Plainfield, MA


Plainfield, MA Accessory Dwelling Units (ADU) Rules

City Acceptance Rating: 9/10 (10 is most accepting)

What you need to know: 

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.

Plainfield also provides guidelines to convert a single family property to a multi-family property. If homeowners use this approach to add an additional apartment getting financing will be easier and they will maximize their home’s value. Multi-family conversions can only use existing space in the single family home (no additions or construction).

Type of Permit Required:

Plainfield allows both attached and detached accessory dwelling units (ADUs) to be built by right.

If a lot is nonconforming, an ADU requires a special permit.

ADU rules in Plainfield:

  • An ADU can be added to either a single or two-family dwelling.

  • It must be a fully separate living space including its own kitchen, bath, and egress.

  • Only one Accessory Apartment can be added to a residential lot.

  • The lot in question must conform to its zoning district’s rules (e.g size and street frontage).

  • The ADU and site plan must maintain the residential and rural character of the neighborhood. Exterior modification, including new detached structures must match the existing architectural elements of the home.

  • New entrances shall be located facing the side or front yard of the lot.

  • Adding an ADU to an original building or a backyard ADU is permissible as long as it is subordinate to the dwelling.

  • ADUs can not be larger than one third (33%) of the existing residential living space or nine hundred (900) square feet, whichever is less.

  • Off-street parking spaces must conform to the schedule in Section 5.3.

  • A sanitarian or professional engineer, registered in the Commonwealth of Massachusetts, must certify that the sewage disposal system can accommodate the additional apartment.

Read the full bylaw here: Zoning Ordinance, Section 8.2 Accessory Apartments and Multi-family Conversions