Chittenden County, VT Accessory Structures: ADU Rules (2026)

Vermont counties have no operational government - county boundaries are judicial districts only, with no zoning, building, or land use authority. ADU rules are governed by 24 V.S.A. §4412(1)(E), strengthened by Act 47 of 2023 (the HOME Act). Under the statute, an ADU is a distinct unit clearly subordinate to a single-family dwelling with independent sleeping, food preparation, and sanitation facilities. Statewide standards: (1) the ADU may not exceed 30% of the primary dwelling's habitable floor area or 900 square feet, whichever is greater; (2) the property must have adequate wastewater capacity for both units; (3) a single-family dwelling with an ADU must be subject to the same review, dimensional, and other controls as a single-family dwelling without an ADU - meaning towns cannot impose extra parking, owner-occupancy, or design conditions specific to ADUs that they would not impose on a base single-family home. Towns may regulate location of an ADU through bylaws, but cannot prohibit one outright. Chittenden County towns (Burlington, South Burlington, Williston, Essex, Colchester, Shelburne, Winooski, Hinesburg, Charlotte, Jericho, Milton, Richmond, St. George, Underhill, Westford, Bolton, Buel's Gore, Huntington) administer the state baseline through local zoning. Most allow ADUs up to 900 sq ft as of right; some permit larger. The Vermont Housing Improvement Program (VHIP) funds eligible owners up to $50,000 to create rental ADUs.