A use listed in Article V is permitted as of right in any district under which it is denoted by the letter "Y" subject to the applicable definitions in Article II.

A use listed in Article V is permitted as of right, with site plan review under § 9.03 in any district under which it is denoted by the letters "SR" subject to the applicable definitions in Article II.

A use listed in Article V is permitted as a special exception in any district under which it is denoted by the letters "SP" only if the PGA so determines and issues a special permit therefor as provided in Article IX subject to the applicable definitions in Article II and to such further restrictions as said PGA may establish. Uses denoted by the letters "SP/SR" require a special permit with site plan review under Article IX.

A use listed in Article V which is denoted by the letter "N" is not permitted, except nonconforming uses which may be continued under the provisions of § 4.05.

Permitted and required accessory uses shall be on the same lot of record as the principal use to which they are accessory and shall be such as not to alter the character of the premises on which it is located.

No accessory use or uses within a building other than an accessory garage shall occupy more than a combined total of 25% of the floor area of the principal building.

No residential accessory structure/building shall occupy part of the required Front Yard, but such building may occupy not more than 30% of any other minimum required yard setback or existing yard area, whichever is greater; in addition, no residential accessory building facade shall exceed 30 feet in length.

No part of a residential accessory building shall be located nearer than five feet to any side or rear lot line nor:

Commercial accessory parking structures shall comply with all other applicable sections of this code. In addition, commercial accessory parking structures may occupy more than 30% of any other minimum required yard setback or existing yard area, provided that no more than 30% of said yard area is occupied by the parts of said parking structure extending above the finished grade of the lot.

No accessory use shall be permitted in any district except insofar as it is accessory to a principal use permitted in the district.

Swimming pools having a water depth of two feet or more when full and ready for use shall be considered an accessory building for the purposes of interpreting this Zoning Ordinance. Swimming pools shall be screened by an opaque wall, barrier or uniform fence at least five feet high and capable of prohibiting unauthorized use. In addition, swimming pools constructed below grade must be equipped with a permanently installed drainage system. Swimming pools with their associated walkways, aprons, raised decks, and their associated equipment shall not be located in a Front yard and shall be setback at least five feet from any side or rear Lot Line, and subject to appropriate Screening as determined by the Board of Appeals. The above regulations shall not apply to those swimming pools that are portable in nature.

Accessory structures fronting on a public street or way shall be subject to the Front Yard Setback requirements of the district in which it is located.

Any trade, industry, or other use that is noxious, offensive, or hazardous by reason of vibration or noise or the emission of odors, dust, gas, fumes, smoke, cinders, flashing or excessively bright light, refuse matter, or of any other cause;

Any use hazardous to the health, safety, and general welfare because of danger of flooding, inadequacy of drainage or inaccessibility to firefighting apparatus or other protective services;

Any advertising sign or device, except as permitted under Article VII.

Except as hereinafter provided, this Zoning Ordinance shall not apply to structure or uses lawfully in existence or lawfully begun, or to a building permit or special permit issued before the first publication of notice of the public hearing of the Planning Board on such ordinance required by § 9.22, but shall apply to any change or substantial extension of such use, to a building or special permit issued after the first notice of said public hearing, to any reconstruction, extension or structural change of such structure and to any alteration of a structure begun after the first notice of said public hearing to provide for its use or a substantially different purpose or for the same purpose in a substantially different manner or to a substantially greater extent except where the alteration, reconstruction, extension or structural change to a single or two family residential structure or building does not increase the non-conforming nature of said structure or building and does not further violate any other applicable provisions of this Zoning Ordinance. Pre-existing non-conforming uses may be changed or extended and pre-existing non-conforming structures or buildings may also be extended as provided by Massachusetts General Laws Chapter 40A, Section 6, provided that no such change, extension, structural change or alteration shall be permitted unless there is a Special Permit Finding by the Board of Appeals that such change, extension or alteration shall not be substantially more detrimental than the existing non-conforming use, structure or building to the neighborhood;

Notwithstanding subsection (a) above, a non-conforming single or two family residential structure may be altered, reconstructed, extended or changed if the proposed alteration, reconstruction, extension or change complies with the Table of Dimensional Regulations (§ 5.04).

A nonconforming building, structure or use may be extended, altered or changed to make it conform with the provisions of this Zoning Ordinance.

A nonconforming building, structure or use may be extended, altered or changed as may be ordered by the Inspector of Buildings to make it safe in accordance with § 121 of the State Building Code.

A non-conforming use may be replaced by another non-conforming use, at least as restricted in Article V as the existing use, subject to the Board of Appeals finding as provided in § 4.06(a).

Where a non-conforming use has been changed to a more restricted use, it shall not again be changed to a less restricted use.

A non-conforming use of a building or land which has been abandoned for a period of two years shall not thereafter be returned to such non-conforming use. A non-conforming use shall be considered abandoned when the intent of the owner to discontinue the use is apparent or when the premises have been vacant for two years or when the characteristic equipment and/or furnishings of the non-conforming use have been removed from the premises and have not been replaced by similar equipment, whichever shall first occur.

No non-conformity shall be increased in area or degree of non-conformity beyond the state existing prior to the catastrophe, as determined by the Zoning Enforcement Officer, subject to the provisions of § 4.06(a);

Such reconstruction or restoration shall commence within twelve months of such catastrophe unless the Board of Appeals shall extend such period.

The regulations for each district pertaining to the size and dimensions of the lot and of the buildings thereon and to the placement of the buildings and of accessory uses on the lot shall be as specified in Article V, subject to further provisions of Article IV.

The lot or yard areas required for any building or use shall not include any part of a lot that is required by any other building or use to comply with any requirements of the Zoning Ordinance.

No lot, or buildings or structures thereon, shall be changed in size or shape so as to violate the provisions of this Zoning Ordinance, except that where there are two or more existing detached dwellings on a single lot, the lot may be divided into as many lots as there are dwellings, provided each lot complies with the requirements of § 4.09.

Land or structures used for religious or educational purposes, as defined by Chapter 40A, Section 3 of the General Laws of Massachusetts, shall be subject to the same regulations concerning the bulk or height of structures, yard sizes, lot area, setbacks, open space, parking, and building coverage as those required under any provision of this Zoning Ordinance regulating the foregoing conditions for the district within which the use is proposed.

Cornices, eaves, attached chimneys, and bay windows projecting no more than two feet shall be permitted. Exterior uncovered stairways, covered and uncovered (but not enclosed, glazed, or screened) entrance porticoes, stoops, vestibules, bulkheads, first floor open-air porches, and cantilevered balconies are permitted as long as they project no more than four feet into any setback. Also, bays less than or equal to 20% of the total facade abutting the Build- to Line are permitted to project into the Build-to-Line Setback by four feet. Enclosed decks and porches, attached carports, covered walks and the like shall not be exempted from Setback requirements, except as provided in § 4.03(c) and 4.03(d). Further, in all residential districts air conditioning equipment/structures and similar equipment/structures shall be permitted within the required side yard setback if said equipment or structure is no less than five feet from the property line of the abutting property.

No use other than landscaping outdoor dining, public art, sidewalks, multi-use paths, and permitted signs shall be permitted in the front yard of any lot subject to the provisions of § 6.03 and Article VII. Parking within the front yard is expressly prohibited.

No use other than landscaping and accessory parking of not more than three cars is permitted within a required side or rear yard in any residence district except as provided in § 4.12 unless screened as provided in § 4.14 and subject to the provisions of § 6.02(k). In LB, WSQ, NMU and I districts, required side and rear yards may be used for any permitted outdoor accessory use, subject to the provisions of Articles VI and VII.

Exceptions to build-to-line Requirements.

A build-to-line may be increased as specified below for purposes of amenities such as a plaza, square, courtyard, recessed entrance, sidewalk, multi-use path, raised terrace, facade offsets pursuant to § 5.05(f) or outdoor dining, but not intended for automobile use.

For components of a project in keeping with the adopted Design Guidelines, an increased Build-to Line may be required by the SPGA or requested by an applicant if it is found that the strict adherence to the Build-to-Line is inconsistent with adopted Design Guidelines and development pattern, as determined by the SPGA or is required pursuant to § 5.05(f).

The Build-to Line may allow for averaging a building's setback from the property line to accommodate changes in building facade and irregular property boundaries, but no area of a building shall encroach by more than 10% of the required setback.

Exceptions to Side Yard Setback Requirements. Developments in the NB, LB, NMU, WSQ, I-1, I-2, I-3, RMUD, and PSCD Districts may be contiguous on a block: zero lot line and/or shared party wall. Corner lots may be developed with two front yards with yards determined by the Zoning Enforcement Officer.

Front Yard: In a LB, NB, NMU, WSQ, or any Industrial district no building shall be erected nearer to the street line or established building line than is permitted in the adjacent Residence District within a distance of 50 feet from the Residence District boundary line, except where such building is separated by a street from the Residence District.

Side Yard: In a LB, NB, or any Industrial district, no building shall be erected within 10 feet of the side lot line of any abutting lot, all or the majority portion of which is a Residence.