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:
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)
Hanover, MA
Hanover, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 10.29.2024
Image source: Wikipedia
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADUs currently are only allowed to be built for families to live closer to one another. Also, ADUs can only be created within an existing single family home.
Type of ADU Permit Required
A special permit is needed and the owner(s) must file a Declaration of Covenants at the Plymouth County Registry of Deeds stating that the use of the ADU shall be restricted to relatives of the owner.
ADU Rules
Definition and Permitting: ADUs must be self-contained housing within a single-family dwelling (not in accessory structures) and require a special permit from the Zoning Board of Appeals.
Occupant Requirement: ADUs are designated for individuals related to the primary owner-occupant by blood, marriage, or adoption.
Limitations on Units: Only one ADU is allowed per dwelling and per residential lot.
Owner Occupancy: The owner must occupy one of the units as their primary residence, with exceptions for temporary absences.
Exterior Access: New exterior stairs for the ADU must be located on the side or rear, unless otherwise required by building codes.
Parking: Off-street parking must be provided for both owner-occupants and tenants; specific requirements are determined by the Zoning Board of Appeals.
Size Limits: ADU size is capped at 33% of the gross area of the primary residence (or 800 square feet, whichever is smaller).
Bedroom Limit: ADUs may have a maximum of two bedrooms.
Code Compliance: ADUs must meet State Building Code, State Sanitary Code, and local bylaws.
Familial Affidavit: ADU applications must include an affidavit confirming the familial relationship between occupants and owners.
Annual Certification: Owners must re-certify occupancy and family status with the Building Commissioner yearly and notify of tenant changes within 30 days.
Recorded Declaration: Owners must file a Declaration of Covenants with the Plymouth County Registry, restricting ADU use to relatives of the property owner.
Existing ADUs: ADUs existing before the bylaw must comply with the State Building Code; each case is reviewed individually.
Administration: The Building Commissioner oversees administration, issues permits, and enforces compliance. No ADU may be occupied without a certificate of occupancy.
Continuous Use: Permits for construction or special use must adhere to subsequent bylaw amendments unless construction begins within six months.
Documentation Requirement: ADUs without proper documentation may incur fines as per Section 12.500 of the Hanover Zoning Bylaw.
Sale Restriction: ADUs cannot be sold separately from the principal dwelling.
Resources:
Fairhaven, MA
Fairhaven, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10 (10 is most accepting)
Last updated: 9.19.2024
Image source: Fairhaven Visitors Center Facebook
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADUs are only allowed by converting an existing space within a single-family dwelling.
Type of ADU Permit Required
ADUs require a special permit in Fairhaven.
ADU Rules
Dwelling conversions shall not be allowed unless the lot meets the minimum lot size in § 198-18 or 22,500 square feet, whichever is greater.
Units created through dwelling conversions shall not be less than 1,000 square feet, not including areas of the basement, attic or garage.
The applicant shall illustrate to the Planning Board that the requirements of the State Building Code are met.
Site requirements.
No expansion to the existing structure.
Parking shall be as provided for in § 198-27B(1).
No portion of the basement, attic or garage may be used for dwelling purposes.
Use of an existing on-site septic system to service proposed units shall be permitted only upon approval of the Board of Health.
Resources:
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
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
Duxbury, MA
Duxbury, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10 (10 is most accepting)
Last updated: 8.14.2024
Source: See Plymouth
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
Duxbury allows ADUs only within existing single family homes.
Type of ADU Permit Required
ADUs are permitted under special permit in Duxbury. There are a number of hoops to jump through as the process is laid out in Duxbury’s zoning ordinance including approval from the Board of Appeals. If you’re interested in learning more about this process, please contact us.
ADU Rules
ADUs cannot be greater than 850 sq ft in area.
ADUs are only allowed within the existing dwelling and no alterations to the existing footprint can be made.
ADUs cannot be constructed on lots less than 20,000 square feet.
At least one additional parking space must be provided to serve the ADU.
The owner must reside in either the ADU or the primary dwelling.
The primary home must be at least 10 years old at the time of the special permit application, and the ADU must be built within a year of the date of the special permit application.
Resources:
https://www.town.duxbury.ma.us/zoning-board-appeals/pages/zoning-bylaws - Page 55-56
Marshfield, MA
Marshfield, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 4/10 (10 is most accepting)
Last updated: 8.14.2024
Image source: WATD News
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
ADUs are allowed via special permit in the R-1, R-2, R-3, B-1, and B-2 districts through the Board of Appeals. If you’d like help determining what is possible on your property, please reach out to our team!
Type of ADU Permit Required
ADUs are permitted through the Board of Appeals via a special permit.
ADU Rules
ADUs are limited to 40% of the total living area of the single-family dwelling and limited to one bedroom.
Only one ADU is allowed per lot.
ADUs are only allowed within existing single family dwellings currently.
ADUs must be designed so that the appearance of a single family home is maintained.
There are lot size requirements for specific districts:
For properties in B-1 and R-3 the lot size minimum is 10,000 square feet.
For properties in B-2 and R-2 the lot size minimum is 20,000 square feet.
For properties in R-1 the lot size minimum is 40,000 square feet.
One additional parking space must be provided for the ADU.
The ADU and the existing single family home must remain in common ownership.
If the property is sold, a new special permit must be applied for.
Each year, the owner of the property must recertify that the home is their primary residence.
Resources:
Plymouth, MA
Plymouth, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 9/10 (10 is most accepting)
Last updated: 8.14.2024
Source: Yankee Magazine
What You Need To Know
ADUs are allowed detached or attached to an existing home in all residential or mixed use zoning districts.
Type of ADU Permit Required
ADUs require first a zoning application that includes a site plan with setbacks and dimensions as well as a floor plan with a layout of the existing home and proposed ADU. After that a building permit is required.
ADU Rules
ADUs cannot be greater than 900 square feet of floor area.
This is in line with the Affordable Homes Act!
ADUs cannot be used as a short-term rental.
The ownership of the ADU cannot be split between the ADU and the single-family home.
Condos and Townhomes are not considered single-family homes in Plymouth; therefore, ADUs would not be permitted on lots with townhomes or condos.
The ADU must conform to the setbacks and general site requirements of the zoning district where it is built.
Only one ADU is permitted per lot.
Resources:
https://www.plymouth-ma.gov/DocumentCenter/View/6428/Update-Zoning-Bylaw-4-2024 page 5 of PDF
https://www.plymouth-ma.gov/1342/Accessory-Dwelling-Unit-ADU-Information
Sandwich, MA
Sandwich draws a distinction between “Accessory Dwelling Units” and “Accessory Apartments” and provide different rules for each.
Sandwich, MA Accessory Dwelling Unit (ADU) Rules
Last updated: 11.17.2025
What You Need to Know
Sandwich, 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 Sandwich are outlined below.
Type of ADU Permit Required
ADUs in Sandwich 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.
ADU Rules
Accessory Dwelling Units (ADUs)
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs can be attached, detached, or built within 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.
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.
Short-term rentals are not allowed. The minimum rental period for an ADU in Sandwich is twelve months.
The main house and ADU must be owned by the same person(s).
ADUs must have at least 1 dedicated parking space unless the ADU is within 0.5 miles from a transit station.
ADUs must remain in common ownership.
Resources: https://www.sandwichmass.org/DocumentCenter/View/10628/May-2025-Zoning-Bylaw (See pages 37-38)
Provincetown, MA
Provincetown allows property owners to build new attached and detached dwelling units by right in all zoning districts except S (Seashore) and M (Public Use) districts.
Provincetown, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10 (10 is most accepting)
Last updated: 6.6.2024
Image source: Frommers
What You Need To Know
ADU bylaws were recently updated in Provincetown. They now allow between two and four dwelling units on a single lot depending on your zoning district.
Type of ADU Permit Required
ADUs in Provincetown require a building permit, not a special permit.
ADU Rules
ADUs per lot are dependent on your residential district
Residential 1 Zoning District
No more than two dwelling units total
Residential 2 Zoning District
No more than three total dwelling units total
Residential 3, B, TCC, and GC Zoning Districts
No more than four dwelling units total
ADUs cannot be used for short term rentals. Must be rented for a period greater than 31 days.
Detached ADUs cannot be greater than 600 square feet.
40% of gross floor area if the ADU is located in the primary dwelling
Parking requirements do not apply to ADUs.
Resources:
Town of Provincetown Zoning By-laws- Page 29
https://www.provincetown-ma.gov/DocumentCenter/View/762/Zoning-By-Laws-PDF?bidId=
Mashpee, MA
Mashpee, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10 (10 is most accepting)
Last updated: 6.18.2024
Image source: Mashpee Commons
What You Need To Know
Accessory dwelling units are referred to as ADUs in Mashpee.
Type of ADU Permit Required
A building permit is required for an ADU.
ADU Rules
The property owner must reside in either the primary dwelling or accessory dwelling unit.
It is possible to rent either the primary dwelling or the ADU; however, both cannot be rented at the same time. Rental period may not be less than 30 consecutive days.
Conservations commission, historic, and wastewater treatment requirements must be complied with.
ADUs can be up to 900 square feet and cannot be less than 350 square feet.
ADUs can be within or attached to the existing dwelling or detached.
There cannot be greater than two bedrooms in an ADU.
The design of the ADU must be consistent with the existing dwelling.
One off-street parking space must be provided for the ADU.
ADUs cannot have their own driveway as new curb cuts are not permitted.
Resources:
Zoning Bylaws of the Town of Mashpee, MA- Article 4/§174-45.4 A/Page 80
https://www.mashpeema.gov/sites/g/files/vyhlif3426/f/uploads/2023_zoning_bylaws_0.pdf
Orleans, MA
Orleans currently has restrictive rules associated with adding an ADU to a single family lot. The town does not allow additions or new construction unless it will have a minimal impact on the existing footprint of the existing structures.
Orleans, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10 (10 is most accepting)
Last updated: 6.18.2024
Image source: Cape Cod Life
What You Need To Know
Orleans, like many other towns on Cape Cod, have made amendments to their zoning bylaws to combat the growing need in the area for affordable housing. Still, there remains a number of rules that must be complied with to build an ADU.
Type of ADU Permit Required
There are restrictions and guidelines, but ADUs are by right in Orleans and are approved by the building commissioner.
ADU Rules
The ADU cannot be greater than 800 square feet.
Additions cannot increase lot coverage by more than two percent of the lot area.
The lot must be at least 30,000 square feet of contiguous buildable upland.
One of the two units must be owner occupied year round.
The rental term must be at least 90 days.
Likely changes after vote in May:
The accessory dwelling shall contain no more 1,200 square feet of floor area.
The Board of Health must have documented to the Building Commissioner that sewage disposal will be satisfactorily provided for in accordance with the provisions of Title 5 and local Board of Health regulations, including provisions for an appropriate reserve area on the site.
There are no limitations on lot sizes.
The dwellings if leased shall be for periods of not less than ninety (90) days.
Resources:
Harwich, MA
Harwich, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10 (10 is most accepting)
Last Updated: 6.18.2024
Image source: Winstead Inn
What You Need To Know
In Harwich, ADUs are referred to as Accessory Apartments. These structures can be within, attached, or detached from the primary dwelling.
Type of ADU Permit Required
ADUs or ADUs require a special permit.
ADU Rules
Only one ADU is permitted per primary dwelling.
The ADU and primary dwelling must have the same owner.
Either the primary dwelling or the ADU may be rented, but only one unit can be rented at a time.
The rental period is limited to at least six consecutive months.
There is a limit of 1,000 square feet of gross floor area for ADUs.
The ADU may not have greater than two bedrooms
There must be one parking space available for the ADU.
The ADU must be designed in such a way that the property retains the characteristics of a single family home.
All applicable zoning ordinances, setbacks, and sewer/septic regulations must be met.
Resources:
Eastham, MA
Eastham loves ADUs and thinks they can help them ease their housing crisis. As with many towns in the Cape they allow all kinds of ADUs by right!
Eastham, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating:
10/10 (10 is most accepting)
What you need to know
Eastham loves ADUs and thinks they can help them ease their housing crisis. As with many towns in the Cape they allow all kinds of ADUs by right!
Type of permit is required?
ADUs are only allowed in the following districts:
By Right:
District A (Residential), E (Residential/limited commercial), G (Water Resource Protection), Core Commercial, Transition Commercial, Office Residential, Limited Commercial
By Special Permit:
District F (seashore)
Not Allowed:
District B (Marina), H (Wellhead Protection), and Trade Park
ADU rules in Eastham:
Only one ADU is permitted on a single family lot.
The unit must be a fully separate living area with its own kitchen, bathroom and egress.
The ADU shall be clearly subordinate to the primary home.
An ADU shall be designed so that the property continues to look like a single family lot and the privacy of abutting properties is maintained.
The lot does not require a minimum acreage of buildable upland.
The Accessory Dwelling Unit (ADU) shall contain no more than two bedrooms.
The maximum size for an ADU is 1200 square feet or fifty percent of the site coverage of the principal dwelling, whichever is smaller. However, a Special Permit for an Accessory Dwelling Unit exceeding fifty percent site coverage rule can be issued.
At least one 1 off-street parking space is required for each Accessory Dwelling Unit (ADU).
The ADU and primary residence cannot be sold separately or divided into separate entities.
Either the primary dwelling or the ADU must be occupied on a year-round basis. Short term rentals cannot occur in both units.
See the full text here: Zoning Ordinance Section VII C. Accessory Dwelling Units
Brewster, MA
Brewster, MA Accessory Dwelling Unit (ADU) Rules
As of 12.08/2025
What you need to know:
Brewster, 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 Brewster are outlined below.
Type of ADU permit required:
ADUs in Brewster 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 a maximum of 1,000 square feet.
ADUs can be attached, detached, or built within the main house.
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.
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.
Short-term rentals are not allowed. The minimum rental period for an ADU in Brewster is ten months.
The ADU must have a similar architectural style to the main house.
The main house and the ADU must be owned by the same person(s).
Resources: