Alteration, Reconstruction (which shall include raze and replacement), Extension or Structural Change (collectively "alteration") to Nonconforming Single- or Two-Family Residential Structures. Nonconforming single- or two-family residential structures may be altered, reconstructed, extended or structurally changed provided that such alteration does not increase the nonconforming nature of such structure.

Alteration, Reconstruction, Extension or Structural Change (collectively "alteration") to Nonconforming Structures Other than Single- and Two-Family Structures. Other nonconforming structures may be altered, reconstructed, extended or structurally changed on Special Permit from the Zoning Board of Appeals if the Zoning Board of Appeals finds that such alteration will not be substantially more detrimental to the neighborhood than the existing nonconforming structure or use. The alteration of a nonconforming structure in such manner as to create a new dimensional nonconformity or to intensify an existing dimensional nonconformity, shall require the Special Permit finding and the issuance of a variance by the Zoning Board of Appeals.

Restoration. A nonconforming structure or use may be reconstructed or reinstituted if destroyed by fire or other casualty if reconstructed or reinstituted within a period of 2 years from the date of the catastrophe, or else such reconstruction must comply with this chapter.

Abandonment. A nonconforming use or structure which has been abandoned or otherwise discontinued for a period of 2 years shall not be reestablished, and any future use of the premises shall conform to this chapter.

Reversion. Once changed to be conforming, no structure or use shall be permitted to revert to a nonconforming structure or use.

Exempted lots. A lot or parcel of land in a Residential District having an area, frontage, width or depth less than that required by this section may be developed for single residential use, provided that such lot or parcel complies with the specific exemptions of MGL c. 40A, § 6.

One single-family dwelling may be erected on any lot, regardless of a common ownership with that of adjoining land located in the same Residential District, which, at the time this subsection was adopted, March 9, 1971, contained at least 15,000 square feet and had a minimum frontage of 100 feet or has 50 feet of frontage on a cul-de-sac and the proposed structure is to be located on such lot so as to conform to the minimum requirements for such structures in effect at the time of the building.

One single-family dwelling may be erected, enlarged, or maintained on any lot, regardless of a common ownership with that of adjoining land located in the same residential district, which existed on August 2, 1973 or which was shown on a preliminary plan prior to that date and which was further shown on a definitive plan which was subsequently filed and approved by the Planning Board, and contained at least 20,000 square feet and had a minimum frontage of 120 feet or has 50 feet of arc frontage on a cul-de-sac and is 120 feet wide at the building line and the existing structure(s) or the proposed structure is located on such lot so as to conform with the minimum requirements of front, side and rear yard setbacks and to all other requirements for such structures in effect at the time of building.

Such nonconforming lots exempted under Subsections A, B, and C may be increased in size or shape or their land area recombined without losing this exemption, so long as the change does not increase the actual or potential number of lots.

One single-family dwelling may be erected on any lot, regardless of a common ownership with that of adjoining land located in the same Residential District, which, at the time this subsection was adopted, May 6, 1982, contained at least 40,000 square feet and had a minimum frontage of 150 square feet or 50 feet of arc frontage on a dead-end turnaround and is 120 feet wide at the building line or was an approved panhandle lot under § 164-5.3H and contained at least 20,000 square feet of buildable upland and the proposed structure is to be located on such lot so as to conform to minimum requirements for such structures in effect at the time of the building.

One single-family dwelling may be erected on any lot in a Residential District which, at the time this subsection was adopted, May 7, 1984, contained at least 40,000 square feet, of which a minimum of 30,000 square feet shall be of contiguous upland, as set forth in § 164-5.1, General requirements.

Commercial Lots. A lot or parcel of land in the Industrial District which existed at the time this amendment was adopted may be developed for commercial use provided the structure is located on the lot so as to conform with the minimum setbacks in effect at the time of construction.

One single-family dwelling may be erected on any lot pre-existing the passage of § 164-5.3H which had less than the required frontage and was shown on an approved subdivision plan.

Isolated lots and subdivisions. Under MGL c. 40A, § 6, lots not held in common ownership with any adjoining land are generally not subject to subsequent amendments in dimensional requirements, and land shown on subdivisions or other plans endorsed by the Planning Board is exempted from subsequent zoning amendments in certain respects for a limited period of time. (See MGL c. 40A, § 6.) Those exemptions are extended to other lots for single-family dwellings as specified in § 164-6.2B.

Up to 2 dwellings may be erected on any lot located in the General Business, Limited Business, or Village Center District, which lot is connected to public sewer services, regardless of common ownership with that of adjoining land located in the same district, and further provided that such lot existed on January 1, 2023.