Accessory Dwelling Unit (ADU) Information

State of Massachusetts Accessory Dwelling Unit Information
https://www.mass.gov/info-details/accessory-dwelling-units

Town of Plymouth Zoning Bylaw §201-3:
Accessory Dwelling Unit: A self-contained detached or attached housing unit, inclusive of sleeping, cooking and sanitary facilities on the same lot as the principal single-family dwelling and that is accessory to an owner-occupied Single-Family Dwelling located in a Residential or Mixed Use Zoning District. Only one ADU shall be allowed on a Lot.

General Requirements:

• Remain in single ownership with the principal Single-Family Dwelling;
• Not be used as a short-term rental unit as defined by MGL c. 64G;
• Be located on the same Lot as the principal Single-Family Dwelling;
• Maintain a separate entrance, either directly from the outside or through an entry
   hall or corridor shared with the principal dwelling sufficient to meet the requirements of the state building code for safe egress;
• Not be larger in floor area than 900 square feet; and
• Complies with the parking requirements (based on total bedroom count on the Lot) of the Zoning Bylaw.

How to Apply

Step 1: File a zoning application. Your application should include:
 1. A site plan including setbacks and dimensions
 2. A floor plan with a layout of the existing and proposed living space

Step 2: File a building permit.
File a new construction application if the ADU will be a new detached structure.
File an addition/alteration application if the ADU will be within or added on to the existing dwelling.

*Please note that building permit applications for ADU's will only be accepted if you have an approved zoning permit