ADU · Dutchess County

Can you build an ADU in Union Vale, NY?

Town of Union Vale has 9 districts. 7 districts allow ADUs with a special-use permit, 2 do not. Check your address to confirm the district that applies to your parcel:

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What the Union Vale code says

An accessory apartment needs a special use permit in RD10, RA5, RA3, R1.5, R1 and H, in the house or a separate nondwelling structure, and in NC only within the house; it is prohibited in TC and A. The owner must live in one of the two units, and the other may be rented.

Conditions the code attaches:

For an apartment within the house the owner may live in either unit; with a separate nondwelling structure, the principal dwelling must stay owner-occupied.
Habitable floor area is capped at 35% of the principal dwelling's or 1,000 sq ft, whichever is more restrictive, with a 450 sq ft minimum and at most two bedrooms.
On a conversion the lot must be at least the district minimum acreage or three acres, whichever is less restrictive; a separate nondwelling structure needs 80%-100% of minimum lot area by district.
No exterior change may alter or extend the foundation area by more than 150 sq ft or substantially modify the structure's appearance as a single-family dwelling.
The unit must be self-contained, with separate cooking, sleeping and sanitary facilities, and any added exterior entrances must be at the side or rear.
Building Department: (845) 724-5600.

What the Union Vale code indicates by district

The table below shows how each district treats ADUs, alongside the lot and setback standards that govern a second unit. District boundaries and conditions vary, so treat this as a starting point and confirm the district that applies to your parcel.

District	Min lot	Setbacks F / S / R	Max height	ADU
Rural Development 10 District	10 ac	100 / 75 / 100 ft	35 ft	Special permit
Residential Agricultural 5 District	5 ac	100 / 50 / 100 ft	35 ft	Special permit
Residential Agricultural 3 District	3 ac	75 / 35 / 50 ft	35 ft	Special permit
Residential 1.5 District	1.5 ac	50 / 35 / 40 ft	35 ft	Special permit
Residential 1 District	1 ac	35 / 35 / 35 ft	35 ft	Special permit
Hamlet District	1.5 ac	40 / 25 / 40 ft	35 ft	Special permit
Neighborhood Commercial District	1 ac	40 / 25 / 40 ft	35 ft	Special permit
Town Center District	—	20 / 25 / 80 ft	35 ft	No
Airport District	2.5 ac	100 / 50 / 50 ft	35 ft	No

Rural Development 10 District - At least 85% of the lot must be left as open space, a separate test from the coverage cap. Parking areas and access driveways have their own setbacks of 75 ft front, 50 ft side and 50 ft rear.

Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Lot frontage is 375 ft, the same as the lot width at the building line.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Residential Agricultural 5 District - At least 80% of the lot must be left as open space, a separate test from the coverage cap. Parking areas and access driveways have their own setbacks of 60 ft front, 25 ft side and 40 ft rear.

Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Lot frontage is 275 ft, the same as the lot width at the building line.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Residential Agricultural 3 District - At least 75% of the lot must be left as open space, a separate test from the coverage cap. Parking areas and access driveways have their own setbacks of 45 ft front, 20 ft side and 25 ft rear.

Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Lot frontage is 225 ft, the same as the lot width at the building line.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Residential 1.5 District - At least 70% of the lot must be left as open space, a separate test from the coverage cap. Parking areas and access driveways have their own setbacks of 30 ft front, 20 ft side and 20 ft rear.

Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Lot frontage is 175 ft, the same as the lot width at the building line.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Residential 1 District - At least 65% of the lot must be left as open space, a separate test from the coverage cap. Parking areas and access driveways have their own setbacks of 25 ft front, 20 ft side and 15 ft rear.

Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Lot frontage is 150 ft, the same as the lot width at the building line.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Hamlet District - Lot frontage is 100 ft but width at the building line is 150 ft, so a lot that fronts the road adequately can still be too narrow where the house goes. At least 50% of the lot must be left as open space, a separate test from the coverage cap.

Parking areas and access driveways have their own setbacks of 25 ft front, 15 ft side and 15 ft rear.
Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Neighborhood Commercial District - Lot frontage is 100 ft but width at the building line is 150 ft, so a lot that fronts the road adequately can still be too narrow where the building goes. At least 40% of the lot must be left as open space, a separate test from the coverage cap.

Parking areas and access driveways have their own setbacks of 30 ft front, 15 ft side and 30 ft rear.
Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

Town Center District - Residential density is one dwelling unit per half acre before any approved density bonus, in place of a minimum lot area. The front setback is a range of 20 ft to 35 ft, so a building may not be set further back than 35 ft.

A commercial lot needs at least two acres, and a commercial building footprint is capped at 2,500 sq ft, or 4,000 sq ft for food and grocery store uses.
Residential development fronting Route 55 must give at least 15% of total building square footage to commercial uses, and the last 25% of units get no certificate of occupancy until that is complete.
The 25 ft side yard and 20 ft parking side setback may be cut to zero for zero-lot-line development authorised by special use permit where emergency vehicle access is adequate.
Commercial, multifamily, townhouse and mixed-use development must also meet the TC Design Standards at § 210 Attachment 3.
Parking areas and access driveways have their own setbacks of 20 ft front, 20 ft side and 30 ft rear, and parking must go to the rear or side of the principal building.
At least 50% of the lot must be left as open space, a separate test from the coverage cap.

Airport District - Lot frontage is 100 ft but width at the building line is 200 ft, so a lot that fronts the road adequately can still be too narrow where the building goes. At least 35% of the lot must be left as open space, a separate test from the coverage cap.

Parking areas and access driveways have their own setbacks of 35 ft front, 15 ft side and 20 ft rear.
Parking may not go in any front yard setback and must go to the rear or side of the principal building, with landscaping and screening under § 210-25B.
Coverage counts the footprint of all principal and accessory structures, excluding uncovered porches, terraces and steps.
These standards apply to permitted uses; Article VI may set extraordinary standards for special permit uses.

ADUs vs. short-term rentals in Union Vale

Short-term rentals allowed with local rules for Town of Union Vale. Short-term rental is a regulated use here: § 210-85A treats letting a dwelling unit for less than 30 days as an accessory use or supplementary business. Which districts it is allowed in, and whether a permit is needed, is not confirmed, so check with the town first. These are separate questions from whether you can build an ADU — a unit you're allowed to add isn't automatically one you're allowed to rent nightly, so check both.

Good to know

Residential lot minimum1–10 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/7977116
Building dept(845) 724-5600

ADU FAQ — Union Vale, NY

Are ADUs allowed in Union Vale, NY?

Town of Union Vale has 9 districts. 7 districts allow ADUs with a special-use permit, 2 do not. Check your address with the free ADU checker, or confirm with the building department at (845) 724-5600.

Do I need a special permit for an ADU in Union Vale?

It depends on the district: 7 of 9 require a special-use permit, the rest do not. Check the district that applies to your parcel before you design.

Can I use an ADU as a short-term rental in Union Vale?

Short-term rentals allowed with local rules for Town of Union Vale. ADU occupancy and short-term-rental rules are separate: an ADU you can build isn't automatically one you can rent nightly. Confirm both before you count on STR income.

Run the free ADU check for your parcel →

What an ADU costs to build in Union Vale

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $210k–275k at a standard finish, and the per-square-foot rate comes in above a full house because the kitchen, bath, panel and heating plant cost the same either way. See the full cost to build an ADU in Union Vale, priced by size.

How we know this

Sections analyzed: Ch. 210 Attachments 2 and 3, District Schedules of Use Regulations (Commercial and Residential); § 210-56B standards; § 210-56G(1)
Districts confirmed: 9 of 9 — every mapped district.
Last reviewed: 2026-08-16
Not covered here: Overlay districts, the zoning map, and any conditions attached to an individual parcel. Size limits and owner-occupancy terms sit in the code section above, not in this summary.

More on Union Vale: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Dutchess County · All Dutchess County towns

ADU information for Town of Union Vale is compiled from the municipal code (last reviewed 2026-08-16) and provided for decision-support only — not legal or architectural advice. ADU eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; verify with the building department at (845) 724-5600 before relying on any answer. Source: the Offsite / Aldo zoning dataset.