System types 1 and 2, and drip distribution systems shall use the most limiting soil loading rate 18 inches below the wastewater application point to size the soil absorption component. System Types 3, 4 & 5, and the Illinois Raised Filter Bed, shall use the most limiting soil loading rate in the upper 12 inches of soil to size the soil absorption component.
Till/ Lacustrine | Outwash |
Till/ Lacustrine | Outwash | |
Gravelly coarse sand | 0.00 | 0.00 |
Moderate or strong platy structure | 0.00 | 0.00 |
Sandy clay loam, silty clay loam, or finer, and weak platy structure | 0.00 | 0.00 |
Moist soil consistence stronger than firm or any cemented class | 0.00 | 0.00 |
Sandy clay, clay, or silty clay texture and weak or massive structure | 0.00 | 0.00 |
Sandy clay loam, clay loam, silty clay loam, silt, loam or silt loam texture and massive structure | 0.00 | 0.00 |
Sandy clay, clay, or silty clay texture of low clay content and moderate or strong structure | 0.20 | 0.20 |
Sandy clay loam, clay loam, silty clay loam or silt loam texture with weak structure | 0.20 | 0.30 |
Clay loam, silty clay loam, or silt loam texture and moderate or strong structure | 0.40 | 0.50 |
Sandy loam or loam texture and weak structure | 0.40 | 0.50 |
Sandy clay loam, sandy loam, or loam texture and moderate or strong structure | 0.50 | 0.70 |
Fine sand, very fine sand, loamy fine sand, or loamy very fine sand | 0.60 | 0.70 |
Loamy sand, sand, or coarse sand texture | 0.80 | 0.80 |
Whenever a NSF ANSI Standard Number 40 pretreatment unit is proposed, the wastewater loading rate may be increased
by a factor of 20% as follows:
0.20 —> 0.24
0.30 —> 0.36
0.40 —> 0.48
0.50 —> 0.60
0.60 —> 0.72
0.70 —> 0.84
0.80 —> 0.96
Whenever an NSF ANSI Standard Number 350 pretreatment unit is proposed, the wastewater loading rate may be increased by a factor of 100% as follows:
0.20 —> 0.40
0.30 —> 0.60
0.40 —> 0.80
0.50 —> 1.0
0.60 —> 1.2
0.70 —> 1.4
0.80 —> 1.6