Figure: 30 TAC §285.91(5)
Table V. Criteria for Standard Subsurface Absorption Systems.
FACTORS |
SUITABLE (S) |
UNSUITABLE (U) |
Topography |
Slopes 0-30% | Slopes
greater than 30% Complex slopes |
Subsoil Texture |
Soil
Class Ib, II, or III soils along the sidewall and two feet below the bottom of the
excavation |
Soil Class Ia soils along the sidewall or within two feet below
the bottom of the excavation (Except for lined ET) Soil Class IV along the sidewall or within two feet below the bottom of the excavation (Except for pumped effluent and ET) |
Restrictive Horizon |
No restrictive horizon intersects the sidewall or is within 24 inches below the bottom of the proposed excavation. | A restrictive horizon intersects the sidewall or is within 24 inches below the bottom of the proposed excavation (Except as indicated in §285.33(b)(1)(A)(vi)) |
Gravel analysis |
In
Class II or III soils, only; Gravel portion less than 30% and gravel greater than 2.0 mm; or If greater than 30% gravel, 80% of the gravel portion must be less than 5.0 mm |
All
other Class II and III soils, which contain gravel in excess of what is described as
suitable All other soils with greater than 30% gravel |
Groundwater |
No indication of seasonal groundwater anywhere within 24 inches of the bottom of the proposed excavation. | Indications of seasonal groundwater or drainage mottles anywhere within 24 inches of the bottom of the proposed excavation (Except for lined ET) |
Flood Hazard |
No flooding potential. | Areas
located in the floodplain and regulatory floodway unless system designed according to
§285.31(c)(2) Depressional areas without adequate drainage |
Other |
Fill material |