ADU · Ulster County

Can you build an ADU in Denning, NY?

Town of Denning has 3 districts. All districts allow ADUs with occupancy restrictions. Check your address to confirm the district that applies to your parcel:

Check my address for ADU feasibility → Free · no account needed to start

What the Denning code says

An in-law apartment is limited to someone related to the owner of the house, so it cannot be rented to a tenant at large. Subject to that, it is allowed in all three districts with Planning Board site plan review and no special permit.

Conditions the code attaches:

The apartment is for individuals related to the owner of the primary dwelling, so it cannot be let to an unrelated tenant.
It must be a room or suite of rooms connected to the main house; the code lists no detached in-law apartment.
Planning Board site plan review is required, but no special permit is, and site plan review is not a power to bar the use itself.
The code sets no size limit for the apartment and no separate minimum lot size for it.
Up to three principal residences are allowed on one lot if each would meet the district's lot area, width and yard rules on its own, subject to site plan review.

What the Denning 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
H Hamlet District	1 ac	25 / 20 / 30 ft	35 ft	Occupancy restricted
R Rural District	5 ac	40 / 25 / 40 ft	35 ft	Occupancy restricted
P Provincial District	10 ac	40 / 25 / 40 ft	35 ft	Occupancy restricted

H Hamlet District - The minimum lot area applies to each dwelling, so it is land per unit. On top of it, § 270A requires a development envelope of 33,000 contiguous square feet of buildable land, with a minimum horizontal dimension of 50 ft in any direction.

Buildable land excludes wetlands, watercourses, conservation buffers, floodways, slopes over 25%, parts of the lot under 51 ft wide and easement-encumbered land.
Minimum road frontage is 50 ft on a town road and 50 ft on a county road.
The front yard is measured from the right-of-way or street line, except where that right-of-way is under 50 ft wide, when it is measured from a line 25 ft from and parallel to its center line.
A subdivision may include one lot up to 0.2 acre (8,712 sq ft) under the minimum, but no more than one such lot.

R Rural District - A development envelope of at least 50,000 square feet of buildable land, at least 50 ft across, is required. A manufactured home park needs a special permit, and inside one sites are at least 10,000 sq ft, at most 2 units per acre and no more than 50 in a park.

Buildable land excludes wetlands, watercourses, conservation buffers, floodways, slopes over 25%, parts of the lot under 51 ft wide and land under an easement.
In a park, homes and accessory structures stand back 200 ft from any street or right-of-way, 150 ft from any property line and 40 ft from the center line of an internal private street.
A park also needs 75 ft between homes, a 100 ft landscaped buffer around it, and central water and central sewage approved by the Ulster County Department of Health.
Minimum road frontage is 100 ft on a town road and 100 ft on a county road.
Where the road right-of-way is under 50 ft wide, the front yard is measured from a line 25 ft from its center line rather than from the street line.
A subdivision may include one lot up to 0.2 acre (8,712 sq ft) below the minimum, but only one such lot.

P Provincial District - The minimum lot area applies to each dwelling, so it is land per unit. On top of it, § 270A requires a development envelope of 50,000 square feet of buildable land, with a minimum horizontal dimension of 50 ft.

Buildable land excludes wetlands, watercourses, conservation buffers, floodways, slopes over 25%, parts of the lot under 51 ft wide and easement-encumbered land.
Minimum road frontage is 150 ft on a town road and 100 ft on a county road.
The front yard is measured from the right-of-way or street line, except where that right-of-way is under 50 ft wide, when it is measured from a line 25 ft from and parallel to its center line.
A subdivision may include one lot up to 0.2 acre (8,712 sq ft) under the minimum, but no more than one such lot.

ADUs vs. short-term rentals in Denning

No local short-term-rental law on record - which is not the same as permission for Town of Denning. The Town of Denning has no local short-term rental law. That is not a yes, so confirm with the town before counting on renting a home short term. 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 minimum1–5 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codewww.denningny.gov/wp-content/uploads/2023/05/TOD-ZONING-LAW-2019.pdf
Building dept(845) 985-2285

ADU FAQ — Denning, NY

Are ADUs allowed in Denning, NY?

Town of Denning has 3 districts. All districts allow ADUs with occupancy restrictions. Check your address with the free ADU checker, or confirm with the building department at (845) 985-2285.

Do I need a special permit for an ADU in Denning?

No district in Town of Denning requires a special-use permit for an ADU - 3 districts allow ADUs with occupancy restrictions. Site-plan review or a building permit may still apply.

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

No local short-term-rental law on record - which is not the same as permission for Town of Denning. 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 Denning

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $200k–265k 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 Denning, priced by size.

How we know this

Sections analyzed: § 200 Schedule of District Use Regulations and Appendix A Use Schedule (In-law Apartment, R in H, R and P); Article V definition of In-Law Apartment; § 350 Site Plan Approval; § 210 Principal Residential Buildings Per Lot
Districts confirmed: 3 of 3 — every mapped district.
Last reviewed: Apr 2026
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 Denning: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Ulster County · All Ulster County towns

ADU information for Town of Denning is compiled from the municipal code (last reviewed Apr 2026) 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) 985-2285 before relying on any answer. Source: the Offsite / Aldo zoning dataset.