Consult the septic system design and mark the area where the drain field will be located with flags.
Cut any trees in the drain field area flush with the ground level and mow grass to no more than two inches high.
Position the excavator next to the absorption area of the drain field. Use the teeth of the bucket to roughen the turf layers so the mound sand can come in contact with the soil.
Place clean sewer sand on top of the roughed up area into the shape and elevations as specified in the septic design.
Use a skid steer to cut a level area in the sewer sand underneath the future rock-bed area of the drain field.
Place sewer rock into the level portion of the sewer sand to the elevation specified in the septic design.
Hand-dig three trenches in the sewer rock evenly spaced to accommodate the drain field laterals. Place the laterals in the trenches so their perforations are pointing downward and their tops are covered with two inches of rock.
Unroll the geo-textile fabric on top of the rock bed.
Place sandy loamy soil over the entire area, including the sand and rock-bed with the tracked skid steer. Contour the loam until slopes with a 10:1 ratio are achieved with the tracked skid steer.
Place six inches of topsoil over the entire area and level. The completed drain field should slope at a ratio of no steeper than 3:1.