On Thursday May 15, 2025 Town Council affirmatively approved amendments to the Town's Accessory Dwelling Unit (ADU) ordinance. The amendments addressed recent revisions to Chapter 40A of the General Laws, the State Zoning Act, as set forth in the Affordable Homes Act including revising the definition of Accessory Dwelling Unit, revising use and dimensional requirements, floor areas definition, and clarifying parking restrictions and no owner-occupancy requirement for Accessory Dwelling Units.
An accessory dwelling unit (ADU) is a self-contained dwelling unit that provides complete independent living facilities for one or more persons, as outlined herein, including permanent provisions for living, sleeping, eating, cooking and sanitization, incorporated within a lawful principal dwelling or within a detached building accessory to and on the same lot and in the same ownership as a lawful principal dwelling use.
The ADU shall 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. ADUs shall have a maximum gross floor area that is not larger than 1/2 of the gross floor area of the principal dwelling unit (exclusive of floor area that converted to the ADU), or 900 square feet, whichever is smaller, unless special permit relief is granted with respect to the requirements of 240-47.2.C(4) with regard to square footage.
The Town has put together the ADU Frequently Asked Questions as a resource to answer common questions about the ADU ordinance.
The Town's Health Department has put together the Options for Resolving Your Bedroom Count Issue to provide guidance for the definition of a bedroom as well as potential options for resolving your bedroom count should your application for a permit consist of too many bedrooms.
To learn more about rental registration please visit the Health Division webpage accessible by clicking HERE.
Discussion about adopting a zoning ordinance to allow Accessory Dwelling Units (ADUs) commenced with an initial review of the Cape Cod Commission's Model ADU Ordinance and consideration of policy issues conducted by the Town Council's Zoning & Regulatory Subcommittee in 2020. The initial draft was then referred to Town staff for technical and legal review, as well as review against the "Housing Choice" legislation adopted by the Commonwealth on January 14, 2021. Town Council affirmatively approved the ADU ordinance in July of 2021 as written with one amendment.
The ADU ordinance was amended in 2025 in response to revisions to Chapter 40A of the General Laws, the State Zoning Act, as set forth in the Affordable Homes Act, which was signed into law on August 6, 2024, as Chapter 150 of the Acts of 2024. The Affordable Homes Act permitted Accessory Dwelling Units (ADUs) to be built by-right in single family zoning districts. Barnstable already had an ADU ordinance; however, certain provisions were determined to be inconsistent with State law. As a result, amendments were proposed including revising the definition of Accessory Dwelling Unit, revising use and dimensional requirements, floor areas definition, and clarifying parking restrictions and no owner-occupancy requirement for Accessory Dwelling Units. Town Council affirmatively approved the amendments to the ADU ordinance in May of 2025.
To help keep the public informed of zoning issues in Barnstable, the Town offers e-mail notices of current and upcoming zoning amendment proposals and related meetings. Sign up HERE.
Town Staff: James Kupfer, AICP, Director of Planning & Development
Phone: 508-862-4735
Email: James.Kupfer@town.barnstable.ma.us
Photo credit: ABCs of ADUs