Greenfield, MA

Greenfield, MA Accessory Dwelling Unit (ADU) Rules

City Acceptance Rating: 10/10 (10 is most accepting)



What you need to know: 

Greenfield revised its rules for Accessory Dwelling Units in 2020 to make it EXTREMELY easy 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)!

ADUs can be added to two and single-family homes by right! This means there is no public hearing process and owners of two-family homes with landlord experience can add another unit.

Type of Permit Required:

Greenfield allows all types of ADUs by right. This included space conversion, detached ADUs, additions, and conversion of existing accessory structures (barns, garages, etc).

ADU Rules in Greenfield:

  • The additional unit must have its own kitchen, bathroom, and means of egress.

  • An ADU can be added to single-family and two-family properties.

  • One of the two dwellings must be owner-occupied.

  • The single-family character of the home must be retained and new entrances must be located on the side or rear of the house.

  • New detached structures or additions must match the character of the existing house.

  • Any stairways, access, or egress alterations serving the Accessory Dwelling Unit shall be hidden from public view.

  • The ADU can not be larger than 900 sq. ft. or one-third the total gross floor area of the home, whichever is greater.

  • Once built, the ADU cannot be enlarged beyond the square footage approved with the original permit.

  • An Accessory Dwelling Unit may not be occupied by more than three (3) people.

  • The ADU must have 2 or fewer bedrooms.

  • Detached ADUs are considered Accessory Structures and must follow rules as such.

  • The entire property must have at minimum 2 parking places and cannot have more than 4.

  • Septic system capacity must be validated by the Board of Health before a permit issued.

  • Deviations from the above can be granted to accommodate people with a disability and persons with limited mobility.


See the full text here: Zoning Ordinance Section 200-7.18. Accessory Dwelling Units, page 119

ADU Bylaw

Dimensional Requirements