Septic tank absorption fields are areas in which effluent from a septic tank is

distributed into the soil through subsurface tiles or perforated pipe. Only that

part of the soil between depths of 24 and 60 inches is evaluated. The ratings

are based on the soil properties that affect absorption of the effluent,

construction and maintenance of the system, and public health. Saturated

hydraulic conductivity (Ksat), depth to a water table, ponding, depth to

bedrock or a cemented pan, and flooding affect absorption of the effluent.

Stones and boulders, ice, and bedrock or a cemented pan interfere with

installation. Subsidence interferes with installation and maintenance.

Excessive slope may cause lateral seepage and surfacing of the effluent in

downslope areas.