On lots less than three (3) acres, prior to adjustment for capping fill, where the slope is less than or equal to twelve percent (12%), all undisturbed soils exhibiting a depth of thirteen inches (13”) or greater to a brief seasonal water table, and/or a depth of eighteen inches (18”) or greater to an adjusted moderate seasonal water table, and/or a depth of twenty-four inches (24”) or greater to an adjusted long seasonal water table shall utilize a standard onsite wastewater system as outlined in this part.