Ill. Admin. Code tit. 77, pt. 905, app A, ILLUSTRATION H, exh. B
Current through Register Vol. 48, No. 45, November 8, 2024
Time (minutes) required for last 6 inches of water to fall | FOR RESIDENTIAL USE Required Absorption Area (sq ft)/bedroom) | FOR INSTITUTIONAL OR COMMERCIAL USE Allowable application rate (GPD/sq ft) (5) | Recommended depth from bottom of the trench to the limiting layer | |||
8 inch | 10 inch | 8 inch | 10 inch | |||
18 - 60 | 100 | 70 | 2.00 | 3.00 | ||
90 | 105 | 70 | 1.90 | 2.86 | 3 feet | |
120 | 120 | 80 | 1.66 | 2.50 | ||
150 | 135 | 90 | 1.48 | 2.22 | ||
180 | 145 | 100 | 1.38 | 2.00 | ||
240 | 160 | 110 | 1.25 | 1.82 | ||
300 | 175 | 120 | 1.14 | 1.66 | 2 feet | |
360 | 195 | 130 | 1.0 | 1.54 | ||
NOTE: | ||||||
1. | Over 360 is unsuitable for subsurface seepage systems. | |||||
2. | Under 18 is unsuitable for subsurface seepage systems. | |||||
3. | Divide the required total gallons per day by this number to get the number of lineal feet required. | |||||
Ill. Admin. Code tit. 77, pt. 905, app A, ILLUSTRATION H, exh. B