Vermont Act 47 of 2023 allows homeowners to convert their single-family home to a duplex. Some potential issues include maintenance of shared spaces (roofs, walls, plumbing, electric wiring, etc.). Vermont requires that the property on which an ADU lies be owner-occupied. Figure out early on whether you want to sell your new unit, since selling the unit will require a zoning permit to formally change the use of your property.
If you wish to sell your new unit as a separate property to your own, check your local zoning bylaws for regulations surrounding lot subdivision. Lot subdivision is the process of, legally, dividing your lot into multiple discrete sections. For instance, if you live on a three-acre lot in a residential district that requires lots to be at least one acre, and you want to build a new unit separate from your home, you could site and sell the new unit as a separate structure on a separate one-acre parcel, subdividing the previously three-acre lot into a two-acre lot and a one-acre lot. Your town may or may not have subdivision regulations, but creating a new lot in Vermont always requires a state subdivision permit as well. This is in addition to any local permitting and subdivision regulations.
If you are seeking to subdivide, the new unit will need to comply with the same setback and lot coverage regulations set forth in your local zoning bylaws.
In New Hampshire, local governments can prevent ADUs from being sold as condos. Check the local zoning and subdivision regulations for more information.
See also: RENTING