Eventually, it will be important to have a clear portrait of your needs so you and your contractor can plan accordingly. But in the beginning, all you need is to answer some basic questions that will help clarify your options. The specifics of your plan will no doubt change along the way.

Siting Your ADU

The first step is figuring out what can go where. Here are some questions to consider:

  • Is there room on your property to build a completely new structure? 
  • Do you have an existing outbuilding like a garage that can be repurposed? 
  • Is your house large enough to divide into two or more units?
  • How will people access the new unit? Where will they park? Check out this page for site considerations. 

To answer these questions, you may need to find out where the boundaries of your property are. Do not make assumptions about the location of your property line. If you have a survey of your property, then you should be able to find boundary markers. If you don’t have a survey, you may need one. Talk to your neighbors to see where they think the boundaries are.

Should I Rent or Sell My ADU?

Decide early in the process whether you want to rent or sell your new unit. There are pros and cons to each option. Renting pays back the construction costs over time, while selling can eliminate construction debt quickly. Even though the end product may look the same, these are very different options with different rules. The tools on this site assume that your ADU, as is Vermont and New Hampshire law, will be located on an owner-occupied lot, meaning that you live on the same site as the ADU (regardless of whether you live in the ADU or the main house–that’s up to you). If you are planning to sell the ADU, please refer to the SELLING and PERMITTING pages for more information.

How Big Should My ADU Be?

By Vermont state law, an ADU can be up to 30% of the square footage of the home or 900 ft², whichever is larger. This means that if your house is 3,000 ft² or less, the largest your ADU can be is 900 ft². If your house is larger than 3,000 ft², then multiply your home’s square footage by 0.3 to find the maximum square footage. Some town zoning bylaws permit even larger ADUs, so check with your town zoning officer.

When planning the dimensions of your new unit, you’ll need to consider local zoning code. Where on the property will the ADU be located? Will it obey setback and lot coverage requirements? Refer to the HOW TO READ A ZONING BYLAW page for more information, and be sure to consult your local zoning administrator before hiring an architect or swinging a hammer.

Planning for Utilities

Building a new unit will likely require electrical and/or plumbing work. Here are a few things to consider:

  • Does your property have access to town sewer or water service? 
  • Does your property have a private water supply and/or septic system? If so, you may need increased capacity to accommodate the new unit. See PERMITTING for more information.
  • How will the ADU receive power? Will the new unit be metered separately from the existing unit? 
  • Talk with your contractor and your local utility companies, and refer to the PERMITTING page for more information about connecting your new unit to utilities. 

Next comes DESIGN and FINANCING.