(A) General. Proposed soil based onsite wastewater treatment systems shall meet the design requirements specified in this section, as the requirements apply to the system type, and in accordance with the design requirements further specified in the incorporated materials of Appendix A for a system type not specified.
(B) Suitable soil. A soil treatment component and its required reserve soil treatment area shall be located in suitable soil in accordance with the requirements of § 171.087. The shallowest limiting layer depth of the soil borings that define the area proposed for the soil treatment component shall determine the system type.
(C) Minimum vertical separation distance. Proposed soil based onsite wastewater treatment systems shall be designed to use a system type most appropriate for a site’s soil characteristics in order to maintain a minimum vertical separation distance between the limiting layer and the wastewater application point.
(D) System type. Any soil treatment system and its required reserve soil treatment area shall be of an onsite wastewater treatment system type as specified by Table B.3 (Appendix B), and the design for that onsite wastewater treatment system type shall conform to the requirements of this section and any applicable elements of materials incorporated by Appendix A. An onsite wastewater treatment system may be comprised of two different types of systems.
(E) Site contour. Any primary soil treatment component and its required reserve soil treatment area shall be designed to be parallel to the site contour. Soil treatment systems shall not be situated on slopes that are concave to the extent that horizontal subsurface movement of wastewater may concentrate that flow in a small downslope area.
(1) Tolerance. The maximum variation off contour along the entire length of the soil treatment component shall be no more than 1%.
(2) Concave configuration. For Type 3, 4 and 5 systems, the maximum deflection of a concave soil treatment component shall be no more than 10%.
(F) Low pressure pipe distribution networks. Distribution of wastewater into onsite wastewater treatment systems by low pressure pipe (LPP), when part of an onsite wastewater treatment system designed in accordance with the requirements of this section, shall meet the following minimum requirements:
(1) Minimum supply/manifold line diameter shall be two inches.
(2) Minimum lateral wastewater distribution pipe diameter shall be one and one-half inches.
(3) Minimum perforation size shall be three-sixteenths inches.
(4) Maximum perforation spacing shall be six feet in Type 1 and 2 systems and three feet in Type 3, 4 and 5 systems.
(5) Minimum distal end pressure on any lateral line shall be one foot of pressure head (0.43 psi).
(6) Maximum distal end pressure on any lateral line shall be five feet of pressure head (2.16 psi).
(Ord. [Bd of Health Ord., Art. V], passed 11-12-1996; Ord. [Bd of Health Ord., Art. V], passed 11-12-2013)