South Dakota Administrative Rules › Title 74 - Department of Environment And Natural Resources › Article 74:53 - Water supply and treatment systems › Chapter 74:53:01 - Individual and small on-site wastewater systems › Section 74:53:01:28 - Distribution of septic tank effluent to absorption fields

Current through Register Vol. 51, page 10, July 15, 2024
The pretreated effluent from a septic tank shall be distributed to the
	 absorption field using the following criteria:
(1) On relatively flat terrain where the
  elevation difference of the ground surface does not exceed 6 inches in any
  direction within the absorption field, the septic tank effluent may be directed
  to the absorption field through a system of interconnecting distribution
  pipes;
(2) On slightly sloping
  terrain where the elevation difference of the ground surface does not exceed 28
  inches in any direction within the absorption field, the septic tank effluent
  may be distributed by a distribution box provided the final ground surface
  elevation of the lowest trench is at least one foot higher than the invert
  elevation of the outlets of the distribution box. The inverts of all outlets
  shall be at the same elevation as measured from a liquid surface which is at
  least 4 inches above the distribution box floor. The inlet pipe invert shall be
  at least 1 inch higher than outlet inverts. Each absorption line shall be
  connected separately to the distribution box and shall not be subdivided. When
  the septic tank effluent is pumped to the distribution box, either a baffle
  wall shall be installed in the distribution box or the pump discharge shall be
  directed against a wall of the box on which there is no outlet. The baffle
  shall be secured to the box and shall extend at least 1 inch above the crown of
  the inlet pipe. The distribution box shall be watertight with a removable
  cover, constructed of durable materials resistant to corrosion or decay and
  shall have sufficient capacity to handle the maximum daily flow rate;
  and
(3) On sloping terrain where
  the elevation difference of the ground surface exceeds 28 inches in any
  direction within the absorption field, a serial distribution system shall be
  installed. The serial distribution system shall be connected with drop boxes or
  closed pipe relief lines in such a manner that each trench is completely filled
  with septic tank effluent to the full depth of the gravel before effluent flows
  to succeeding trenches. The drop boxes or relief lines shall be placed on an
  undisturbed section of ground. The first drop box or relief pipe arrangement
  encountered shall not have the crown of the outlet pipe at its highest point
  above the invert of the septic tank outlet. At each drop box or relief
  arrangement, the invert of the inlet pipe shall be between 1 and 2 inches
  higher than the invert of the outlet pipe to the succeeding trench. The slope
  of the trench between the invert of the outlet and the invert of the inlet of
  successive drop box or relief pipe arrangements shall be 1 inch per 100 feet.
  When septic effluent is delivered to the drop box by a pump, the pump discharge
  shall be directed against a baffle wall or against a wall of the box on which
  there is no outlet. The drop box shall be watertight with a removable cover,
  constructed of durable materials resistant to corrosion or decay, and shall
  have sufficient capacity to handle the maximum daily flow rate.
General Authority:
SDCL
		34A-2-93.
Law Implemented:
SDCL
		34A-2-20.