Salem, MA
Salem, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 6/10 (10 is most accepting)
Last updated: 10.10.2024
Image source: Norwell Social
What You Need To Know
Salem, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. In Salem, one ADU per single-family home is allowed. Separately, owners who choose to rent their ADUs at or below 70% of the Fair Market Rent limit in Salem are eligible for a property tax exemption on their ADU.
Type of ADU Permit Required
ADUs in Salem do not require special permits, and can be built using a traditional building permit. For lots with two-five units, owners may apply for a special permit to build up to one ADU per unit. ADUs are not permitted on lots with over five units in Salem.
ADU Rules
An ADU can be maximum 900 square feet or half the Gross Floor Area of the main house; whichever is smaller.
The ADU and the main house must be owned by the same person(s).
Short-term rentals are prohibited.
No additional parking is required for an ADU.
ADUs may be attached or detached from the main house - if detached, they must be built at least 10 feet from the main house.
ADUs cannot be built in the front yard.
Detached ADUs can have a maximum height of 18 feet
Attached ADUs must maintain the architectural style of the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Exterior stairways need to be built on the side or rear of the ADU or main home.
Detached ADUs that are not owner occupied must have utilities on a separate service.
Resources:
https://library.municode.com/ma/salem/codes/zoning_ordinance?nodeId=S3.0USRE_3.2ACUS (See section 3.2.8)
Wayland, MA
Wayland, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10
Last updated: 11.14.2024
Image source: Town of Wayland Facebook
What You Need To Know
Wayland, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Wayland are outlined below.
Type of ADU Permit Required
ADUs in Wayland do not require special permits, and can be built using a traditional building permit.
ADU Rules
ADU Rules in Wayland:
Wayland allows one ADU per lot by right. To build more than one ADU, a special permit must be approved through the town.
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs may be attached or detached from the main house.
Short-term rentals are not allowed. The minimum rental time for ADUs is 31 days.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
If the ADU is within 0.5 miles of a transit station, no additional parking is needed. If it is further than 0.5 miles from a transit station, one off-street parking spot must be added.
In addition to the by right ADU, Wayland, via special permit, allows for an Affordable Accessory Dwelling Unit. For more information on this path, please see the link below.
Resources:
Norwell, MA
Norwell, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 6/10 (10 is most accepting)
Last updated: 10.10.2024
Image source: Norwell Social
What You Need To Know
ADUs are allowed by right in Norwell both detached and within existing homes. As the rules are written currently, if you want to build a detached ADU, you need to go through site plan review from the Planning Board.
Type of ADU Permit Required
ADUs require a building permit, but detached ADUs specifically require site plan review.
ADU Rules
Interior ADUs:
Entrance: Must have a separate entrance, either directly outside or via a shared corridor meeting building code requirements for egress.
Size: Maximum floor area is the lesser of 900 square feet or 50% of the principal dwelling's floor area.
Short-Term Rentals Prohibited: Restrictive covenant required, enforceable by the Town, prohibiting short-term rental use.
Bedroom Limit: Restricted to one bedroom.
Parking: Must have one dedicated parking space; principal dwelling must have at least two. Shared driveway usage required.
Appearance: Entrance and parking must maintain the single-family residential look; separate entrances should be less visible than the main entrance from the street.
Owner Occupancy: Either the principal dwelling or the ADU must be owner-occupied at all times.
Sewage Approval: Board of Health must approve sewage disposal according to Title 5 and other regulations.
Commercial Use: No commercial use allowed except for permitted home occupations.
Detached ADUs:
Entrance: Must have a separate entrance meeting state building code requirements.
Size: Maximum floor area is the lesser of 900 square feet or 50% of the principal dwelling's floor area. If part of a larger accessory structure, the ADU's designated space must meet this limit.
Short-Term Rentals Prohibited: Same restrictive covenant rules as interior ADUs.
Bedroom Limit: Restricted to one bedroom.
Parking: Requires one dedicated parking space; principal dwelling must have at least two. Shared driveway usage required.
Owner Occupancy: Either the principal dwelling or the detached ADU must be owner-occupied at all times.
Sewage Approval: Same sewage disposal approval as interior ADUs.
Design Standards: Must maintain the single-family residential appearance and adhere to setbacks. Detached ADUs cannot be located in front of the principal dwelling. Architectural design must align with the principal dwelling and requires site plan review.
Rental Use: Only one unit (either the principal dwelling or the ADU) can be rented at a time. Owners may reside in the ADU while renting out the principal dwelling.
Commercial Use: No commercial use allowed except for permitted home occupations.
Resources:
Burlington, MA
Burlington, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 5/10
Last updated: 11/3/2025
Image source: HDPT Physical Therapy
What You Need To Know
Burlington, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Burlington are outlined below.
Type of ADU Permit Required
ADUs in Burlington do not require special permits, and can be built using a traditional building permit. Residents are allowed to build one ADU per lot.
ADU Rules
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
Short-term rentals are not allowed.
Detached ADUs cannot be built closer to the road than the main house.
Both the main house and the ADU must be connected to public water and sewer systems.
Properties within ½ mile of a transit station do not require additional parking. Properties outside of that area require additional off-street parking (driveway or garage) for all cars owned by the occupants of the ADU.
If an ADU has a separate exterior entrance or is detached, the ADU must be accessible from a path or walkway.
Attached ADUs must maintain the architectural style of the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Exterior entrances for attached ADUs must be located on the side or back of the dwelling, so that the main house retains the appearance of having only one front door.
The main house and ADU must be owned by the same person(s).
Exterior staircases above the first floor are only allowed in special circumstances.
Resources:
Resources:
https://www.burlington.org/ArchiveCenter/ViewFile/Item/608 (See pages 135-137)
Hingham, MA
Hingham, MA Accessory Dwelling Unit (ADU) Rules
Last updated: 12/1/2025
Image source: See Plymouth
What You Need To Know
Hingham, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Hingham are outlined below.
Type of ADU Permit Required
ADUs in Hingham do not require special permits, and can be built using a traditional building permit. Residents are allowed to build one ADU per lot.
ADU Rules
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs may be attached or detached from the main house.
Short-term rentals are not allowed - the minimum rental term for an ADU in Hingham is 30 days.
Properties within ½ mile of a transit station do not require additional parking. Properties outside of that area require one additional off-street parking spot.
Attached ADUs must maintain the architectural style of the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Exterior entrances must be on the side or back of the main house.
Exterior staircases above the first floor are only allowed on the back of an ADU, and only under special circumstances.
The main house and ADU must be owned by the same person(s).
Resources:
https://www.hingham-ma.gov/DocumentCenter/View/25969/2025-Hingham-Zoning-By-Law_Clean?bidId= (See pages 136-138 of PDF)
Kingston, MA
Kingston, MA Accessory Dwelling Unit (ADU) Rules
Last updated: 12/05/2025
Image source: See Plymouth
What You Need To Know
Kingston, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Kingston are outlined below.
Type of ADU Permit Required
ADUs in Kingston do not require special permits, and can be built using a traditional building permit. Residents are allowed to build one ADU per lot.
The rules below are for building a by right ADU - there is also another type of ADU that can be built using a special permit. The rules and pathway for those ADUs are in most cases more complex. They can be found in the link in the resources section at the bottom of this page.
ADU Rules in Kingston:
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs may be attached or detached from the main house.
Short-term rentals are not allowed.
Properties within ½ mile of a transit station do not require additional parking. Properties outside of that area require one additional off-street parking spot for the ADU.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Resources:
https://www.kingstonma.gov/DocumentCenter/View/5817/2025-Annual-Town-Meeting-Warrant?bidId=
(See pages 27-31)
Wellesley, MA
Wellesley, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 6/10
Last updated: 10.29.2024
Image source: Town of Wellesley Facebook
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADU rules in Wellesley are pretty relaxed but still do not conform to the new Affordable Homes Act because of the permits needed and approval from the Planning Department.
Type of ADU Permit Required
ADUs require a building permit from the Inspector of Buildings and an annual certificate from the Planning Department.
ADU Rules
ADUs must match the principal dwelling’s style, including siding, roof pitch, trim, windows, and doors.
Exterior ADU doors cannot face public streets or private ways unless in pre-existing detached structures.
Exterior staircases must be hidden from public view and complement the main dwelling.
ADU construction must not exceed the principal dwelling’s height before ADU construction.
Detached ADUs are allowed only in the rear or side yard or in pre-existing buildings.
ADU size: minimum of 250 sq ft, maximum of 900 sq ft or 50% of the main dwelling’s gross area.
ADU must meet all applicable area and yard regulations.
Operational Requirements:
ADU owners must file a notice with the Registry of Deeds.
Owners must reside on the property for at least 184 days per year and cannot lease the owner unit when absent.
Minimum lease term for the non-owner-occupied unit is 30 days.
No product pickups or deliveries beyond typical residential activities.
ADUs cannot be used for a home business.
Resources:
https://wellesleyma.gov/DocumentCenter/View/30044/Section-513-Accessory-Dwelling-Units
Stoneham, MA
Stoneham, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10
Last updated: 10.29.2024
Image source: Town of Stoneham
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
A single ADU is allowed with a permit on single-family home properties, must share a wall with the main structure and can not exceed 750 SF. Permits are not transferrable to new owners outside of the family.
Type of ADU Permit Required
ADUs require a special permit.
ADU Rules
Permit Filing: A Special Permit is required, filed with the Registry of Deeds, and can be amended or rescinded if ownership or conditions change.
Automatic Reversion: If ownership changes outside of the family, the property reverts to single-family use unless a new permit is applied for.
Size and Structure: The ADU cannot exceed 750 square feet and must share at least 75% of a wall with the main dwelling; utilities must be single-metered.
Parking: One additional parking space is required for the ADU, in addition to two spaces for the primary residence.
Occupancy Limit: ADU occupancy is limited to two people and cannot be used for commercial purposes.
Deed Restriction: A deed restriction confirming owner occupancy must be filed, and a Certificate of Occupancy requires proof of the permit’s recording.
Single Ownership: The main and accessory dwellings must be under the same ownership and cannot be separated. Only one ADU is permitted per lot.
Resources:
https://www.stoneham-ma.gov/DocumentCenter/View/1223/Ch15-Zoning-Part-1
Reading, MA
Reading, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 5/10
Last updated: 10.29.2024
Image source: Reading Recap
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
A single ADU is allowed with a permit on single-family home properties. The ADU size cannot exceed one third of the residence and must maintain a single family appearance. Occupants limited to three.
Type of ADU Permit Required
ADUs require a special permit.
ADU Rules
An Accessory Apartment must not exceed the lesser of 1,000 square feet or one-third of the gross floor area of the primary residence, excluding garages, unfinished basements, sheds, or other accessory structures.
At least one owner must reside in either the Principal Dwelling or Accessory Apartment on the property.
The Accessory Apartment should maintain the single-family appearance of the property; new entries must be on the side or rear, and stairways to upper-level apartments should be enclosed within the building.
All motor vehicles associated with the Accessory Apartment must be parked off the street in a driveway or garage, without compromising the neighborhood’s single-family character.
Both the Principal Dwelling and Accessory Apartment must be connected to public water and sewer systems.
The apartment is limited to two bedrooms and a maximum of three occupants.
For detached structures built before 1910 or listed in the Historical Inventory, any exterior alterations should preserve the structure’s historical features, with limited footprint expansion (up to 10%).
A Detached Accessory Apartment cannot be located in the front yard or any area between the Principal Dwelling and a right-of-way, unless an existing structure in that area is converted.
Any Special Permit issued must ensure that the Accessory Apartment maintains the neighborhood's character and complements the Principal Dwelling.
Resources:
https://www.readingma.gov/DocumentCenter/View/2242/Zoning-Bylaw-PDF - page 38
Gloucester, MA
Gloucester, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 7/10 (10 is most accepting)
Last updated: 9.19.2024
Image source: City of Gloucester
What You Need To Know
ADUs are permitted within an existing single family home, attached, and detached in Gloucester.
Type of ADU Permit Required
ADUs that conform to the rules listed below require a building permit through the building inspector. Special permits may be granted through the zoning board of appeals if the requirements cannot be met.
ADU Rules
The owner(s) of the single-family dwelling in which the accessory dwelling unit is created must continue to occupy one of the units as their residence, except for bona fide temporary absences.
Where the ADU or the principal dwelling is occupied as a rental unit, the minimum occupancy or rental term shall be 30 days. No ADU shall be use for boarding or lodging purposes or used as a rental unit on a weekly or daily basis.
There shall be one off-street parking space for the ADU in addition to off- street parking spaces required for the principal dwelling. The parking space shall be constructed of materials consistent with the existing driveway and shall have vehicular access to the driveway. No parking shall be located between the front building line of the principal dwelling and the front lot line except in the existing driveway.
Where the driveway is located within 10 feet of the side lot line, at least four feet of the driveway side yard, measured from the side lot line, shall be a landscaped buffer zone within which parking shall be prohibited. The landscape buffer zone shall be sufficient to screen the parking from the abutting property
There shall not be more than one ADU on a lot. ADUs shall not be eligible for zoning dimensional variances proposing to increase the allowable number of ADUs on a lot. No ADU shall be separated from the principal dwelling through a condominium or cooperative conversion process or be held in separate ownership from the principal dwelling unit on the lot.
The construction of any ADU shall conform with the State Building Code and Title V of the State Sanitary Code, and shall be lawful under all other provisions of applicable health, building, zoning and other local laws and regulations.
The Planning Board shall have authority to adopt an ADU guidance document providing interpretation and guidelines to administer this Section 5.24.
For Attached ADUs
The ADU shall be located entirely inside the single-family structure, except as provided for in 5.24.4(c).
The accessory dwelling unit shall be designed to maintain the appearance of a single-family dwelling, subject to the following requirements.
The accessory dwelling unit shall be designed to maintain the appearance of a single-family dwelling, subject to the following requirements.
All stairways to an ADU above the first floor shall be enclosed within the exterior walls of the single-family structure or on the rear of the structure if constructed on an outer wall.
Where two or more entrances exist on the front facade of the single-family dwelling, one entrance shall appear to be the principal entrance and other entrances shall appear to be secondary. In the alternative the ADU may be accessed by a side or rear entry.
Exterior alterations are permitted provided they are in keeping with the architectural integrity of the structure, including, but not limited to, the following considerations:
The exterior finish material should be the same or visually consistent in type, size, and placement, as the exterior finish material of the remainder of the building;
Trim should be consistent in type, size, and location as the trim used on the remainder of the building;
Windows should be consistent with those of the remainder of the building in proportion and orientation;
Exterior staircases should be designed to minimize visual intrusion and be complementary to the existing building.
For Detached ADUs
A Detached ADU shall be maximum of 900 square feet or 50 percent of the total habitable space of the principal dwelling, whichever is less.
Alterations to an existing accessory structure or the creation of a new accessory structure for a Detached ADU are permitted provided they are in keeping with the architectural integrity of the existing principal dwelling on the lot and the residential character of the neighborhood. The exterior finish material should be the same or visually compatible in type, size, and placement, as the exterior finish material of the principal dwelling unit on the site.
For new construction of a Detached ADU, the building shall comply with the district's minimum setback requirements for accessory structures. The maximum height of the building shall be:
20 feet if the structure meets the normal accessory building setbacks, or
24 feet if the structure meets the normal principal dwelling setbacks.
Resources:
https://library.municode.com/ma/gloucester/codes/zoning_ordinance?nodeId=SVSPRE_5.24ACDWUNAD
Dunstable, MA
Dunstable, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 9.13.2024
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
Dunstable requires homeowners to jump through a number of hoops in order to build an ADU. If you have questions about the rules, please contact us. We would be happy to help!
Type of ADU Permit Required
A special permit is required through the zoning board of appeals.
ADU Rules
Except as otherwise provided in these Zoning Bylaws, not more than one accessory dwelling unit may be established on a lot [Amended 5/15/21]. The accessory dwelling unit shall not exceed 35% of the gross living space of the existing or expanded principal structure or 1,200 square feet, whichever is greater, and have no more than two bedrooms. The expansion of an existing structure to accommodate an accessory apartment shall not increase the gross floor space of the existing structure more than 15%.
The accessory dwelling unit may be located in the principal structure or in a detached accessory structure; provided, however, that an accessory dwelling unit may be located in such detached accessory structure only where such detached accessory structure has been in existence for at least ten (10) years. The burden shall be upon the applicant to demonstrate compliance with this subsection.
An accessory apartment shall be a complete dwelling unit with a separate entry, kitchen facilities, at least one bedroom, and a bathroom with sink, toilet and bathing facilities.
The external appearance of the structure in which the accessory dwelling unit is to be located shall not be significantly altered from the appearance of a single family structure or other structure ordinarily used and included in the context of single family dwellings, in accordance with the following:
The expansion of an existing structure to accommodate an accessory apartment shall not increase the gross floor space of the existing structure more than 15%.;
Any stairways or access and egress alterations serving the accessory dwelling unit shall be enclosed, screened, or located so that visibility from public ways is minimized;
Sufficient and appropriate space for at least one (1) additional parking space shall be provided by the owner to serve the accessory dwelling unit. Said parking space shall be constructed of materials consistent with the existing driveway and shall have vehicular access to the driveway;
All construction and/or renovation shall be performed in accordance with the applicable requirements of the State Building Code.
Prior to the conclusion of a Site Plan Review the owner must provide certification, by affidavit, that one of the two dwelling units shall be occupied by the owner of the property as his/her primary residence at least six months in any calendar year. In addition, such owner shall occupy such dwelling unit as his or her primary residence as a condition of the validity of the Special Permit. The owner must also own the entire lot, any structures thereon, and both dwellings.
The initial term and subsequent extensions of a special permit for an accessory dwelling unit shall terminate upon transfer of the ownership of the premises or when the owner no longer occupies the premises as his or her residence in accordance with Section (c) i above. Upon sale or transfer of the property to a new owner, the new owner must submit an affidavit to the Building Inspector of their intention to use one of the dwellings as their primary residence. A subsequent special permit may be granted after certification by affidavit is made by the applicant to the Board of Appeals that the accessory dwelling unit has not been extended, enlarged, or altered to increase its original dimensions, as defined in the initial special permit application.
Use and occupancy of any accessory apartment other than is authorized herein shall be grounds for revocation of any permit granted under this section.
Special Permits for an accessory dwelling unit may be issued by the Board of Appeals upon a finding that the construction and occupancy of the additional dwelling unit complies with foregoing provisions and will not be detrimental to the neighborhood in which the lot is located.
Nothing in this subsection 6.2.1 shall be construed to change or reduce any dimensional or area requirements of this Zoning Bylaw relative to single family dwellings and accessory structures thereto or to allow any uses not otherwise permitted by this Zoning Bylaw, other than accessory apartments as allowed.”
Resources:
Sudbury, MA
Sudbury, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 9/10 (10 is most accepting)
Last updated: 9.11.2024
Source: Sudbury Chamber of Commerce
What You Need To Know
Sudbury, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Sudbury are outlined below.
Type of ADU Permit Required
ADUs in Sudbury can be built using a traditional building permit. They do not require a special permit.
ADU Rules
Sudbury allows one ADU per lot
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs may be attached or detached from the main house.
ADUs cannot be used as short-term rentals.
ADUs must maintain a similar architectural style to the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
If the ADU is within 0.5 miles of a transit station, no additional parking is needed. If it is further than 0.5 miles from a transit station, one off-street parking spot must be added.
The main house and ADU must be owned by the same person(s).
Exterior stairways need to be built on the side or rear of the ADU or main home.
Resources:
Winchester, MA
Winchester, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 11/17/2025
Source: Town of Winchester Facebook
What You Need To Know
Winchester, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Winchester are outlined below.
Type of ADU Permit Required
ADUs in Winchester do not require special permits, and can be built using a traditional building permit. Residents are allowed to build one ADU per single-family home or duplex.
ADU Rules
An ADU can be maximum 900 square feet or half the Gross Floor Area of the main house; whichever is smaller.
In the case of duplexes, the ADU can be 900 square feet or half the Gross Floor Area of the larger unit; whichever is smaller.
ADUs may be attached, detached, or built within the main house.
Short-term rentals are not allowed - the minimum rental term for ADUs in Winchester is 31 days.
The main house and ADU must be owned by the same person(s).
Properties within ½ mile of a transit station do not require additional parking. Properties outside of that area require additional off-street parking (driveway or garage). e
Construction of a new garage for an ADU requires a special permit with the town.
ADUs should maintain the architectural style of the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Exterior entrances for ADUs should be clearly secondary to the entry of the main house.
Exterior staircases above the first floor are only allowed within the home or on the side or back of the primary dwelling.
Resources:https://ecode360.com/42152935#42152939 (See Section 3.2.2)
Chelmsford, MA
Chelmsford, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 9.10.2024
Source: Town of Chelmsford Facebook
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
Currently, Chelmsford allows a form of an ADU that is referred to as a Limited Accessory Apartment (LAA). These can only be constructed within or attached to a single family dwelling.
Type of ADU Permit Required
To construct an ADU within an existing dwelling, a building permit through the building inspector is required. A special permit is required to build an ADU attached to the existing home.
ADU Rules
An LAA as defined in Chelmsford is a self-contained unit within an owner-occupied single-family dwelling, providing space for bathing, cooking, and sleeping, and used exclusively by extended family members. It does not convert the dwelling into a two-family unit.
The LAA must have separate ingress/egress that maintains the single-family appearance. New entrances should be at the side or rear, with enclosed staircases and internal doorways between the LAA and the main unit.
The LAA size is limited to 750 square feet, excluding stairs and common areas.
Adequate off-street parking required, consistent with neighborhood character. Utilities must be connected to town sewer, and separate metering is not required unless mandated by the State Building Code.
Only one LAA per lot and can have no more than two occupants.
LAAs must be used only by extended family. Use restrictions must be recorded in the Registry of Deeds and include provisions for owner-occupancy and notice to potential buyers.
The Building Inspector issues permits by right. Special permits are handled by the Zoning Board of Appeals, which also records restrictions in the Registry of Deeds.
Applicants must submit architectural plans, site plans, names of residents, and an executed use restriction.
Special permits are based on zoning bylaws. The Zoning Board of Appeals may allow deviations for accessibility features.
New owners must file applications and inspections will ensure compliance. Violations may result in permit lapses, fines, and required special permits for continued use.
Resources:
Millbury, MA
Millbury, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10 (10 is most accepting)
Last updated: 8.28.2024
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADUs are allowed within all Residential and Suburban Districts on lots that meet the zoning district dimensional requirements or on lots/in structures that are legally pre-existing nonconforming.
Type of ADU Permit Required
ADUs require a special permit.
ADU Rules
Only one ADU is allowed on a lot.
The appearance of a single-family home must be kept in.
Any new entrance to the ADU must be either on the side or rear of the home.
The gross floor area of an ADU cannot be greater than 800 square feet.
Two off-street parking spaces must be provided for the residents of the ADU.
For ADUs built on lots with pre-existing nonconforming single-family homes, the living area of the existing single-family home cannot be increased in total square footage or footprint altered.
The Zoning Board of Appeals may allow in some circumstances deviations from certain requirements to accommodate individuals living needs.
Resources:
Middleborough, MA
Middleborough, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10
Last updated: 8.28.2024
Image source: Wikipedia
What You Need To Know
Middleborough, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Middleborough are outlined below.
Type of ADU Permit Required
ADUs in Middleborough do not require special permits, and can be built using a traditional building permit.
ADU Rules in Middleborough:
Middleborough allows one ADU per building lot.
An ADU can be a maximum of 900 square feet.
ADUs can be attached or detached from the main house.
Short-term rentals are prohibited.
Detached ADUs cannot be taller than 2 stories, or 25 feet - whichever is shorter.
ADUs must maintain the architectural style of the main house to the extent possible.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
No multi-level exterior stairs are allowed as the main method of access to the ADU.
Detached ADUs cannot be built in the front yard.
Detached ADUs need to be built at least 10 feet from any other structure on the lot.
If the ADU is within 0.5 miles of a transit station, no additional parking is needed.
If it is further than 0.5 miles from a transit station, one off-street parking spot must be added.
If off-street parking is necessary, it must be in the side or back yard of the main house and use the existing driveway.
The water connection for the ADU must come from the main house.
ADUs must have a separate electric meter, located outside.
ADUs need a separate water shut off.
ADUs and the main house must remain in single ownership - a deed restriction recorded at the Registry of Deeds is required.
Propane is not allowed on a lot that has an existing gas connection (from MG&E) - we build all-electric homes, so this isn’t a problem!
Resources:
Fitchburg, MA
Fitchburg, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 7/10 (10 is most accepting)
Last updated: 8.28.2024
Source: City of Fitchburg
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADUs are allowed only within or attached with minimal impact to the existing single family home. ADUs are permitted in a limited number of zoning districts.
Type of ADU Permit Required
ADUs are allowed by right via a building permit in the Rural Residential (RR) and Residence A (RA), but in zoning district Residence B (RB) ADUs require a special permit.
ADU Rules
A plan from a registered land surveyor must be submitted to the building commissioner that includes the existing dwelling, the proposed location of the ADU, location of any septic system, and required parking.
The ADU must be occupied by the owner of the property except for a bona fide temporary absence.
This has to be certified by an affidavit.
Not more than one ADU is allowed per lot.
The ADU cannot be greater than 800 square feet of habitable floor space.
The ADU must be within the primary structure.
The external appearance of the existing dwelling cannot be significantly altered from the appearance of a single family home.
The ADU cannot result in an increase of more than 15% in the habitable and non-habitable floor area of the existing dwelling.
Any stairways must be within or screened in.
One additional parking space must be provided for the ADU
Special permits for ADUs are issued by the board of appeals only after the construction and occupancy of one is not detrimental to the neighborhood.
Resources:
Nantucket, MA
Nantucket, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 8/10 (10 is most accepting)
Last updated: 8.16.2024
Image source: Town & County of Nantucket
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
There is not a lot of information about ADUs in Nantucket. However, their ordinances indicate that they are allowed in all zoning districts except for one. Contact our team to determine what is available in your zoning district!
Type of ADU Permit Required
ADUs are permitted by right on Nantucket.
ADU Rules
ADUs must be located within an existing single-family home.
The appearance and use of a single-family home must be maintained with the addition of an ADU.
The gross floor area is limited to 800 square feet.
The ownership of the single-family home and the ADU must remain the same.
Either the ADU or single-family home must be occupied by the owner.
Resources:
https://www.nantucket-ma.gov/DocumentCenter/View/18728/Exhibit-2-B----Nantucket-Zoning-Relief-PDF
https://ecode360.com/14051042?highlight=accessory%20dwelling&searchId=4566888406095905#11471476
Pembroke, MA
Pembroke, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 8.15.2024
Source: Town of Pembroke
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
Currently, there are some hoops to jump through with ADUs in Pembroke. In addition to requiring a special permit, owners must sign a 15 year use restriction and agree to a maximum rent to be charged. ADUs must be rented to a person having an annual income of no more than 80% of the area median income. The Pembroke Housing Authority will monitor compliance with the ADU rules.
Type of ADU Permit Required
ADUs are allowed by special permit through the Zoning Board of Appeals in Pembroke.
ADU Rules
ADUs may be allowed on lots with at least 20,000 square feet of contiguous upland except for ADUs already in existence prior to the current ordinance.
The owner of the property must occupy the primary dwelling and rent the ADU.
The ADU cannot be larger than 800 square feet.
ADUs are limited to one bedroom and two occupants.
Two parking spaces must be provided for the ADU
An ADU must be attached to the existing single family home.
Resources:
Northborough, MA
Northborough, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 7/10 (10 is most accepting)
Last updated: 8.14.2024
Source: Town of Northborough
What You Need To Know
Northborough, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Northborough are outlined below.
Type of ADU Permit Required
ADUs are permitted by right in Northborough and require a building permit.
ADU Rules
ADU Rules in Northborough:
Northborough allows one ADU per building lot.
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
Short-term rentals are prohibited.
ADUs can be attached or detached from the main house.
Attached and detached ADUs must maintain the architectural style of the main house to the extent possible.
ADUs should be no taller than the main house.
ADUs must have a separate entrance from the main house - attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
When possible, a detached ADU must be built to the rear or side of the main house and 10 feet from other buildings on the lot.
Multi-level exterior staircases are not allowed on attached or detached ADUs.
One dedicated off-street parking spot must be added for the ADU.
Detached ADUs must have a separate water meter and dedicated water service from the main to the ADU.
When possible, the sewer service for a detached ADU should connect from the main house.
Any direct connections from the ADU to the public sewer must be reviewed and approved from the Department of Public Works.
The main house and ADU must be owned by the same person(s).
Resources:
https://www.town.northborough.ma.us/sites/g/files/vyhlif12221/f/uploads/warrant_articles_approved_at_2025_annual_town_meeting.pdf (See pages 1-2)