A. Supply pipes must be designed, installed and protected so that effluent will not freeze in the pipe;

B. Supply pipes 5 feet entering and 5 feet exiting the septic tank shall meet the strength requirements of American Society for Testing and Materials (ASTM) Schedule 40 plastic pipe. Distribution pipes must meet the SDR 34 or equal rating. All pipes must be supported in a manner so that there is no deflection or longitudinal bending during the backfilling and subsequent settling of the soil; and

C. Serial distribution must be used to distribute effluent to individual trenches in an absorption system. If the necessary elevation differences between trenches for serial distribution cannot be achieved by natural topography or by varying the excavation depths, parallel distribution may be used. Serial distribution shall not create a pressure head on trenches at lower elevations.