ADU rules in Stowe

Section 4.1(A) of Stowe's Zoning Regulations allows "one (1) attached or detached dwelling unit, which is accessory to a single-family dwelling" in any district, and Table 6.1 lists "Dwelling Unit, Accessory (Accessory Apartment)" as a permitted (P) use in all eleven mapped districts: RR-1, RR-2, RR-3 and 5, UMR, HT, MRV, MRC, VR, VC, LVC/MC and WBCSD. A detached backyard cottage therefore needs only a Zoning Administrator permit, not a Development Review Board hearing. It must meet the ordinary district setbacks, coverage and height in Table 6.2, hold no more than two bedrooms, and be served by the same access and driveway as the house. The one exception is the Forest Reserve District, whose Section 5.14 use list is limited to agriculture and forestry as permitted uses and whose conditional uses expressly exclude residential uses and lodging.

Section 4.1(A) covers attached and detached units in a single sentence, so a basement conversion, a rear addition or a unit over an attached garage is treated exactly like a detached cottage and carries the same size, bedroom, parking and dimensional conditions. Section 16.200 confirms the arrangement: a "Unit, Single-Family Dwelling" is "a building containing a single dwelling unit, which may include an accessory apartment." Section 16.198 then excludes an accessory apartment from the definition of dwelling unit "for the purpose of density calculations," so an internal ADU does not consume the lot's Table 6.3 density allowance. Interior work that creates the unit is a change of use, so it is not covered by the Section 2.5(2)(F) exemption for interior alterations and still needs a zoning permit.

Section 4.1(A)(1) caps the ADU at 900 square feet of habitable floor area where the single-family dwelling has under 1,800 sq ft of habitable floor area. Section 4.1(A)(2) allows 50 percent of the house's habitable floor area once the house exceeds 1,800 sq ft, but "in no case" may the unit exceed the greater of 2,500 sq ft or 30 percent of the house's total habitable floor area, so a 5,000 sq ft house supports a 2,500 sq ft ADU and a 10,000 sq ft house a 3,000 sq ft one. Habitable floor area is defined in 4.1(A)(3) as space used for living, sleeping, eating and cooking, excluding utility spaces, unfinished basements, attics, garages and similar unfinished areas. Two further limits ride along: no more than two bedrooms (4.1(A)(4)) and full compliance with the district's dimensional requirements (4.1(A)(5)). These caps were raised by the January 10, 2024 rewrite, whose amendment record describes Section 4.1 as changed "to increase the maximum habitable floor area for accessory dwelling units."

Stowe imposes no owner-occupancy condition on an ADU. Section 4.1(A) lists seven requirements (two size rules, the habitable-area definition, the two-bedroom cap, dimensional compliance, on-site parking and a shared driveway) and none of them asks the owner to live on the property; neither does the Section 16.1 definition of Accessory Dwelling nor the Table 6.1 use entry. That makes Stowe more permissive than the state floor, which only obliges municipalities to allow an ADU "within or appurtenant to a single-family dwelling on an owner-occupied lot" (24 V.S.A. § 4412(1)(E)) and expressly preserves bylaws that are "less restrictive of accessory dwelling units" (§ 4412(1)(F)(i)). Owner occupancy does matter for one thing: only an owner whose Primary Residence is in Stowe can obtain the Homestead Short-Term Rental Licenses that sit outside the town's 850-license STR cap.

Section 4.1(A)(6) requires on-site parking for the residents of the ADU "in accordance with Table 14.2." That cross-reference is stale: parking moved to Section 15 in the 2022 and 2024 rewrites (Section 14 is now Signs), and the operative Table 15.2, Minimum Parking Requirements, sets "Residential Dwelling Unit: 1" space per dwelling unit. So the ADU adds one off-street space, minimum nine by eighteen feet and maintained year-round under Section 15.2, and it has to be reached by the same access and driveway as the primary house (Section 4.1(A)(7)). The DRB can modify parking requirements in the circumstances listed in Section 15.3. One space per unit is also the most Vermont law lets a town require where municipal utilities exist: 24 V.S.A. § 4414(4) provides that in any district served by municipal sewer and water infrastructure that allows residential uses, "a municipality shall not require more than one parking space per dwelling unit."

Accessory dwellings are a permitted (P) use in every district on Table 6.1, so the Zoning Administrator issues the permit administratively with no Development Review Board hearing. Section 2.5(1) requires that zoning permit before any land development begins, Section 3.16(B) exempts "a single-family or two-family dwelling, and any accessory uses or structures to such a dwelling" from DRB site plan review, and Section 2.10 requires a Zoning Certificate of Occupancy before the unit is occupied (residential accessory structures and additions under 500 sq ft sited at least 15 feet from a setback line are exempt from that step). Permits do not take effect until the appeal period runs, and permitted-use work must be substantially complete within three years (Section 2.9). Two mapped overlays can still add a board: inside the Ridgeline and Hillside Overlay District no zoning permit may issue without prior DRB approval (Section 9.4(1)), and inside the Stowe Historic Overlay District the Historic Preservation Commission reviews the design, though the Zoning Administrator may approve a single-family dwelling and its residential accessory structures administratively on a positive SHPC recommendation (Section 10.5(3)(A)).

Zoning places no limit on how long an ADU may be leased; an October 30, 2018 amendment deliberately revised the definition of Dwelling Unit "eliminating the requirement that they can only be rented or leased on a weekly, monthly or longer basis." Short-term renting is governed instead by the Short-Term Rental Ordinance adopted July 22, 2026, which reaches any rental of a dwelling unit to the transient, traveling or vacationing public for fewer than 30 consecutive days and more than 14 days per calendar year. Every dwelling unit needs its own registration, STR License and $100 fee, so a house and its ADU are two separate registrations; a Designated Responsible Person must arrive in person within 45 minutes of a call from Stowe fire or police, and the Fire Department needs year-round lock-box access. Beginning September 15, 2026 the Town will issue no more than 850 STR Licenses, with newcomers selected through a July lottery, and licenses are generally not transferable on an arms-length sale. Owners whose Primary Residence is in Stowe sit outside that cap: Section IV(F) lets them hold Homestead STR Licenses for up to two dwelling units on their homestead property, which is precisely the house-plus-ADU case, so long as the property stays their primary residence for the whole license year. Vermont's 3 percent short-term rental tax and Division of Fire Safety public-building rules apply on top.