This chapter as to the use of a lot for single family residential purposes shall not apply to any lot which prior to January 1, 1970, was specifically described as an identifiable and separate lot either in the instrument conveying such lot to the then owner or in a valid and enforceable agreement for purchase and sale or was shown on a plan recorded in accordance with law, prior to January 1, 1970; provided that contiguous lots in the same ownership on or after October 3, 1973 shall be considered as one lot for the purposes hereof.   [PL 1973, c. 651 (NEW).]

This chapter shall not apply to any structure in existence and in place on or before October 3, 1973, which then or theretofore disposed of wastes by means of subsurface waste disposal; except that no person shall reduce the size of the lot upon which such structure is located to a size or frontage less than that allowed by section 4807-A unless permitted pursuant to section 4807-B.   [PL 1973, c. 651 (AMD).]