A. The lot sizes be larger than the minimum district lot sizes, in order to protect the public health;

B. Due to the sensitivity of the aquifer recharge areas locally, a form of secondary treatment may be required in the aquifer recharge areas or areas where the ground water table is a concern;

C. When an existing onsite wastewater system has been previously installed in a 100-year floodplain, then the new or repaired system shall meet or exceed the requirements of this manual and all local ordinances. The system as approved by the Director shall be designed to minimize or eliminate infiltration of floodwaters into the system, and discharge of the system into the floodwaters;

D. A registered professional engineer or soil scientist shall perform the percolation tests or other soil evaluations, due to the lot being located in one of the areas classified as a sensitive regional area;

E. The onsite wastewater system shall be designed by a registered professional engineer;

F. The septic tank will be required to be a multi-compartmental or multiple tanks with a combined minimum capacity of 1,500 gallons;

G. Horizontal separation distances from onsite wastewater systems and other pertinent ground features shall be 1.5 times the minimum distances required in § 13.20.170;

H. All new, repaired or upgraded onsite wastewater systems within a sensitive regional area will be required to meet, at minimum, the requirements listed in § 13.20.300 for calculating the design flow;

I. Drainfields in the sensitive regional areas, whether absorption trench systems or beds are used, may not be allowed to receive credit reductions when they are being sized unless certified by a registered professional engineer;

J. Onsite wastewater systems shall not be permitted in highly permeable soils (percolation rate faster than 5 minutes per inch), except where the site evaluation has demonstrated that surface and ground water quality will be protected;

K. Existing systems may be required to be retrofitted with an effluent filter;

L. Existing onsite wastewater systems, which conform to this Chapter, ARSD Chapter 74:53:01, and all applicable local ordinances, shall be permitted to remain as installed, unless the onsite wastewater system is found to be in noncompliance.