Adjacent lots. As set forth in MGL c. 40A, § 6, adjacent lots under common ownership shall not be treated as a single lot for local zoning purposes if, at the time of recording or endorsement, the lots: i) conformed to then existing requirements of area, frontage, width, yard or depth, where each such lot has not less than 10,000 square feet of area and 75 feet of frontage; and ii) are located in a zoning district that allows for single-family residential use. Any single-family residential structure constructed on said lot shall not exceed 1,850 square feet of heated living area, shall contain not less than three bedrooms and shall not be used as a seasonal home or short-term rental.