35%
								c)
N/A
N/A
0.406
0.456
0.406
0.276
0.206
0.406
0.276
0.206
N/A
0.206
N/R
N/R
N/R
8. Sandy clay; Clay
N/A
N/A
N/A
N/A
0.206,9
N/A
N/A
N/A
0.206,9
N/R
N/A
N/A
N/R
N/A
N/R
9. Organics; Fragic; Lithic; Paralithic
---SOIL PROPERTIES HAVE VERY SEVERE LIMITATIONS;
								SUBSURFACE DISPOSAL NOT RECOMMENDED-----
FOOTNOTES:
1 Disturbed soils are highly
					 variable and require special on-site investigations.
2 Moderate or strong platy
					 structure for the soil textures in Groups 4, 5 and 6 have a loading rate of
					 0.40 g/sq.ft/d. Platy structure having firm or very firm consistency or caused
					 by mechanical compaction has a loading rate of 0.0 g/sq.ft/d.
3 Basal glacial tills structured
					 by geogenic processes have the same loading rates as structureless glacial
					 till.
4 This soil group is estimated
					 to have very rapid permeability and exceeds the maximum established rate in
					 Illustration H, Exhibit A.
5 N/A means not
					 applicable.
6 These soil groups are
					 estimated to have moderately slow to very slow permeability and are less than
					 the minimum established rate in Illustration H, Exhibit A.
7 N/R means not recommended.
					 These soils have loading rates considered too low for conventional subsurface
					 disposal.
8 In some areas, lacustrine
					 material may have physical properties similar to glacial till and should be
					 placed in the glacial till columns.
9 Non-swelling (1:1 lattice)
					 clays formed in bedrock residuum have a loading rate of 0.27 g/sq.ft/d.
					 Swelling (2:1 lattice) clays are not recommended for subsurface
					 disposal.