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2024 Attorney General Approval Letter re: Special Town Meeting Articles 6 and 8 pdf file
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LEGAL NOTICE Pursuant to Chapter 40, Section 32 of the General Laws of the Commonwealth, the following Articles were partially approved by the Attorney General’s Office relative to the following amendments to the Zoning Bylaw adopted at Canton’s Special Town Meeting held on November 18, 2024. Article 6 - Amend Zoning Bylaw Section 11.0 Definitions Article 8 - Amend Zoning Bylaw Section 8.0 by replacing existing section with a new section entitled ACCESSORY DWELLING UNITS Any claim of invalidity by reason of any defect in the procedure of adoption or amendment to the Zoning By-Law may only be made with 90 days of the second publication. DATE OF ATTORNEY GENERAL’S DECISION LETTER: June 4, 2025 DECISION RECEIVED BY THE TOWN CLERK: June 9, 2025 CANTON CITIZEN PUBLICATION DATES: June 19 & June 26, 2025 Copies of the Attorney General’s decision and the approved bylaw changes are available for examination by the public in the office of the Town Clerk, 801 Washington Street, Canton and on the Town website at https://www.town.canton.ma.us/260/Attorney-General-Approval-Letter Tracy K. Kenney, Town Clerk
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The Commonwealth of Massachusetts
Office of the Attorney General
Central Massachusetts Division
10 Mechanic Street, Suite 301
Worcester, MA 01608
Andrea Joy Campbell
(508) 792-7600
Attorney General (508) 795-1991 fax
www.mass.gov/ago
June 4, 2025
Tracy K. Kenney, Town Clerk
Town of Canton
801 Washington Street
Canton, MA 02021
Re: Canton Special Town Meeting of November 18, 2024 — Case # 11654
Warrant Articles # 6, 7, 8, 9, and 10 (Zoning)1
Dear Ms. Kenney:
Articles 6 and 8 - Under Article 6 the Town voted to amend Section 11.0, “Definitions,”
to add or amend several definitions including adding a new definition for the term “Accessory
Dwelling Unit.” Under Article 8 the Town voted to delete Section 8.1, “Accessory Apartments,”
and insert a new Section 8.1, “Accessory Dwelling Units,” (“ADU”) to allow ADUs as-of-right in
compliance with G.L. c. 40A, § 3 and the implementing Regulations promulgated by the Executive
Office of Housing and Livable Communities (“EOHLC”), 760 CMR 71.00, “Protected Use
Accessory Dwelling Units” (“Regulations”).2
We partially approve Articles 6 and 8 because the approved text does not conflict with state
law. However, we disapprove the following provisions because they conflict with G.L. c. 40A, §
3 and the Regulations (see Amherst v. Attorney General, 398 Mass. 793, 795-96 (1986) (requiring
inconsistency with state law or the Constitution for the Attorney General to disapprove a by-law)):
• references to “single-family” dwelling in Sections 8.14; 8.16 (A) and (C) and 11.0;
• Section 8.1.2 that limits an as-of-right ADU only where single-family homes are
allowed as-of-right;
• Section 8.1.2 (B) that imposes a minimum lot size requirement for construction of
1 In a decision issued March 10, 2025, we approved Articles 7, 9, and 10, and by agreement with Town
Counsel we extended our deadline for review of Articles 6 and 8 for 60 days until May 9, 2025. On May 8,
2025, by agreement with Town Counsel, we extended the deadline for our decision on Articles 6 and 8 for
an additional 30 days until June 8, 2025.
2 The Regulations can be found here: https://www.mass.gov/doc/760-cmr-7100-protected-use-adus-fmal-
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an ADU;
• a portion of Section 8.1.2 (D) that imposes a setback requirement that is the same
setback requirement as the primary residence; and
• a portion of Section 8.1.6’s parking requirements.
In this decision we summarize the by-law amendments adopted under Articles 6 and 8;
discuss the Attorney General’s standard of review of town by-laws and the recent statutory and
regulatory changes that allow Protected Use ADUs as-of-right;3 and then explain why, based on
our standard of review, we partially approve the zoning by-law amendments adopted under
Articles 6 and 8.4 In addition, we offer comments for the Town’s consideration regarding certain
approved provisions adopted under Articles 6 and 8.
I. Summary of Articles 6 and 8
A. Article 6
Under Article 6, the Town voted to amend its zoning by-laws, Section 11.0, “Definitions,”
to amend or add definitions related to accessory uses. One change amends the definition of
“Accessory Apartment,” as follows (new text in bold and deleted text in strikethrough):
Accessory Apartment: A-secondary dwelling unit located within a detached single
family dwelling. The accessory apartment shall be subordinate to the principal unit
and separated from it in a manner that maintains the appearance of the structure as
a single family house. A preexisting nonconforming dwelling unit created in a
single-family dwelling by special permit granted by the zoning board of
appeals and recorded at the Norfolk county registry of deeds prior to the
adoption of An Act Relative to the Affordable Homes Act by the 193rd
Massachusetts General Court on August 6, 2024.
Another change amends the definition of “Accessory Building” to delete the word
“building” and insert the word “structure” so that as amended, it provides: “Accessory Structure:
A subordinate structure located on the same lot as the main, or principal building or principal use,
the use of which is customarily incidental to that of the principal building or use of the land.” The
next change adds a definition for the term “Lot Coverage” as follows: “The portion of a lot,
3 760 CMR 71.02 defines the term “Protected Use ADU” as follows: “An attached or detached ADU that
is located, or is proposed to be located, on a Lot in a Single-family Residential Zoning District and is
protected by M.G.L. c. 40A, § 3, provided that only one ADU on a lot may qualify as a Protected Use ADU.
An ADU that is nonconforming to Zoning shall still qualify as a Protected Use ADU if it otherwise meets
this definition.”
4 We acknowledge that the Town adopted Articles 6 and 8 at its November 2024 Special Town Meeting,
which was well before EOHLC finalized its Regulations and therefore the Town did not have the benefit
of the Regulations’ requirements when it adopted Articles 6 and 8.
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expressed as a percentage, that is occupied by buildings or structures, including accessory
structures.”
Finally, under Article 6 the Town added a new definition for “Accessory Dwelling Unit”
as follows:
Accessory Dwelling Unit: A secondary dwelling unit, but not a mobile home,
located either within or on the same lot as a detached single-family dwelling. The
accessory dwelling unit shall be subordinate in size to the principal dwelling unit
and separated from it in a manner that maintains the appearance of the structure as
a single-family house.
B. Article 8
Under Article 8 the Town voted to amend its zoning by-laws by deleting Section 8.1,
“Accessory Apartments,” in its entirety and inserting a new Section 8.1, “Accessory Dwelling
Units,” that regulates ADUs.
Section 8.1.1, “Purpose,” provides several purposes of the new Section 8.1 including: (1)
to provide for housing options that reduce maintenance costs and are more affordable than
traditional single-family dwellings; (2) to provide for the development of a range of housing types;
and to (3) facilitate housing production, diversity, and affordability in the Town’s neighborhoods.
Section 8.1.2, “Limitations on Use,” allows ADUs as-of-right, but imposes restrictions on their
use, in relevant part as follows, with emphasis added:
One Accessory Dwelling Unit (ADU) shall be allowed as-of-right in all zoning
districts in which single-family homes are allowed as-of-right subject to the
following restrictions:
B. The Lot contains a minimum of 5,000 square feet of area;
***
D. The ADU is subject to the same dimensional setbacks as the primary
residence, as provided in Section 4.0 of this Zoning By-law;
Section 8.1.3, “Additional Accessory Dwelling Units,” authorizes the Board of Appeals to
grant a special permit for additional ADUs (beyond one) located on the same lot as the as-of-right
ADU. Section 8.1.4, “Exterior Appearance of a Dwelling with an ADU,” imposes exterior design
standards on Protected Use ADUs as follows (with emphasis added):
The ADU shall be designed so that the appearance of the structure remains that of
a single-family dwelling, subject further to the following requirements:
A. All stairways to the second or third stories shall be enclosed within the
exterior walls of the dwelling;
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B. Any new, additional entrance to an existing dwelling shall be located on the
side or in the rear of the dwelling; and
C. Where there are two (2) or more existing entrances on the front facade of a
dwelling, if modifications are made to any entrance, the result shall be that one (1)
appears to be the principal entrance and other entrances appear to be secondary.
Section 8.1.5, “Dimensional Requirements,” requires the ADU to comply with “all
applicable dimensional requirements in Section 4.0 of the Town of Canton Zoning By-laws.”
Section 8.1.6, “Parking,” imposes parking requirements on the ADU as follows (with emphasis
added):
A. There shall be a minimum of one (1) off-street parking space per ADU in
addition to the parking spaces that are required by the underlying zoning district for
the single-family residence;
B. No additional parking spaces over and above that of the underlying zoning
district shall be required if the ADU is located within 0.5 miles from a commuter
rail station, subway station, ferry terminal, or bus station;
C. A single driveway shall serve both the single-family residential structure
and the ADU, provided that a detached ADU may have a separate parking area.
Finally, Section 8.1.7, “Severability,” provides that if any provision of Section 8.1 is found
invalid by a court of competent jurisdiction, the remainder of Section 8.1 shall not be affected.
II. Attorney General’s Standard of Review of Zoning By-laws
Our review of Articles 6 and 8 is governed by G.L. c. 40, § 32. Under G.L. c. 40, § 32, the
Attorney General has a “limited power of disapproval,” and “[i]t is fundamental that every
presumption is to be made in favor of the validity of municipal by-laws.” Amherst, 398 Mass, at
795-96. The Attorney General does not review the policy arguments for or against the enactment.
Id. at 798-99 (“Neither we nor the Attorney General may comment on the wisdom of the town’s
by-law.”) “As a general proposition the cases dealing with the repugnancy or inconsistency of
local regulations with State statutes have given considerable latitude to municipalities, requiring a
sharp conflict between the local and State provisions before the local regulation has been held
invalid.” Bloom v, Worcester, 363 Mass. 136, 154 (1973). “
Articles 6 and 8, as amendments to the Town’s zoning by-laws, must be given deference.
W.R. Grace & Co. v. Cambridge City Council, 56 Mass. App. Ct. 559, 566 (2002) (“With respect
to the exercise of their powers under the Zoning Act, we accord municipalities deference as to
their legislative choices and their exercise of discretion regarding zoning orders.”). When
reviewing zoning by-laws for consistency with the Constitution or laws of the Commonwealth, the
Attorney General’s standard of review is equivalent to that of a court. “[T]he proper focus of
review of a zoning enactment is whether it violates State law or constitutional provisions, is
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arbitrary or unreasonable, or is substantially unrelated to the public health, safety or general
welfare.” Durand v. IDC Bellingham, LLC, 440 Mass. 45, 57 (2003). “If the reasonableness of a
zoning bylaw is even ‘fairly debatable, the judgment of the local legislative body responsible for
the enactment must be sustained.’” Id. at 51 (quoting Crall v. City of Leominster, 362 Mass. 95,
101 (1972)). However, a municipality has no power to adopt a zoning by-law that is “inconsistent
with the constitution or laws enacted by the [Legislature].” Home Rule Amendment, Mass. Const,
amend, art. 2, § 6.
III. Summary of Recent Legislative Changes Regarding ADUs
On August 6, 2024, Governor Healey signed into law the “Affordable Homes Act,”
Chapter 150 of the Acts of 2024 (the “Act”). The Act includes amendments to the State’s Zoning
Act, G.L. c. 40A, to establish ADUs as a protected use subject to limited local regulation including
amending G.L. c. 40A, § 1A to add a new definition for the term “Accessory dwelling unit” and
amending G.L. c. 40A, § 3 (regarding subjects that enjoy protections from local zoning
requirements, referred to as the “Dover Amendment”), to add a new paragraph that restricts a
zoning by-law from prohibiting, unreasonably regulating or requiring a special permit or other
discretionary zoning approval for the use of land or structures for a single ADU. The amendment
to G.L. c. 40A, § 3, to include ADUs means that ADUs are now entitled to statutory protections
from local zoning requirements.
On January 31, 2025, the EOHLC promulgated regulations for the implementation of the
legislative changes regarding ADUs. See 760 CMR 71.00, “Protected Use Accessory Dwelling
Units.”5 The Regulations define key terms and prohibit certain “Use and Occupancy Restrictions”
defined in Section 71.02 as follows:
Use and Occupancy Restrictions. A Zoning restriction, Municipal regulation,
covenant, agreement, or a condition in a deed, zoning approval or other requirement
imposed by the Municipality that limits the current, or future, use or occupancy of
a Protected Use ADU to individuals or households based upon the characteristics
of, or relations between, the occupant, such as but not limited to, income, age,
familial relationship, enrollment in an educational institution, or that limits the
number of occupants beyond what is required by applicable state code.
While a municipality may reasonably regulate a Protected Use ADU in the manner
authorized by 760 CMR 71.00, such regulation cannot prohibit, require a special permit or other
discretionary zoning approval for, or impose a “Prohibited Regulation”6 or an “Unreasonable
5 See the following resources for additional guidance on regulating ADUs: (1) EOHLC’s ADU FAQ section
(https://www.mass.gov/info-details/accessory-dwelling-unit-adu-faqsV ); (2) Massachusetts Department of
Environmental Protection’s Guidance on Title 5 requirements for ADUs
(https://www.mass.gov/doc/guidance-on-title-5-310-cmr-15000-compliance-for-accessory-dwelling-
units/download); and (3) MassGIS Addressing Guidance regarding address assignments for ADUs
(https://www.mass.gov/info-details/massgis-addressing-guidance-for-accessory-dwelling-units-adus ).
6 760 CMR 71.03 prohibits a municipality from subjecting the use of land or structures on a lot for a
Protected Use ADU to any of the following: (1) owner-occupancy requirements; (2) minimum parking
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Regulation” on, a Protected Use ADU. See 760 CMR 71.03, “Regulation of Protected Use ADUs
in Single-Family Residential Zoning Districts.”7 Moreover, Section 71.03 (3)(a) provides that
while a town may reasonably regulate and restrict Protected Use ADUs, certain restrictions or
regulations “shall be unreasonable” in certain circumstances.8 In addition, while municipalities
may impose dimensional requirements related to setbacks, lot coverage, open space, bulk and
height and number of stories (but not minimum lot size), such requirements may not be “more
restrictive than is required for the Principal Dwelling, or a Single-Family Residential Dwelling or
accessory structure in the Zoning District in which the Protected Use ADU is located, whichever
results in more permissive regulation...” 760 CMR 71.03 (3)(b)(2). Towns may also impose site
plan review of a Protected Use ADU, but the Regulations requires the site plan review to be clear
and objective and prohibits the site plan review authority from imposing terms or conditions that
“are unreasonable or inconsistent with an as-of-right process as defined in M.G.L. c. 40A, § 1A.”
760 CMR 71.03 (3)(b)(5).
We incorporate by reference our more extensive comments regarding these recent statutory
and regulatory changes related to ADUs in our decision to the Town of East Bridgewater, issued
on April 14, 2025 in Case # 11579.9 Against the backdrop of these statutory and regulatory
parameters regarding Protected Use ADUs, we review the zoning amendments adopted under
Articles 6 and 8.
requirements as provided in Section 71.03; (3) use and occupancy restrictions; (4) unit caps and density
limitations; or (5) a requirement that the Protected Use ADU be attached or detached to the Principal
Dwelling.
7 For example, a design standard that is not applied to a Single-Family Residential Dwelling in the Single
Family Residential Zoning District in which the Protected Use ADU is located or is so “restrictive,
excessively, burdensome, or arbitrary that it prohibits, renders infeasible, or unreasonably increases the
costs of the use or construction of a Protected Use ADU” would be deemed an unreasonable regulation.
See 760 CMR 71.03 (3)(b).
8 Section 71.03 (3)(a) provides that while a town may reasonably regulate and restrict Protected Use ADUs,
a restriction or regulation imposed “shall be unreasonable” if the regulation or restriction, when applicable
to a Protected Use ADU: (1) does not serve a legitimate Municipal interest sought to be achieved by local
Zoning; (2) serves a legitimate Municipal interest sought to be achieved by local Zoning but its application
to a Protected Use ADU does not rationally relate to the legitimate Municipal interest; or (3) serves a
legitimate Municipal interest sought to be achieved by local Zoning and its application to a Protected Use
ADU rationally relates to the interest, but compliance with the regulation or restriction will: (a) result in
complete nullification of the use or development of a Protected Use ADU; (b) impose excessive costs on
the use or development of a Protected Use ADU without significantly advancing the Municipality’s
legitimate interest; or (c) substantially diminish or interfere with the use or development of a Protected Use
ADU without appreciably advancing the Municipality’s legitimate interest.
9 This decision, as well as other recent ADU decisions, can be found on the Municipal Law Unit’s website
at www.mass.gov/ago/munilaw (decision look up link) and then search by the topic pull down menu for the
topic “ADUS.”
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VI. We Disapprove Certain Text Adopted under Articles 6 and 8 Because It
Conflicts with G.L. c. 40A, § 3 and the Regulations
A- Article 6 - References to a “Single-Family” Dwelling
Under Article 6 the Town added a new definition for “Accessory Dwelling Unit” as follows
(with emphasis added):
Accessory Dwelling Unit: A secondary dwelling unit, but not a mobile home,
located either within or on the same lot as a detached single-family dwelling. The
accessory dwelling unit shall be subordinate in size to the principal dwelling unit
and separated from it in a manner that maintains the appearance of the structure as
a single-family house.
We disapprove and delete the words “single-family” shown above in bold and underline
that limits ADUs as accessory to a single-family dwelling because limiting ADUs to a single
family dwelling conflicts with G.L. c. 40A, § 3 and the Regulations that allow ADUs as-of-right
on the same lot as any type of “Principal Dwelling,” as explained below. See West Street
Associates, LLC v. Planning Board of Mansfield, 448 Mass 319, 324 (2021) (citing with approval
trial judge’s ruling that “By limiting medical marijuana facilities to nonprofit entities, the bylaw[,]
while not prohibiting] those facilities, does restrict them in a ways that the [S]tate explicitly
determined they should not be limited” and “[accordingly, the town's bylaw is preempted by State
law to the extent it requires all medical marijuana dispensaries to be nonprofit organizations.”)
General Laws Chapter 40A, Section 3 and the Regulations allow Protected Use ADUs as-
of-right on the same lot as any type of “Principal Dwelling,” not just a single-family dwelling. See
760 CMR § 71.02’s definitions of “Accessory Dwelling Unit (ADU)” (defining an ADU as “[a]
self-contained housing unit, inclusive of sleeping, cooking, and sanitary facilities on the same Lot
as a Principal Dwelling ...”) and “Protected Use ADU” (defining a “Protected Use ADU” as “[a]n
attached or detached ADU that is located, or is proposed to be located, on a Lot in a Single-Family
Residential Zoning District.”). The Regulations define “Principal Dwelling” as a structure that
contains at least one dwelling unit as follows (with emphasis added):
A structure, regardless of whether it, or the Lot it is situated on, conforms to Zoning,
including use requirements and dimensional requirements, such as setbacks, bulk,
and height, that contains at least one Dwelling Unit and is, or will be, located on
the same Lot as a Protected Use ADU.
The Regulations’ definition of “Principal Dwelling” contemplates Protected Use ADUs on
lots that include more than one dwelling unit. For example, Protected Use ADUs are allowed on
lots containing a two-family dwelling or a multi-family dwelling. Therefore, the above quoted
provisions that state that ADUs are allowed only on lots with a “single-family” dwelling conflict
with G.L. c. 40A, § 3 and the Regulations. For this reason, we disapprove the words “single
family” as shown above in bold and underline.
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Finally, we highlight for the Town’s consideration that Section 11.0’s definition of
“Accessory Dwelling Unit,” does not match the definition for “Accessory Dwelling Unit,” in G.L.
c. 40A, § 1A, as quoted in full above in Section III of this decision. We encourage the Town to
consult with Town Counsel regarding a future amendment to address this issue. In the interim, the
Town cannot apply the by-law’s definition of “Accessory Dwelling Unit,” in a manner that
prohibits or restricts a Protected Use ADU, as defined in G.L. c. 40A, § 1 A, from being constructed
or used.10
B. Article 8
1. Section 8.1.2’s Requirement that ADUs are Allowed in a District
Where Single-Family Homes are Allowed As-of-Right
Section 8.1.2, “Limitations on Use,” allows ADUs as-of-right, but imposes restrictions on
their use, in relevant part as follows (with emphasis added):
One Accessory Dwelling Unit (ADU) shall be allowed as-of-right in all zoning
districts in which single-family homes are allowed as-of-right subject to the
following restrictions...
We disapprove and delete the text “as-of-right” because it conflicts with G.L. c. 40A, § 3
and the Regulations that do not limit Protected Use ADUs to only an “as-of-right” single-family
home in a single-family residential zoning district, as explained below.
General Laws Chapter 40A, Section 3 prohibits a zoning by-law from “prohibitfing],
unreasonably restricting] or requirefing] a special permit or other discretionary zoning approval
for the use of land or structures for a single accessory dwelling unit, or the rental thereof, in a
single-family residential zoning district...” (with emphasis added). The Regulations, 760 CMR
71.02, define the term “single-family residential zoning district” as follows, with emphasis added:
Any Zoning District where Single-family Residential Dwellings are a permitted or
an allowable use, including any Zoning District where Single-family Residential
Dwellings are allowed as-of-right or by Special Permit.
Because 760 CMR 71.02 allows a Protected Use ADU as-of-right in any “Single-family
Residential Zoning District,” and the Regulations define a “Single-family Residential Zoning
District” to include any zoning district where single-family residential dwellings are permitted
either by-right or by special permit, the provision in Section 8.1.2 that limits an as-of-right ADU
to only those zoning districts where a single-family home is allowed “as-of-right” conflicts with
the Regulations. We therefore disapprove and delete the text shown above in bold and underline.
10 With regards to the portion of the definition of “Accessory Dwelling Unit,” that prohibits a mobile home
as an ADU, we offer additional comments regarding this restriction for the Town’s consideration below in
Section VII (A).
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2. Section 8.1.2's Minimum Lot Size and Setback Requirements
Section 8.1.2 imposes a minimum lot size requirement and setback requirement for an
ADU as follows (with emphasis added):
B. The Lot contains a minimum of 5,000 square feet of area;
D. The ADU is subject to the same dimensional setbacks as the primary
residence, as provided in Section 4.0 of this Zoning By-law;
We disapprove and delete the text shown above in bold and underline as explained below.
First, we disapprove Section 8.1.2 (B)’s minimum lot size requirement because it conflicts
with the Regulations, 760 CMR 71.03 (3), “Unreasonable Regulation,” Subsection (b)(2),
“Dimensional Standards” that prohibits the imposition of a minimum lot size requirement in
relevant part as follows:11
Any requirement concerning dimensional standards.. .that are more restrictive than
is required for the Principal Dwelling, or a Single-family Residential Dwelling or
an accessory structure in the Zoning District in which the Protected Use ADU is
located, whichever results in more permissive regulation, provided that a
Municipality may not require a minimum Lot size for a Protected Use ADU,
Because the Regulations, 760 CMR 71.03 (3)(b)(2), prohibit a Town from requiring a
minimum lot size for a Protected Use ADU, Section 8.1.2 (B) conflicts with the Regulations and
we therefore disapprove the text shown above in bold and underline.
Second, we disapprove and delete the portion of Section 8.1.2 (D), as shown above in bold
and underline, that requires the ADU to have the same dimensional setbacks as “the primary
residence” because this requirement conflicts with 760 CMR 71.03 (3), as quoted above, that
prohibits the Town from imposing a dimensional requirement on an ADU that is more restrictive
than that required for the Principal Dwelling, or a Single-family Residential Dwelling or an
accessory structure in the Zoning District in which the Protected Use ADU is located and requires
the more permissive dimensional requirement to be applied. Because Section 8.1.2 (D) would
impose a setback requirement that is the same as that for the primary residence, as opposed to that
which is the more permissive regulation as between the Principal Dwelling, or a Single-family
Residential Dwelling or an accessory structure in the Zoning District in which the Protected Use
ADU is located, this portion of Section 8.1.2 (D) conflicts with the Regulations and we therefore
disapprove it as shown above in bold and underline.
11 The Regulations, 760 CMR 71.02, define the term “Lot” as: “An area of land with definite boundaries that is used,
or available for use, as the site of a structure, or structures, regardless of whether the site conforms to the requirements
of Zoning.”
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3. Reference to “Single-Family ’’ Dwelling in Section 8.1.4
Section 8.1.4, “Exterior Appearance of a Dwelling with an ADU,” requires in relevant part
as follows, with emphasis added:
The ADU shall be designed so that the appearance of the structure remains that of
a single-family dwelling, subject further to the following requirements:
We disapprove and delete the portion of Section 8.1.4 that requires the ADU to be designed
such that the appearance of the structure remains that of a single-family dwelling because this
provision conflicts with G.L. c. 40A, § 3 and the Regulations that allow ADUs in principal
dwellings besides a “single-family” dwelling.
As discussed in Section VI (A) above, the Regulations’ definition of “Principal Dwelling”
contemplates Protected Use ADUs on lots that include more than one dwelling unit. For example,
Protected Use ADUs are allowed on lots containing a two-family dwelling or a multi-family
dwelling. Section 8.1.4’s requirement that an ADU to be designed “so that the appearance of the
structure remains that of a single-family dwelling” would be unachievable when the principal
dwelling is other than a single-family dwelling. Because this provision conflicts with G.L. c. 40A,
§ 3 and the Regulations, we disapprove and delete the text shown above in bold and underline.
4. Section 8.1.6’s Parking Requirements
Section 8.1.6, “Parking,” imposes parking requirements on ADUs as follows, with
emphasis added:
A. There shall be a minimum of one (1) off-street parking space per ADU in
addition to the parking spaces that are required by the underlying zoning district
for the single-family residence;
B. No additional parking spaces over and above that of the underlying
zoning district shall be required if the ADU is located within 0.5 miles from a
commuter rail station, subway station, ferry terminal, or bus station;
C. A single driveway shall serve both the single-family residential structure
and the ADU, provided that a detached ADU may have a separate parking area.
We disapprove and delete the parking provisions shown above in bold and underline. First,
the provision that mandates “a minimum of’ one off-street parking space conflicts with G.L. c.
40A, § 3 and the Regulations. General Laws Chapter 40A, Section 3 prohibits a municipality from
requiring more than one parking space when an ADU is located outside the 0.5-mile radius of a
transit station, as follows:
The use of land or structures for an accessory dwelling unit under this paragraph
shall not require owner occupancy of either the accessory dwelling unit or the
principal dwelling; provided, that not more than 1 additional parking space shall be
10Source page 12
required for an accessory dwelling unit; and provided further, that no additional
parking space shall be required for an accessory dwelling located not more than 0.5
miles from a commuter rail station, subway station, ferry terminal or bus station.
In addition, the Regulations, 760 CMR 71.03 (2) prohibit a Town from imposing any
prohibited Regulations on a Protected Use ADU, including the following:
(b) Minimum Parking Requirements. A requirement of, as applicable:
1. More than one additional on-street or off-street parking space for a
Protected Use ADU if all portions of its Lot are located outside a 0.5
mile radius of a Transit Station; or
2. Any additional on-street or off-street parking space for a Protected
Use ADU if any portion of its Lot is located within a 0.5 mile radius
of a Transit Station.
Because Section 8.1.6 (A) requires an ADUs to provide “a minimum of’ one additional
off-street parking space it conflicts with G.L. c. 40A, § 3 and 760 CMR 71.03 (2) (b), and we
therefore disapprove and delete the text as shown above in bold and underline. The Town is
authorized by the statute and the Regulations to require one additional parking space for a
Protected Use ADU that is not located within a 0.5-mile radius of a Transit Station. However, the
Town cannot, as it has done here, require an ADU to provide “a minimum of’ one additional
parking space because as written, that requirement would allow the Town to require more than one
parking space for an ADU or require a parking space for a lot with an ADU that is located within
a 0.5-mile radius of a transit station other than a commuter rail station. See West Street Associates,
LLC, 488 Mass, at 324. For this reason, we disapprove and delete the text shown above in bold
and underline.
We further disapprove the references in Section 8.1.6 (A) and (C) to “single-family,”
because, as discussed in more detail above in Section VI (A), a Protected Use ADU is not limited
to a single-family dwelling but instead is allowed on the same lot as any type of “Principal
Dwelling.” See 760 CMR § 71.02’s definitions of “Accessory Dwelling Unit (ADU)” and
“Protected Use ADU.” For this reason, we disapprove and delete the references to “single-family,”
in Section 8.1.6 (shown above in bold and underline) because they conflict with G.L. c. 40A, § 3
and the Regulations.
Finally, we disapprove and delete the text in Section 8.1.6 (B) (shown above in bold an
underline) that provides that an additional parking space “over and above that of the underlying
zoning district” is not required if the ADU is located within 0.5-mile radius of a transit station,
because it conflicts with G.L. c. 40A, § 3 and the Regulations that prohibit a town from requiring
an additional parking space for an ADU located within a 0.5-mile radius of a transit station. The
Regulations, 760 CMR 71.02, define “Transit Station” as: “[a] Subway Station, Commuter Rail
Station, Ferry Terminal, or Bus Station.” The regulations further define each of these terms,
including the term “Bus Station,” defined as: “[a] location serving as a point of embarkation for
any bus operated by a Transit Authority.” The requirement that an ADU within a 0.5-mile radius
11Source page 13
must still provide parking spaces required by the underlying zoning district imposes a parking
requirement on a Protected Use ADU that exceeds that allowed under the statute and the
Regulations. For this reason, we disapprove the text in Section 8.1.6 (B) shown above in bold and
underline.
VII. The Remaining Approved ADU Requirements Must be Applied Consistent with G.L.
c. 40A, § 3 and the Regulations
We offer comments for the Town’s consideration regarding certain approved provisions
adopted under Articles 6 and 8 to ensure that the Town applies these provisions consistent with
G.L. c. 40A, § 3 and the Regulations.
A. Article 6 - Mobile Home Prohibition
Under Article 6 the Town added a new definition of “Accessory Dwelling Unit,” that
prohibits an ADU from being a mobile home, in relevant part as follows with emphasis added:
“Accessory Dwelling Unit: A secondary dwelling unit, but not a mobile home, located either
within or on the same lot...” Neither Section 11.0, “Definitions,” or elsewhere in the Town’s
existing zoning by-laws does the Town define the term “mobile home.” “Mobile homes” are now
generally referred to as “manufactured home.” See The Attorney General’s Guide to Manufactured
Housing Community Law, pg. 6 at https://www.mass.gov/doc/attorney-generals-guide-to-
manufactured-housing-may-2024/download (stating “Many manufactured housing residents have
found that manufactured homes (sometimes called “mobile homes”) offer the benefits of
traditional site-built housing at a much lower cost.”) The term “manufactured home” is defined in
G.L. c. 140, § 32Q as follows:
As used in sections thirty-two A to thirty-two P, inclusive, the words “manufactured
home” shall mean a structure, built in conformance to the National Manufactured
Home Construction and Safety Standards which is transportable in one or more
sections, which in the traveling mode, is eight body feet or more in width or forty
body feet or more in length, or, when erected on site, is three hundred twenty or
more square feet, and which is built on a permanent chassis and designed to be used
as a dwelling unit with or without a permanent foundation when connected to the
required utilities, and includes the plumbing, heating, air conditioning, and
electrical systems contained therein.
The Regulations neither define or refer to a “mobile home” or “manufactured home.”
Instead, the Regulations refer only to a “Modular Dwelling Unit,” defined as follows:
A pre-designed Dwelling Unit assembled and equipped with internal plumbing,
electrical or similar systems prior to movement to the site where such Dwelling
Unit is affixed to a foundation and connected to internal utilities; or any portable
structure with walls, a floor, and a room, designed or used as a Dwelling Unit,
transportable in one or more sections and affixed to a foundation an connected to
external utilities.
12Source page 14
With regards to a “Modular Dwelling Unit,” the Regulations 760 CMR 71.03 (3)(b)(7)
provide that “[a]ny requirement that prohibits, regulates or restricts a Modular Dwelling Unit from
being used as a Protected Use ADU that is more restrictive than the Building Code” is an
unreasonable regulation. We have considered whether the by-law’s restriction on a mobile home
being used as ADU conflicts with the Regulations. Under our standard of review and based on the
above definitions, we cannot conclude that a “mobile home” is the same as a “Modular Dwelling
Unit.” Therefore, we cannot conclude that the by-law’s prohibition on a mobile home being used
as an ADU conflicts with the Regulations.12 However, we also cannot predict with any certainly
whether, if this provision is challenged, a Court on a full factual record, may conclude otherwise.
We therefore encourage the Town to consult with Town Counsel to ensure that the application of
this provision serves, and is rationally related to, a legitimate municipal interest and will not, as
applied, result in a nullification, impose an excessive cost or substantially diminish or interfere
with the use or development of a Protected Use ADU. See 760 CMR 71.03 (3)(a). If the Town
cannot satisfy this standard, the regulation may be deemed to be unreasonable.
B. Article 8
Under Article 8, the Town voted to amend its zoning by-laws by deleting Section 8.1,
“Accessory Apartments,” in its entirety and inserting a new Section 8.1, “Accessory Dwelling
Units,” that regulates ADUs.
1. Section 8.1.4’s Requirements on theADU’s Appearance
Section 8.1.4, “Exterior Appearance of a Dwelling with an ADU,” imposes requirements
related to the ADU’s design including that:
A. All stairways to the second or third stories shall be enclosed within the
exterior walls of the dwelling;
B. Any new, additional entrance to an existing dwelling shall be located on the
side or in the rear of the dwelling; and
C. Where there are two (2) or more existing entrances on the front faqade of a
dwelling, if modifications are made to any entrance, the result shall be that
one (1) appears to be the principal entrance and other entrances appear to
be secondary.
Based on our standard of review, we cannot conclude that these requirements are
unreasonable and therefore prohibited under 760 CMR 71.03, and for that reason we approve them.
However, if these requirements are used in a manner to prohibit or unreasonably restrict a Protected
Use ADU, such application would run afoul to the Dover amendment protections given to a
Protected Use ADU under G.L. c. 40A § 3 and the implementing Regulations. In addition, the
Town must ensure that the application of these requirements serve, and are rationally related to, a
12 For example, G.L. c. 140, § 32Q definition of “manufactured home” provides that it does not need to be
affixed to a permanent foundation; but the Regulations’ definition of “Modular Dwelling Unit” requires it
to be affixed to a foundation.
13Source page 15
legitimate municipal interest and will not, as applied, result in a nullification, impose an excessive
cost or substantially diminish or interfere with the use or development of a Protected Use ADU.
See 760 CMR 71.03 (3)(a). If the Town cannot satisfy this standard, the regulation may be deemed
to be unreasonable. The Town should consult with Town Counsel to ensure the proper application
of these provisions to a Protected Use ADU.
2. Section 8.1.5's Dimensional Requirements
Section 8.1.5, “Dimensional Requirements,” requires the ADU to comply with “all
applicable dimensional requirements in Section 4.0 of the Town of Canton Zoning By-laws.” We
have reviewed the Town’s existing zoning, Section 4.0, “Dimensional Requirements,” including
Section 4.1.4, “Table of Dimensional Requirements - Residence Districts,” and Section 4.1.5,
“Table of Dimensional Requirements -Nonresidential Districts” and note that these Tables impose
several types of dimensional requirements including minimum lot size and setback requirements.
Although we approve 8.1.5, the Town cannot apply these dimensional requirements to
impose any minimum lot size requirement on a Protected Use ADU because this application would
conflict with the Regulations. Specifically, 760 CMR 71.03 (3)(b)(2), prohibits a Town from
requiring a minimum lot size for a Protected Use ADU.13 We encourage the Town to consult with
Town Counsel about an amendment at a future Town Meeting that clearly states that Section 4.0’s
minimum lot size requirements are not applicable to an ADU. See also discussion above in Section
VI (B) (2). In the interim, the Town cannot apply any minimum lot size requirements in Section
4.1.4 or 4.1.5 (or elsewhere in the Town’s zoning by-laws) to a Protected Use ADU because such
an application would conflict with 760 CMR Section 71.03 (2).
In addition, in applying Section 8.1.25s requirements, we remind the Town that 760 CMR
71.03 (b)(2)(a) prohibits towns from imposing dimensional requirements, such as setbacks, lot
coverage, open space, bulk and height, and number of stories that are more restrictive than required
for the Principal Dwelling, Single-Family Dwelling (as defined in 760 CMR 71.02) or other
accessory structure in the zoning district where the Protected Use ADU is located, whichever is
more permissive. Sections 4.1.4 and 4.1.5 impose dimensional requirements, including lot width,
minimum non-wetland area, frontage, lot coverage, and setbacks based on the zoning district in
which the lot is located. The Town must ensure that these existing dimensional requirements, as
applied to a Protected Use ADU, are no more restrictive than those required for a Principal
Dwelling, Single Family Dwelling or other accessory structure (as defined in 760 CMR 71.02) in
the zoning district where the Protected Use ADU is located, whichever is more permissive.
Moreover, the Town must ensure that the application of these dimensional requirements
serve, and are rationally related to, a legitimate municipal interest and will not, as applied, result
in a nullification, impose an excessive cost or substantially diminish or interfere with the use or
development of a Protected Use ADU. See 760 CMR 71.03 (3)(a). If the Town cannot satisfy this
standard, the dimensional regulations may be deemed to be unreasonable as applied to a Protected
13 The Regulations, 760 CMR 71.02, define “Lot” as “[a]n area of land with definite boundaries that is used,
or available for use, as the site of a structure, or structures, regardless of whether the site conforms to
requirements of Zoning.”
14Source page 16
Use ADU. In addition, an important additional requirement because a Protected Use ADU is a
Dover Amendment protected use, is that the Town can only impose “reasonable regulations” on a
Protected Use ADU. If the by-law provisions, including the Town’s existing dimensional
requirements, are used in a manner to prohibit or unreasonably restrict a Protected Use ADU, such
application would run afoul of the Dover amendment protections given to a Protected Use ADU
under G.L. c. 40A § 3. The Town should consult with Town Counsel to ensure the proper
application of these provisions to a Protected Use ADU.
We strongly suggest that the Town discuss Section 8.1.5 with Town Counsel to ensure that
it is applied consistent with the protections given to ADUs under G.L. c. 40A, § 3 and the
Regulations. In addition, the Town may wish to discuss with Town Counsel whether Section 8.1.5
should be amended to specifically include text that Protected Use ADUs is not subject to minimum
lot size requirements (as required by the Regulations) and that Protected Use ADUs may only be
subject to “reasonable regulations” (under the test set forth in Section 760 CMR 71.03 (3) of the
Regulations) because they are a Dover Amendment protected use under G.L. c. 40A and because
the Regulations prohibit towns from unreasonably regulating Protected Use ADUs. Finally, we
encourage the Town to discuss with Town Counsel whether the dimensional requirements for
ADUs should be included in the Town’s ADU by-law, rather than the ADU by-law referencing
other sections of the Town’s existing zoning by-laws, to ensure that those utilizing the ADU by
law have clear information regarding any required dimensional standards.
VIII. Conclusion
We partially approve Articles 6 and 8, except for the following: (1) references to “single
family” dwelling in Sections 8.14; 8.16 (A) and (C) and 11.0; (2) Section 8.1.2 that limits an as-
of-right ADU only where a single-family homes are allowed as-of-right; (3) Section 8.1.2 (B) that
imposes a minimum lot size requirement for construction of an ADU; (4) a portion of Section 8.1.2
(D) that imposes a setback requirement that is the same setback requirement as the primary
residence; and (5) a portion of Section 8.1.6’s parking requirements, that we disapprove and delete
as shown in Section VI in bold and underline.
The Town should consult closely with Town Counsel when applying the remaining
approved ADU provisions to ensure that they are applied consistent with G.L. c. 40A, § 3 and 760
CMR 71.00. If the approved provisions in Articles 6 and 8 are used to deny a Protected Use ADU,
or otherwise applied in ways that constitute an unreasonable regulation in conflict with 760 CMR
71.03 (3), such application would violate G.L. c. 40A, § 3 and the Regulations. The Town should
consult with Town Counsel and EOHLC to ensure that the approved by-law provisions are applied
consistent with G.L. c. 40A, § 3 and the Regulations, as discussed herein.
Finally, we remind the Town of the requirements of 760 CMR 71.04, “Data Collection,”
that requires municipalities to maintain certain records, as follows:
Municipalities shall keep a record of each ADU permit applied for, approved,
denied, and issued a certificate of occupancy, with information about the address,
square footage, type (attached, detached, or internal), estimated value of
construction, and whether the unit required any variances or a Special Permit.
Municipalities shall make this record available to EOHLC upon request.
15Source page 17
The Town should consult with Town Counsel or EOHLC with any questions about
complying with Section 71.04.
Note: Pursuant to G.L. c. 40, § 32, neither general nor zoning by-laws take effect unless the Town
has first satisfied the posting/publishing requirements of that statute.
Very truly yours,
ANDREA JOY CAMPBELL
ATTORNEY GENERAL
By: Nicole B. Caprioli
Assistant Attorney General
Deputy Director, Municipal Law Unit
10 Mechanic Street, Suite 301
Worcester, MA 01608
(774)214-4418
cc: Town Counsels Paul DeRensis and John Richard Hucksam
16Source page 18
ARTICLE 6 AS APPROVED BY ATTORNEY GENERAL AMEND ZONING BY-LAW SECTION 11.0 DEFINITIONS Accessory Apartment: A preexisting nonconforming dwelling unit created in a single-family dwelling by special permit granted by the zoning board of appeals and recorded at the Norfolk county registry of deeds prior to the adoption of An Act Relative to the Affordable Homes Act by the 193rd Massachusetts General Court on August 6, 2024. Accessory Structure: A subordinate structure located on the same lot as the main, or principal building or principal use, the use of which is customarily incidental to that of the principal building or use of the land. Lot Coverage: The portion of a lot, expressed as a percentage, that is occupied by buildings or structures, including accessory structures. Accessory Dwelling Unit: A secondary dwelling unit, but not a mobile home, located either within or on the same lot as a detached dwelling. The accessory dwelling unit shall be subordinate in size to the principal dwelling unit and separated from it in a manner that maintains the appearance of the structure as a house.
Source page 19
ARTICLE 8 AS APPROVED BY ATTORNEY GENERAL
AMEND ZONING BY-LAW SECTION 8.1
8.1 ACCESSORY DWELLING UNITS
8.1.1 Purpose.
1. To provide for housing options that reduce maintenance costs and are more affordable than
traditional single-family dwellings;
2. To provide a mechanism for development of a range of housing types that are responsive to
the sociocultural, health care, and recreational needs of residents;
3. To use energy, water, and materials more efficiently by increasing the housing supply through
concentrated, small-scale development;
4. To establish residential development standards and procedures that will support these
objectives; and
5. To facilitate housing production, diversity, and affordability in the Town's neighborhoods.
8.1.2 Limitations on Use. One Accessory Dwelling Unit (ADU) shall be allowed as-of-right in all
zoning districts in which single-family homes are allowed, subject to the following restrictions:
A. The ADU 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;
B. (Subsection B Disallowed by Attorney General);
C. The ADU is not larger in gross floor area than one half (1/2) the gross floor area of the
principal dwelling or 900 square feet, whichever is smaller;
D. The ADU is subject to dimensional setbacks, as provided in Section 4.0 of this Zoning
By-Law;
E. No ADU shall be constructed without issuance of a building permit by the Building
Commissioner; and
F. No use of an accessory apartment shall be permitted prior to issuance of a certificate
of occupancy by the Building Commissioner. A certificate of occupancy shall be issued
after the Building Commissioner determines that the accessory apartment as
constructed is in conformity with the approved plans and with the provisions of this
by-law.
8.1.3 Additional Accessory Dwelling Units. The Board of Appeals may issue a Special Permit for
additional ADUs over and above the first ADU allowed as-of-right on a lot.
8.1.4 Exterior Appearance of a Dwelling with an ADU. The ADU shall be designed so that the
appearance of the structure remains that of a dwelling, subject further to the following
requirements:
A. All stairways to second or third stories shall be enclosed within the exterior walls of
the dwelling;
B. Any new, additional entrance to an existing dwelling shall be located on the side or in
the rear of the dwelling; and
C. Where there are two (2) or more existing entrances on the front facade of a dwelling,
if modifications are made to any entrance, the result shall be that one (1) appears to
be the principal entrance and other entrances appear to be secondary.
8.1.5 Dimensional Requirements. Accessory Dwelling Units shall be subject to all applicable
dimensional requirements in Section 4.0 of the Town of Canton Zoning By-Laws.
8.1.6 Parking.
A. There shall be one (1) off-street parking space per ADU in addition to the parking
spaces that are required by the underlying zoning district;
B. No additional parking spaces shall be required if the ADU is located within 0.5 miles
from a commuter rail station, subway station, ferry terminal, or bus station;
C. A single driveway shall serve both the residential structure and the ADU, provided that
a detached ADU may have a separate parking area.
8.1.7 Severability. If any provision of this Section 8.1 Accessory Dwelling Units is found to be
invalid by a court of competent jurisdiction, the remainder of Section 8.1 shall not be affected but
shall remain in full force. The invalidity of any provision of this Section shall not affect the validity of
the remainder of the Town of Canton's Zoning By-Law.