Washington

Vermont has one of the strongest statewide ADU permitted-use mandates in the country. Under 24 V.S.A. § 4412(1)(E), no municipal bylaw may exclude as a permitted use one ADU located within or appurtenant to a single-family dwelling on an owner-occupied lot — applying to ATTACHED, INTERIOR, and DETACHED ADUs alike, subject only to flood-hazard and fluvial-erosion bylaws. Act 179 (2020) further reduced parking burdens (no more parking required for an ADU than for the primary residence) and clarified detached-ADU eligibility. The HOME Act (Act 47, S.100, 2023) deepened the preemption: ADUs cannot be subjected to MORE STRINGENT review or zoning criteria than single-family homes; municipalities must allow duplexes anywhere single-family is allowed, four-plexes on lots with water/sewer, and a baseline 5 units/acre. Combined effect: Vermont preempts not only ADU exclusion but ADU disparate treatment, and pairs that with broader missing-middle preemption. The ADU may be up to 30% of the primary dwelling's habitable floor area or 900 sqft, whichever is larger.

The state preemption regime applies to MUNICIPAL bylaws, not to the contract-based covenants that govern common-interest communities under VCIOA. A homeowner in a Vermont HOA whose CC&Rs prohibit ADUs cannot rely on § 4412 to override that prohibition. Practical impact is limited because Vermont has comparatively few large master-planned HOA communities relative to Sun Belt states.

Vermont operates one of the most aggressive consumer-facing ADU financing programs in the country: the Vermont Housing Improvement Program (VHIP) 2.0, administered by the Agency of Commerce and Community Development through a network of regional housing nonprofits. VHIP 2.0 provides up to $50,000 per unit as a forgivable grant or 0% interest forgivable loan to property owners to bring rental units up to Vermont Rental Housing Health Code or to CREATE NEW UNITS, including ADUs. The program requires a 20% owner match ($10,000 against a $50,000 award) and rent-cap compliance at HUD Fair Market Rent for 5 or 10 years depending on the loan structure. The program flows through Champlain Housing Trust, Downstreet, NeighborWorks of Western Vermont, RuralEdge, and Windham & Windsor Housing Trust. The Vermont Housing Finance Agency (VHFA) provides first-mortgage financing through its standard programs (no ADU-specific overlay) and the Vermont Bond Bank funds the broader infrastructure that makes ADU-bearing lots serviceable.

• Vermont Housing Improvement Program (VHIP) 2.0 — ADU and rental rehab grants
• Vermont Housing Finance Agency (VHFA) — first-mortgage and homeowner programs
• Vermont State Housing Authority — ADU information and tenant pairing

Vermont has no statewide pre-approved ADU plan library, but the policy package is comparatively rich: VHIP 2.0 funds construction (covered in stateFinancing), the HOME Act (Act 47, 2023) imposes a non-discrimination review floor, and the Act 250 (state environmental review) reforms in Act 47 reduce trigger thresholds for housing within designated downtown / village / growth areas. Vermont's Designation Programs (Downtown, Village Center, New Town Center, Neighborhood Development Area) confer state benefits — sales-tax reallocation, priority project review, expedited Act 250 — that flow to ADU-bearing residential development inside those geographies. There is no statewide impact-fee preemption analogous to Utah's IADU exemption; impact fees are capped procedurally under 24 V.S.A. ch. 131 but not waived for ADUs as a class.

• HOME Act non-discrimination review floor — ADUs may not be subject to more stringent review or zoning criteria than single-family homes. Combined with the existing § 4412 permitted-use mandate, this functions as a state-level streamlined-review requirement.
• Act 250 housing-trigger reforms (Act 47, 2023) — Raises the unit-count trigger threshold for Act 250 jurisdictional review on housing within designated downtowns, village centers, and Neighborhood Development Areas, removing a state-level review hurdle that had previously caught smaller infill housing projects (including some ADU-bearing rehabs).
• ACCD Designation Programs (Downtown, Village Center, NDA) — Suite of state designations conferring tax credits, sales-tax reallocation, and expedited Act 250 review on residential projects in the designated boundary. ADU-bearing rehabs and new construction within designated areas access this benefit stack.