The acceptability of a lot or site to support an onsite wastewater system of the type and size, as required by this chapter and all applicable local ordinances, shall be determined on the basis of the approved soil test data, site conditions, and daily sewage flow quantity and characteristics. Site conditions include, but are not limited to, lot size, slope, restrictive soil layer elevation, rock outcroppings, bedrock elevation, seasonal ground water elevation, sinkholes, surface drainage, or flood-prone areas. The Director may conduct a site evaluation, prepare a report of findings, and prescribe the size and location of a conventional onsite wastewater system or repair of such system. When a site meeting the requirements of this chapter has been chosen for location of the proposed onsite wastewater system, the suitability of the soil for treatment and disposal of the effluent shall be determined as prescribed below. This determination shall be made based upon soil characteristics observed by percolation test results, soil observation pits, and/or soil borings, as well as any other related data that may be required by the Director.