All lots must provide a contiguous minimum developable land area within the lot. The contiguous developable land area within the lot shall be equal to or greater than the applicable minimum lot area required for the zone district in which the lot is located. The contiguous developable land area must also meet the minimum lot dimensions required by the zone district, except that the minimum contiguous developable land area is not required to exceed 40,000 square feet where the lot is served by public sewer and public water, nor is it required to have a minimum dimension greater than 150 feet. Where the lot is not served by public sewer or by public water, the contiguous developable land area within the lot is not required to exceed 80,000 square feet nor is it required to have a minimum dimension greater than 150 feet.