13.20.490 Class II dwelling sizing factors.
The following criteria in Table 5b may be used for the design of individual or small onsite wastewater systems classified as Class II dwellings, if the absorption trench system is of an area sufficient for at least 3 bedrooms. The absorption area shall be determined according to the following:
Percolation Rate | Minimum Absorption Trench Area |
|---|---|
(Minutes for water to drop 1 inch) | (Square feet of trench bottom per bedroom) |
1 but less than 5 minutes per inch | Not permitted–see ARSD § 74:53:01:33 |
5 but less than 10 minutes per inch | 155 square feet |
10 but less than 15 minutes per inch | 200 square feet |
15 but less than 30 minutes per inch | 250 square feet |
30 but less than 45 minutes per inch | 300 square feet |
45 but less than 55 minutes per inch | 375 square feet |
55 but no more than 60 minutes per inch | 425 square feet |
Over 60 minutes per inch | Not permitted–see ARSD § 74:53:01:33 |