ADU and Small Home Regulations in Massachusetts
The Affordable Home Act Passed!!! While we are updating our local rules pages to reflect the new law,
you can check out the new Mass.gov webpage with additional details and FAQ’s.
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The first step is knowing the rules
If you are interested in installing a granny flat (accessory dwelling unit), your first step is to review your local rules. Each town has differing rules relating to which zones ADUs can be installed in, maximum size, or rental restrictions.
Find your city’s ADU Rules:
Can’t find your city? We’ll research it.
Western Mass Cities That Allow Detached ADUs:
Shutesbury revised its rules for Accessory Dwelling Units in 2008 to make it easier for homeowners to add an additional dwelling unit to their properties. The city sees ADUs as a great to way help increase density and create high quality housing without sacrificing the character of the town. Since the bylaw was approved, there have been many ADUs added to homes including at least one backyard home (detached ADU)!
Plainfield loves ADUs and has a favorable permitting process. However, it is important to note that the town’s rules are very clear that the design and site plan must conform with the single family and rural characteristics of the town.
Detached ADUs are only allowed by Special Permit in its Village Center Districts. Conversion of existing space or additions are only allowed by right in its Village Center Districts.
Palmer allows both attached and detached accessory dwelling units (ADUs) to be built by special permit. However, it is important to note that the town’s rules are very clear that the design and site plan must conform with the single family and rural characteristics of the town.
Montague has very favorable rules related to backyard homes (ADUs). There are limited restrictions and their zoning bylaw overall does not place excessive regulations on what can be built on a someone’s land. Setback requirements are also some of the most accommodating in Western Mass. However, homeowners still need to apply for a special permit to build a detached ADU so it will be important to plan a project that considers neighbors and the public if your ADU will be visible from the street.
Greenfield revised its rules for Accessory Dwelling Units in 2016 to make it easier for homeowners to add an additional dwelling unit to their properties. The city sees ADUs as a great to way increase density and create high quality housing without sacrificing the character of the town. Since the bylaw was approved, there have been many ADUs added to homes including at least one backyard home (detached ADU)!
Great Barrington loves ADUs and allows them by right in all zoning districts. However, it is important to note that the backyard home cannot be greater than 650 SF. Additionally, if an ADU is proposed in an existing nonconforming structure, a special permit will be needed.
Great Barrington also defines a path to convert a single family property to a legal duplex or multifamily property. For eligible lots, this formal conversion will allow homeowners to maximize their property value. Duplexes and multifamily properties are discussed in section 8.1 and 8.3 of the zoning bylaw.
The town is also deliberating on new rules that would allow tiny homes on trailers! Stay tuned for more information and if you are a resident of Great Barrington contact the planning/zoning board to voice your support.
In 2014, Amherst joined many cities in MA by revising bylaws making it easier for homeowners to install accessory apartments in all zoning districts. They have very straight forward rules in their zoning ordinance, but design requirements are strict and certain neighborhoods are harder to obtain approvals than others due to fears about student tenants and noise.
In 2014, Northampton joined many cities in MA by revising its zoning bylaw to make it easier for homeowners to build accessory apartments in all zoning districts. They have attractive rules in their zoning ordinance and biggest restrictions are related to environmental protections.
Chesterfield joined many cities in MA by revising its zoning bylaw to make it easier for homeowners to build accessory apartments in most zoning districts.
In 2014, Easthampton joined many cities in MA by revising its zoning bylaw to allow homeowners to build accessory apartments in all zoning districts. Installations started slow and have been used primarily for aging parents or to help care for disabled family members.
Today – surging home prices, high rents, and unwanted gentrification have put the bylaw in the spotlight and have stimulated demand for detached accessory dwelling units (Backyard ADUs).
Cape Cod Cities That Allow Detached ADUs:
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.
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.
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!
Greater Boston Cities That Allow Detached ADUs:
Below is the full list of cities and town we’ve evaluated in Massachusetts.
Western Mass
Williamsburg does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Wilbraham does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Whately does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Sunderland does not have a section in its bylaw covering accessory dwelling units (ADUs). However, the town does allow two-family homes in all zoning districts except C-2. If your property has enough space you may be able to add backyard tiny home as a formal 2nd unit.
South Hadley does not have a bylaw for detached accessory dwelling units (ADUs). However, they do provide a path to convert single-family homes into duplexes following the rules in the town’s zoning ordinance.
Southampton does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Shutesbury revised its rules for Accessory Dwelling Units in 2008 to make it easier for homeowners to add an additional dwelling unit to their properties. The city sees ADUs as a great to way help increase density and create high quality housing without sacrificing the character of the town. Since the bylaw was approved, there have been many ADUs added to homes including at least one backyard home (detached ADU)!
Plainfield loves ADUs and has a favorable permitting process. However, it is important to note that the town’s rules are very clear that the design and site plan must conform with the single family and rural characteristics of the town.
Detached ADUs are only allowed by Special Permit in its Village Center Districts. Conversion of existing space or additions are only allowed by right in its Village Center Districts.
Palmer allows both attached and detached accessory dwelling units (ADUs) to be built by special permit. However, it is important to note that the town’s rules are very clear that the design and site plan must conform with the single family and rural characteristics of the town.
Montague has very favorable rules related to backyard homes (ADUs). There are limited restrictions and their zoning bylaw overall does not place excessive regulations on what can be built on a someone’s land. Setback requirements are also some of the most accommodating in Western Mass. However, homeowners still need to apply for a special permit to build a detached ADU so it will be important to plan a project that considers neighbors and the public if your ADU will be visible from the street.
Monson does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Leverett does not allow detached accessory dwelling units (ADUs). The town allows attached accessory dwelling units under extremely strict circumstances. The town also requires the special permit to be renewed every 2 years. We do not recommend building an ADU of any kind in Leverett.
Ludlow does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Granby does not allow attached or detached accessory dwelling units (ADUs). The town also specifically prohibits the conversion of single family homes into duplexes or mutli-family homes.
Huntington does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Hatfield does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Hadley does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
Greenfield revised its rules for Accessory Dwelling Units in 2016 to make it easier for homeowners to add an additional dwelling unit to their properties. The city sees ADUs as a great to way increase density and create high quality housing without sacrificing the character of the town. Since the bylaw was approved, there have been many ADUs added to homes including at least one backyard home (detached ADU)!
Great Barrington loves ADUs and allows them by right in all zoning districts. However, it is important to note that the backyard home cannot be greater than 650 SF. Additionally, if an ADU is proposed in an existing nonconforming structure, a special permit will be needed.
Great Barrington also defines a path to convert a single family property to a legal duplex or multifamily property. For eligible lots, this formal conversion will allow homeowners to maximize their property value. Duplexes and multifamily properties are discussed in section 8.1 and 8.3 of the zoning bylaw.
The town is also deliberating on new rules that would allow tiny homes on trailers! Stay tuned for more information and if you are a resident of Great Barrington contact the planning/zoning board to voice your support.
Deerfield does not allow detached accessory dwelling units (ADUs). The town allows attached accessory dwelling units under extremely strict circumstances. ADUs can only be used to provide in home care for someone who needs help with Activities of Daily Living and the Special Permit issued has to be renewed every 5 years.
Belchertown does not allow detached accessory dwelling units (ADUs). Granny flats must be constructed within existing space or as an addition.
In 2014, Amherst joined many cities in MA by revising bylaws making it easier for homeowners to install accessory apartments in all zoning districts. They have very straight forward rules in their zoning ordinance, but design requirements are strict and certain neighborhoods are harder to obtain approvals than others due to fears about student tenants and noise.
Cape Cod Area
Sandwich draws a distinction between “Accessory Dwelling Units” and “Accessory Apartments” and provide different rules for each.
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.
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.
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!
Greater Boston Area
