ADU · Ulster County

Can you build an ADU in Rosendale, NY?

Town of Rosendale has 9 districts. 8 districts allow ADUs with occupancy restrictions, 1 does not. Check your address to confirm the district that applies to your parcel:

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What the Rosendale code says

One accessory dwelling unit is allowed with a house in every district except I-1, and no use permit is needed for the unit itself, but the owner has to live in either the house or the unit. The unit cannot be bigger than the house and cannot be a short-term rental.

Conditions the code attaches:

The owner of the parcel has to keep their primary home in either the principal dwelling or the accessory unit.
One accessory unit per qualifying parcel. Any further dwelling counts as a principal dwelling and takes the district's full lot and density standards.
The unit cannot exceed the gross floor area of the principal dwelling, and it cannot have more than two bedrooms.
A detached unit, or an expansion of the house's footprint to hold the unit, has to meet the district setback, lot coverage and height limits and goes through site plan review.
A unit built entirely inside the existing house is allowed as a principal use.
An existing garage, shed or outbuilding can hold the unit only if it meets the district setbacks, or a variance is obtained.
The unit cannot be used as a short-term transient rental, and no short-term rental permit will be issued for it until ten years after it was permitted.
An accessory unit is not allowed with a multifamily dwelling, or with a commercial or industrial use.
At least one off-street parking space is required for the unit, and it cannot sit in the front yard setback.
Outside a sewer district, Ulster County Department of Health approval of the septic is needed before a building permit.
Outside a water district, the unit connects to the principal dwelling's water system, unless a licensed engineer certifies that a connection is not feasible.
The unit must sit on a permanent foundation, and the parcel cannot carry an open building violation unless the unit cures it.
The Town Board can set a yearly limit on the number of accessory dwelling unit permits it issues.
Where the lot has acreage enough to support more than one principal use, the owner may instead build the new unit as an additional principal dwelling.
That additional principal dwelling carries the district's full bulk and density requirements.

How big an ADU can be in Rosendale

Size limits are set per district, and a unit inside the house is a different standard from a detached one. These are the figures the code publishes.

Accessory dwelling unit

100% of the principal dwelling

A, A1, R1, R2, R2A, R3, B1, B2 · owner-occupancy required · § 75-28.3(I) — an accessory dwelling unit shall not exceed the gross floor area of the principal dwelling unit; § 75-28.3(G) — owner occupancy required

What the Rosendale 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
A Residence	1.5 ac	50 / 30 / 50 ft	35 ft	Occupancy restricted
A-1 Trailer	1.5 ac	50 / 30 / 50 ft	35 ft	Occupancy restricted
R-1 Residence	1 ac	35 / 20 / 35 ft	35 ft	Occupancy restricted
R-2 Residence	1 ac	35 / 20 / 35 ft	35 ft	Occupancy restricted
R-2a Residence	1 ac	35 / 20 / 35 ft	35 ft	Occupancy restricted
R-3 Residence	0.17 ac	25 / 10 / 25 ft	35 ft	Occupancy restricted
B-1 General Business	0.23 ac	35 / 12.5 / 35 ft	30 ft	Occupancy restricted
B-2 Business	0.23 ac	40 / 25 / 40 ft	40 ft	Occupancy restricted
I-1 Light Industrial	0.46 ac	50 / 25 / 50 ft	40 ft	No

A Residence, A-1 Trailer - The minimums here do not vary with utility service.

Minimum lot dimensions are also governed by the supplementary regulations at §§ 75-12 through 75-17.

R-1 Residence - The minimum lot drops to 0.75 acre with community sewer or water, and to 0.5 acre with both.

§§ 75-12 through 75-17 hold further regulations on minimum lot dimensions.

R-2 Residence, R-2a Residence - The minimum lot drops to 0.75 acre with community sewer or water, and to 12,500 sq ft with both, where the width falls to 80 ft and the side yard to 12.5 ft.

§§ 75-12 through 75-17 hold further regulations on minimum lot dimensions.

R-3 Residence - The minimums shown apply only to a lot with community sewer or community water. The schedule sets no standard for a lot with neither.

Density for a multifamily or two-family building is calculated under § 75-28.D(5) rather than from the schedule.
Lot area for a mixed-use lot or building is set under § 75-15.
Minimum lot dimensions are also governed by the supplementary regulations at §§ 75-12 through 75-17.

B-1 General Business - A one- or two-family dwelling takes the R-2 District's lot and yard dimensions: at least 1 acre, 0.75 acre with community sewer or water, and 12,500 sq ft with both. On Main Street in the Hamlet of Rosendale the R-3 District's standards apply instead.

The district has a second row for Main Street in the Hamlet of Rosendale: 5,000 sq ft of lot, 50 ft width, no front and no side yard, a 20 ft rear yard, 40 ft height and 50% coverage.
Multifamily and two-family density is calculated under § 75-28.D(5) rather than from the schedule.
Lot area for a mixed-use lot or building is set under § 75-15.
§§ 75-12 through 75-17 hold further regulations on minimum lot dimensions.
The R-2 dimensions for a dwelling run a 100 ft width, 35 ft front and rear yards, 20 ft sides and 30% coverage; with both services the width is 80 ft and the side yard 12.5 ft.

B-2 Business - A one- or two-family dwelling takes the R-2 District's lot and yard dimensions: at least 1 acre, 0.75 acre with community sewer or water, and 12,500 sq ft with both, where the width falls to 80 ft and the side yard to 12.5 ft.

Multifamily and two-family density is calculated under § 75-28.D(5) rather than from the schedule.
Lot area for a mixed-use lot or building is set under § 75-15.
§§ 75-12 through 75-17 hold further regulations on minimum lot dimensions.
The R-2 dimensions for a dwelling run a 100 ft width, 35 ft front and rear yards, 20 ft sides and 30% coverage.

I-1 Light Industrial - No residential density is published for this district: the schedule prints not permitted in the area per dwelling unit column.

Minimum lot dimensions are also governed by the supplementary regulations at §§ 75-12 through 75-17.

ADUs vs. short-term rentals in Rosendale

Short-term rentals allowed with registration for Town of Rosendale. A short-term transient rental permit is required under Local Law No. 5 of 2024. On receipt of a permit the rental is permitted as an accessory use in the A, A-1, B-1, B-2, R-1, R-2, R-2a and R-3 districts. 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. Municipal source

Good to know

Residential lot minimum0.17–1.5 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/RO0511
Building dept(845) 658-3159

ADU FAQ — Rosendale, NY

Are ADUs allowed in Rosendale, NY?

Town of Rosendale has 9 districts. 8 districts allow ADUs with occupancy restrictions, 1 does not. Check your address with the free ADU checker, or confirm with the building department at (845) 658-3159.

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

No district in Town of Rosendale requires a special-use permit for an ADU - 8 districts allow ADUs with occupancy restrictions, 1 does not. Site-plan review or a building permit may still apply.

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

Short-term rentals allowed with registration for Town of Rosendale. 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 Rosendale

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 Rosendale, priced by size.

How we know this

Sections analyzed: § 75-28.3 Accessory dwelling units · § 75-28.3(D) Zoning districts · § 75-28.3(G) Owner occupancy · § 75-28.3(I) Minimum gross floor area · § 75-28.3(J) Number of accessory apartments · § 75-28.3(K) Construction · 75 Attachment 1 Schedule of Permitted Uses · § 75-28.4(E)(1)
Districts confirmed: 9 of 9 — 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 Rosendale: 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 Rosendale 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) 658-3159 before relying on any answer. Source: the Offsite / Aldo zoning dataset.