Lot area, gross. The minimum lot size shall be 5,000 square feet for a single use and 10,000 square feet for mixed-use developments, with a minimum of 2,500 square feet for each use within a mixed-use development; or it shall be determined by the area of land necessary to meet the requirements of this chapter with respect to setbacks, maximum coverage, parking, circulation, landscaping, and other applicable county and state laws or regulations (such as those pertaining to wells and septic systems), whichever is greater.