A. 
No structure shall be erected or used or land used except as set forth in the Use Regulation Schedule[1] or in § 195-6, Accessory uses, unless exempted by this chapter or by statute. Uses not expressly provided for herein are prohibited. Not more than one principal structure shall be placed on a lot, except in accordance with § 195-12.
[1]
Editor's Note: The Use Regulation Schedule is included as an attachment to this chapter.
B. 
When an activity might be classified under more than one of the uses on the Use Regulation Schedule, the more specific classification shall govern; if equally specific, the more restrictive shall govern.
Any use permitted as a principal use is also allowed as an accessory use, as are others customarily accessory and incidental to permitted principal uses. Accessory uses are permitted only in accordance with lawfully existing principal uses. An accessory use may not, in effect, convert a principal use to a use not permitted in the zoning district in which it is located. Where a principal use is permitted under special permit, its accessory use is also subject to the special permit. In all instances where site plan review and approval are required for a principal use, the addition of any new accessory use to the principal use, where such addition exceeds the thresholds established in § 195-104, shall also require site plan review and approval.
A. 
Accessory scientific uses. Uses, whether or not on the same parcel as activities permitted as a matter of right, which are necessary in connection with scientific research or scientific development or related production may be permitted upon the issuance of a special permit by the Board of Appeals, provided that the Board finds that the proposed use does not substantially derogate from the public good.
B. 
Major recreational equipment. No major unregistered recreational equipment shall be stored on any lot in a residential district other than in a carport or enclosed building or behind the building line of the principal building; provided, however, that such equipment may be parked anywhere on residential premises for a period not to exceed 72 hours. No such equipment shall be used for living or housekeeping purposes when stored on a residential lot or in any location not approved for such use. All equipment which does not conform to these regulations shall be considered nonconforming.
C. 
Family day-care homes. Family day-care home providers shall be registered with and have obtained all applicable licenses from the Commonwealth of Massachusetts Office of Children and shall be in full compliance with all applicable rules and regulations promulgated by the Office of Children as set forth in accordance with MGL c. 28A, particularly §§ 9 through 13 thereof, and in accordance with Section 13 of Chapter 785 of the Acts of 1972. Providers shall also comply with the provisions of the Life Safety Code adopted by the National Fire Protection Association, Section 10-9, Family Child Day-Care Homes, and any amendments or revisions thereto or act in relation thereto.
D. 
Barn sale, yard sale, garage sale or flea market. The temporary use of residential, institutional or industrial premises for the sale of personal property is permitted, provided that a temporary occupancy permit is obtained. Such permits shall be issued by the Inspector of Buildings for up to two consecutive days only, not more than twice each calendar year for any given premises. For each such sale a separate permit shall be required. No merchandise dangerous to life or limb shall be shown or sold, and all persons conducting such sales shall take all necessary steps for the protection of persons while on their premises.
E. 
Up to two cattle, horses, sheep, hogs, goats, or similar livestock may be maintained accessory to a dwelling only on a lot having an area not less than 40,000 square feet. An additional 15,000 square feet is required per large farm animal in excess of the first two. Such animals and their wastes shall be contained at least 50 feet from any abutting lot line of a residentially used lot and at least 50 feet from any year-round surface water body.
[Amended 10-16-2017 by ATM, Art. 20; 2-4-2019 STM by Art. 1]
[Added 10-15-2001 ATM by Art. 19; amended 10-18-2010 ATM by Art. 18; 1-27-2025 STM by Art. 1; 10-23-2025 ATM by Art. 31]
A. 
Objectives.
(1) 
To comply with the State Zoning Act, MGL c. 40A, § 3 and regulations adopted thereunder;
(2) 
To provide for flexibility within the existing Zoning Bylaw to afford an opportunity to accommodate additional living arrangements;
(3) 
To plan for changing demographics and economic climate;
(4) 
To increase the supply of affordable housing;
(5) 
To ensure compliance with building, safety, fire code standards and zoning provisions.
B. 
Definitions. The following definitions shall apply to this ADU Bylaw:
ACCESSORY DWELLING UNIT (ADU)
A self-contained housing unit, inclusive of sleeping, cooking, and sanitary facilities located on the same lot as a principal dwelling, either attached or detached from the principal dwelling and accessory to that dwelling, that maintains a separate entrance, either directly from the outside or through an entry hall or corridor shared with the principal dwelling sufficient to meet the requirements of the state building code for safe egress.
The definitions set forth in 760 CMR 71.0 et seq., as it may be amended, shall apply to all terms of this ADU Bylaw not expressly defined herein.
C. 
Applicability/eligibility.
(1) 
An accessory dwelling unit is allowed by right as accessory to a principal dwelling in each zoning district where single-family dwellings are expressly permitted or otherwise lawfully allowed, as set forth in the Use Regulation Schedule,[1] § 195-5 and otherwise.
[1]
Editor's Note: Said schedule is included as an attachment to this chapter.
(2) 
A building permit application for an ADU shall be filed with the Building Commissioner. Architectural floor plans for the principal dwelling, with dimensions and calculations for gross floor area, and proposed ADU, with dimensions and gross floor area, and a certified site survey for the existing and proposed footprint/building locations, with setback dimensions, Floor area ratio and lot coverage calculations, shall be submitted in order for the Building Commissioner to determine compliance with Subsections C(3) and Section D.
(3) 
The ADU shall comply with the dimensional standards applicable for the district in which the ADU is located, as set forth in the Table of Dimensional Requirements, Attachment 2, except as may be otherwise set forth herein. For purposes of applying such requirements, ADU's shall be considered part of the principal dwelling to which they are accessory, and not as a separate accessory building or structure under § 195-11 or otherwise. Where the ADU does not comply with such dimensional standards, the applicant may seek relief in accordance with the Zoning Bylaws.
(4) 
Where the principal dwelling is a nonconforming single or two family structure, the ADU shall meet the requirements of § 195-8E as applied by the Building Commissioner and the Board of Appeals as set forth therein, and where the principal dwelling is a nonconforming multi-family (3 or more units) structure, the ADU shall meet the requirements of § 195-8C, as applied by the Planning Board, provided that in either instance a special permit shall not be required, and when a determination is required such determination shall not be subject to special permit criteria and shall be made by majority vote.
(5) 
An ADU for a multi-family principal dwelling (three or more units), shall be subject to Minor Site Plan Review, per § 195-104G.
(6) 
Proposed ADUs that comply with the requirements of Subsection C and Subsection D shall be granted a building permit.
D. 
Design and Use standards.
(1) 
Ingress, egress, access for ADU within and attached. Adequate provision, as determined by the Building Inspector, shall be provided for separate ingress and egress to the ADU. To the extent possible, common/shared entryways should be utilized, rather than exterior passageways and accessways. New exterior doorways for the ADU should be located to the side or rear of the single- family dwelling. Staircases, serving a second or third floor, shall be enclosed.
(2) 
Detached. Consistent with § 195-11, detached ADU's shall not be located within the required front yard area.
(3) 
Area limitation. An ADU shall be limited to a maximum of 900 square feet of gross floor area or 1/2 the gross floor area of the principal dwelling, whichever is smaller.
(4) 
Parking. Not more than one additional off-street parking space shall be required for each ADU, provided that where the ADU will be accessory to a principal dwelling located within 0.5 miles of a commuter rail station, subway station, ferry terminal or bus station, as those terms may be defined by regulations adopted for ADU's pursuant to MGL c. 40A, § 3, no additional off-street parking space shall be required. An off-street parking space shall have vehicular access to the existing driveway. A separate driveway shall not be permitted for an ADU.
(5) 
No new curb cut shall be permitted for an ADU.
(6) 
The construction of any ADU must be in conformity with the Mass State Building and Fire Codes and any other local bylaws and regulations including but not limited to the Department of DPW's Sewer Capacity and Connection Restrictions and Board of Health regulations as applicable.
(7) 
The use of the ADU for short term rentals, as defined in MGL c. 64G, § 1, shall be prohibited.
(8) 
ADU's shall provide adequate provisions for emergency services via a hard surface (paved, brick, concrete) walkway from the ADU to a walkway for the existing single family and/or a walkway with a connection directly to a roadway and identifiable from the street via mailboxes and/or address numbering on the building.
(9) 
Prior to issuance of an occupancy permit, the ADU shall apply to the E-911 committee, via the Town Clerk's office, to obtain official addressing.
[Amended 10-21-2013 ATM by Art. 13]
A. 
Home occupations as of right. Businesses or professions incidental to and customarily associated with the principal residential use of premises may be engaged in as an accessory use by a resident of that dwelling; provided, however, that all of the following conditions shall be satisfied:
(1) 
The occupation or profession shall be carried on wholly within the principal building or within a building or other structure accessory thereto which has been in existence at least five years, without extension thereof.
(2) 
Not more than 25% of the combined gross floor area, not to exceed a maximum of 500 gross square feet, of the residence and any qualified accessory structures shall be used in the home occupation. The gross square feet shall be calculated based upon square feet principally used for the home occupation. Common areas within the principal structure shall not be included in this calculation. In calculating gross floor area for the purposes of a home occupation, the provisions of this section shall prevail over those in § 195-108 (floor area, gross).
(3) 
No person not a member of the household shall be employed at the home occupation site.
(4) 
The home occupation shall not serve clients, customers, salespersons or the like on the premises with the exception of individualized services not to exceed four visits per day and the visits cannot occur concurrently. Business hours shall be from 8:00 a.m. to 8:00 p.m., Monday through Saturday.
(5) 
There shall be no sign or exterior display, no exterior storage of materials and no other exterior indication (such as but not limited to noise, smoke, dust, odor, vibrations) of the home occupation or other variation from the residential character of the premises, including, but not limited to, alterations to utility services which may not be increased beyond that which is required for residential structures of similar size.
(6) 
No use or storage of hazardous materials in quantities greater than associated with normal household use shall be permitted.
(7) 
Traffic generated shall not exceed volumes normally expected in a residential neighborhood.
(8) 
No more than two commercial motor vehicles, including trailers, provided:
(a) 
That total combined gross vehicle weight does not exceed 20,000 pounds.
(b) 
That any single vehicle does not exceed 14,000 pounds.
(c) 
That vehicles be parked within an existing paved driveway (off-street).
(9) 
By-right home occupations shall be required to apply for a business certificate with the Town Clerk.
B. 
Home occupations by special permit. All non as-of-right businesses or professions incidental to and associated with the principal residential use of premises may be engaged in as an accessory use by a resident of that dwelling upon the issuance of a special permit by the Board of Appeals; provided, however, that all of the following conditions shall be satisfied:
(1) 
All of the requirements of Subsection A(1), (2), (4) and (5), unless noted below.
(2) 
Not more than one person not a member of the household shall perform work in the home occupation at any one time.
(3) 
An unlighted sign of not more than three square feet in area may be permitted. The visibility of exterior storage of materials and other exterior indications of the home occupation, or other variation from the residential character of the premises, shall be minimized through screening and other appropriate devices.
(4) 
Parking generated by the home occupation shall be accommodated off street, other than in a required front yard, and shall not occupy more than 20% of the lot area. In granting a special permit, the Board of Appeals may consider the use of on-street parking if it finds that the neighborhood will not be adversely impacted.
(5) 
The use or storage of hazardous materials in quantities greater than associated with normal household use shall be subject to design requirements to protect against discharge to the environment.
(6) 
No more than two commercial motor vehicles, including trailers, may be parked in the driveway, provided that:
(a) 
The motor vehicles, including any associated trailers, do not exceed a total combined 28,000 pounds' gross vehicle weight;
(b) 
The motor vehicles shall not be heavy construction equipment/apparatus;
(c) 
The motor vehicles are not loaded in whole or in part with noxious, flammable, dangerous or offensive materials or liquids.
C. 
Special permits by the Zoning Board.
(1) 
A special permit may be issued to waive Subsection A(1) to allow for a building that is less than five years old to be considered for the home occupation, provided the structure was an existing structure and not constructed solely for the home occupation.
(2) 
A special permit may be issued to waive Subsection A(2) to allow a greater area for the home occupation, but this area shall not exceed 50% of the allowable square-foot area allowed in Subsection A(2).
(3) 
A special permit may be issued to waive Subsection A(5) if it is determined that a sign not to exceed two square feet or any exterior alteration associated with the household occupation will not detract from the character of the neighborhood or the residential structure.
(4) 
A special permit may only be granted to the current homeowner, shall be personal to that person, and shall not be transferable upon the sale of the property.
(5) 
A special permit may be issued to waive Subsection A(4) to allow additional visits up to a total of eight per day, which cannot occur concurrently.
A. 
Applicability. This chapter shall not apply to structures or uses lawfully in existence or lawfully begun or to a building or special permit issued before the first publication of notice of the public hearing required by MGL c. 40A, § 5 at which this chapter, or any relevant part thereof, was adopted. Such prior lawfully existing nonconforming uses and structures may continue, provided that no modification of the use or structure is accomplished, unless authorized hereunder. For the purposes of § 195-8B and § 195-8C, the Board, of Appeals shall be the special permit granting authority for single- and two-family dwellings and the Planning Board shall be the special permit granting authority for all other uses and structures, including multifamily and nonresidential uses and structures.
[Amended 10-20-2008 ATM by Art. 12]
B. 
Nonconforming uses. The Board of Appeals or the Planning Board, as applicable, may award a special permit to change a nonconforming use in accordance with this section only if it determines that such change or extension shall not be substantially more detrimental than the existing nonconforming use to the neighborhood. The following types of changes to nonconforming uses may be considered by the Board of Appeals:
[Amended 10-20-2008 ATM by Art. 12]
(1) 
Change or substantial extension of the use.
(2) 
Change from one nonconforming use to another, less detrimental, nonconforming use.
C. 
Nonconforming structures (except one- and two-family structures). The Board of Appeals or the Planning Board, as applicable, may award a special permit to reconstruct, extend, alter or change, including the extension of an exterior wall at or along the same nonconforming line, parallel to the required setback, of a nonconforming structure in accordance with this section only if it determines that such reconstruction, extension, alteration or change shall not be substantially more detrimental than the existing nonconforming structure to the neighborhood. The following types of changes to nonconforming structures may be considered by the Board of Appeals or the Planning Board, as applicable:
[Amended 10-20-2008 ATM by Art. 12; 4-30-2012 ATM by Art. 28]
(1) 
Reconstructed, extended or structurally changed.
(2) 
Altered to provide for a substantially different purpose or for the same purpose in a substantially different manner or to a substantially greater extent.
(3) 
Reconstructed after a catastrophe, provided that the owner shall apply for a building permit and start operations for reconstruction on said premises within two years after such catastrophe, and provided that the building(s) as reconstructed shall be only as great in volume or area as the original nonconforming structure.
D. 
Variance required. Except as provided for in Subsections C and E, the reconstruction, extension or structural change of a nonconforming structure in such a manner as to increase an existing nonconformity, or create a new nonconformity, shall require the issuance of a variance from the Board of Appeals.
[Amended 4-30-2012 ATM by Art. 28]
E. 
By-right nonconforming single- and two-family residential structures. Nonconforming single- and two-family residential structures may be reconstructed, extended, altered or structurally changed (the work) upon a determination by the Inspector of Buildings that such proposed reconstruction, extension, alteration or change does not increase the nonconforming nature of said structure.
[Amended 4-30-2012 ATM by Art. 28; 10-28-2019 ATM by Art. 25]
(1) 
The following circumstances, Subsection E(1)(a) through (d), shall not be deemed to increase the nonconforming nature of said structure.
(a) 
Conformance to historical dimensional requirements based upon year structure was built and zoning district*:
Date Structure Built
Front
Side
Rear
1938 to May 10, 1954
25
10
10
May 11, 1954, to June 1956
25
12
10
July 1956 to May 1, 1961
R.A.1
40
25
30
R.A.2
35
17
35
R.A.3
30
15
35
GR
30
12
30
June 1961 to present
RA
40
25
30
RB
40
25
30
RC
20
12
20
*
Year built is based upon Assessors database or best available information presented to the Building Commissioner. Historical Zoning Maps are on file with the Community Development and Building Departments.
(b) 
Insufficient lot area. The work to a structure located on a lot with insufficient lot area which complies with setback requirements per Subsection E(1)(a);
(c) 
Insufficient frontage. The work to a structure located on a lot with insufficient frontage which complies with setback requirements per Subsection E(1)(a);
(d) 
Other dimensional requirements. The work to a structure which complies with Subsection E(1)(a) through (c) above and also complies with current building coverage, and building height and FAR requirements. Extension of the nonconforming structure along the same nonconforming line, parallel to the required setback, shall not be deemed to increase the nonconforming nature of said structure.
(2) 
Special permit for nonconforming single- and two-family residential structures. In the event that the Building Commissioner determines that a by-right building permit can not be issued per Subsection E, as the nonconforming nature of such structure would be increased by the proposed reconstruction, extension, alteration or change or a new nonconformity created, the Board of Appeals may, by special permit, allow such reconstruction, extension, alteration or change where it determines that the proposed modification will not be substantially more detrimental than the existing nonconforming structure to the neighborhood.
[Added 4-24-2023 ATM by Art. 19]
F. 
Abandonment or nonuse. A nonconforming use or structure which has been abandoned, or not used for a period of two years, shall lose its protected status and be subject to all of the provisions of this chapter.
G. 
Reversion to nonconformity. No nonconforming use shall, if changed to a conforming use, revert to a nonconforming use.
[Amended 4-29-2013 ATM by Art. 25]
A. 
Purpose. By vote at the state election on November 6, 2012, the voters of the commonwealth approved a law regulating the cultivation, distribution, possession and use of marijuana for medical purposes. The law provides that it is effective on January 1, 2013, and the State Department of Public Health is required to issue regulations regarding implementation within 120 days of the law's effective date. Currently under the Zoning Bylaw, a medical marijuana treatment center is a permitted use in the Town of Chelmsford and any regulations promulgated by the State Department of Public Health are expected to provide guidance to the Town in regulating medical marijuana, including medical marijuana treatment centers. The regulation of medical marijuana raises novel and complex legal, planning, and public safety issues, and the Town needs time to study and consider the regulation of medical marijuana treatment centers and address such novel and complex issues, as well as to address the potential impact of the state regulations on local zoning and to undertake a planning process to consider amending the Zoning Bylaw regarding regulation of medical marijuana treatment centers and other uses related to the regulation of medical marijuana. The Town intends to adopt a temporary moratorium on the use of land and structures in the Town for medical marijuana treatment centers so as to allow the Town sufficient time to engage in a planning process to address the effects of such structures and uses in the Town and to enact bylaws in a manner consistent with sound land use planning goals and objectives.
B. 
Definitions. As used in this section, the following terms shall have the meanings indicated:
MEDICAL MARIJUANA TREATMENT CENTER
A not-for-profit entity, as defined by Massachusetts law only, registered by the Department of Public Health, that acquires, cultivates, possesses, processes (including development of related products such as food, tinctures, aerosols, oils or ointments), transfers, transports, sells, distributes, dispenses, or administers marijuana, products containing marijuana, related supplies, or educational materials to qualifying patients or their personal caregivers.
C. 
Temporary moratorium.
(1) 
For the reasons set forth above and notwithstanding any other provision of the Zoning Bylaw to the contrary, the Town hereby adopts a temporary moratorium on the use of land or structures for a medical marijuana treatment center.
(2) 
The moratorium shall be in effect through June 30, 2014.
(3) 
During the moratorium period, the Town shall undertake a planning process to address the potential impacts of medical marijuana in the Town, consider the Department of Public Health regulations regarding medical marijuana treatment facilities and related uses, and shall consider adopting new Zoning Bylaws to address the impact and operation of medical marijuana treatment centers and related uses.