Section 410IAC6-10.1-81. Table for on-site sewage system selection

   On-site sewage system selection may be summarized in Table VII as follows:

Table VII - Table for On-Site Sewage System Selection Based on Requirements of 410 IAC 6-10.1
Site Requirements	Subsurface Trench On-Site Sewage Systems					Elevated Sand Mound On-Site Sewage Systems (Sec. 80)
	Gravity Flow1 (Sec. 78, 79)		Flood Dosing or Alt. Fields1 (Sec. 78, 79)	Flood Dosing1 (Sec. 78, 79)	Pressure Dist. (Sec. 78, 79)
Slope	≤ 15%		≤ 15%	≤15%	≤15%	≤ 6%
Design Daily Flow	≥ 450	< 450	Any	Any	Any	Any
Acceptable Loading Rate Range for Determining System Size	≥ 0.25	≥ 0.25	≥ 0.25	≥ 0.25	≥ 0.25	≥ 0.25
	≤ 0.75	≤ 0.75	≤ 0.75	≤ 0.75	≤ 1.20	≤ 1.20
Distance from Trench Bottom (Ground Surface for Mounds) to Layer with a Soil Loading Rate < 0.25 gpd/ft2	≥ 30	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Distance from Trench Bottom (Ground Surface for Mounds) to Layer with a Soil Loading Rate > 1.20 gpd/ft2	≥ 24	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Distance from Trench Bottom (Ground Surface for Mounds) to Layer with a Soil Loading Rate = 1.20 gpd/ft2	≥ 24	≥ 24	≥ 24	≥ 24	Press. Dist. required for SLR = 1.20	≥ 0
Distance from Trench Bottom (Ground Surface for Mounds) to a Soil Horizon Developed from Wisconsin Glacial Till That Shows Effervescence3	≥ 30	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Distance from Trench Bottom (Ground Surface for Mounds) to Soil Horizon with < 20% Clay and > 35% Coarse Fragments by Volume	≥ 30	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Distance from Trench Bottom (Ground Surface for Mounds) to Soil Horizon with > 20% Clay and > 60% Coarse Fragments by Volume	≥ 30	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Distance from Trench Bottom (Ground Surface for Mounds) to Seasonal High Water Table2	≥ 24	≥ 24	≥ 24	≥ 24	≥ 24	≥ 20
Total Lineal Feet of Trench	≤ 500	≤ 500	≤ 500 for Alt. Fields	Any	Any	N/A
1These conditions are also suitable for subsurface trench pressure distribution on-site sewage systems.
2For subsurface trench systems, if the distance from trench bottom to seasonal high water table is less than twenty-four (24) inches, drainage must be installed in accordance with section 63 of this rule. For elevated sand mound systems, if the depth of the seasonal high water table is less than twenty (20) inches below the ground surface, drainage must be installed in accordance with section 59 of this rule.
3See Sections 62(a)(2)(E), 78(b)(6), 79(b)(3)(B), 79(c)(3)(B), 79(d)(2)(B) and 80(b)(5).
This chart does not include considerations such as the specific landscape features that must be met, the size of the soil absorption system, the size of the area necessary for construction of the soil absorption system on the contour with necessary setback and separation distances, dispersal area, the diversion of surface drainage, the feasibility of subsurface drainage, the ability to obtain easements, etc.
This chart does not take into consideration the necessity to pump the effluent to overcome differences in elevation (when a subsurface trench gravity system might otherwise be constructed).

(Indiana State Department of Health; 410 IAC 6-10.1-81; filed Oct 19, 2012, 2:07 p.m.: 20121114-IR-410120157FRA; errata filed Dec 12, 2012, 2:16 p.m.: 20121226-IR-410120157ACA)