Run the house sewer in a straight line and avoid bends whenever
possible. Slight changes in direction may be made with one-sixteenth or
one-eighth bend fittings. For sharper changes of direction a manhole or
distribution box may be used. Changes in direction of more than 45 are
not recommended unless a manhole is provided. Clean-outs are desirable
within 5 feet of the septic tank where tanks are placed more than 20
feet from the building and the sewer line is not buried deeper than 4
feet.