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