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 A - Loading Rates in Square Feet Per Bedroom and Gallons/Square Feet/Day
|
Design Group |
Soil Group (Most Limiting Layer) |
Minimum Separation To Limiting Layer1 |
Permeability Range |
Size of System |
|
|
Residential Reg. Absorption (ft2/bedroom) |
Institutional/Commercial Allowable Application Rate (GPD/ft2) |
||||
|
I |
1A |
NR3 |
Very Rapid |
NR3 |
NR3 |
|
II |
2A; 2B; 2K |
3 feet |
Rapid |
200 |
1.0 |
|
III |
3B; 3K |
3 feet |
High Moderately Rapid |
220 |
0.91 |
|
IV |
3A; 3L; 4D; 4K |
3 feet |
Low Moderately Rapid |
240 |
0.84 |
|
V |
4A;; 4B; 4H; 4L; 5D |
3 feet |
Very High Moderate |
265 |
0.75 |
|
VI |
4F; 4M; 5B |
3 feet |
High Moderate |
290 |
0.69 |
|
VII |
4N; 5A; 5C; 5H; 5K; 6D |
2 feet |
Moderate |
325 |
0.62 |
|
VIII |
4O; 5E; 5I; 5L; 6A; 6B; 6E; 6H; 6K |
2 feet |
Low Moderate |
385 |
0.52 |
|
IX2 |
5F; 5M; 6C; 6L; 7D; 7F |
2 feet |
High Moderately Slow |
445 |
0.45 |
|
X2 |
5G; 6F; 6I; 7E; 7C; 7H |
2 feet |
Low Moderately Slow |
500 |
0.40 |
|
XI2 |
5N; 6G; 6J; 6M; 7F; 7I |
2 feet |
Slow |
740 |
0.27 |
|
XII2 |
7G; 7J; 7L; 8E; 8I |
2 feet |
Very Slow |
1000 |
0.20 |
|
XII2 |
5O; 6N; 6O; 7M; 7N; 7O; 8J; 8M; 8O |
NR3 |
NR3 |
NR3 |
0.00 |
|
XIII |
9 |
SUBSURFACE DISPOSAL NOT RECOMMENDED |
|||
NOTES:
1 Limiting layers include fragipans; bedrock; compact glacial tills; seasonal high water table or other soil profile features that will materially affect the absorption of liquid from the disposal field.
2 Soils in this group are less than the minimum percolation rate established in Appendix A, Illustration H as suitable for subsurface seepage systems.
3 NR = Subsurface disposal system not recommended.
