Accessory Dwelling Units

What is an ADU?

An accessory dwelling unit (ADU) is a dwelling located on the same lot as a single-family home.  Think an apartment with its own independent facilities for cooking, bathing, and sleeping.  It can be part of the home or in a separate structure (existing or new).  There are size limits, but it is a great way to create more housing - for rental income or for a family member.  Also referred to as accessory apartments, ADUs do not require complicated permitting.  A State water/wastewater permit and a Town zoning permit are generally all that is required.

ADU Parameters

• One ADU allowed per single-family home.
• The landowner must reside on the property - either in the single-family home or the ADU.
• Wastewater disposal and water supply must be addressed.  Typically requires a State permit.
• Maximum size 900 square feet or larger as outlined below:
  • Single family dwelling 1200-1600 square feet - maximum ADU size is 75% of the principal dwelling
  • Single family dwelling 1600-4000 square feet - maximum ADU size is 1200 square feet
  • Single family dwelling over 4000 square feet - maximum ADU size is 30% of the principal dwelling

* Note - size refers to the livable floor area of the structure - i.e., areas that are finished/conditioned/heated.   In other words, ADUs can have decks, garages, screened porches, etc., and these areas do not count toward the maximum size allowance.

ADU Permitting

For permitting, contact the Hinesburg Zoning Administrator (Jim Jarvis, jjarvis@hinesburg.org, 802-482-4213).  ADUs are addressed in section 5.9 of the Hinesburg Zoning Regulations; however, portions of this section have been superseded by changes to State law in the last couple years, including the HOME Act (Act 47) that became effective on July 1, 2023.  The Town is limited to regulating size, owner-occupancy, and water/wastewater capacity.  Hinesburg Zoning Regulations on the number of bedrooms, parking spaces, access drives, and conditional use review are no longer valid.

After you have a sense of the process and an idea of what you’d like to create, the first step is to figure out how to address water/wastewater needs and get the necessary State water/wastewater permit.  You will likely need to hire a licensed designer to evaluate the capacity of your existing water/wastewater system, or design a new water/wastewater system for the ADU.  See below for a State flyer with more information on water/wastewater permitting.

ADU Information

• ADU information page, VT Agency of Commerce & Community Development - https://accd.vermont.gov/housing/planning/adu
• ADU informational video, Hinesburg Affordable Housing Committee - https://www.hinesburg.org/affordable-housing-committee

ADU Incentives

The Vermont Housing Improvement Program (VHIP) offers grants up to $50,000 to create a new ADU.  More information about this program available online - https://accd.vermont.gov/housing/vermont-housing-improvement-program.  In our area, the program is managed by the Champlain Housing Trust.  They have a website with more specific information about the program - https://www.getahome.org/vermont-housing-improvement-program/.