ADU · Ulster County

Can you build an ADU in Rochester, NY?

Town of Rochester has 10 districts. 7 districts allow ADUs with occupancy restrictions, 2 do not. 1 district has incomplete data - verify with the building department at (845) 626-7561. Check your address to confirm the district that applies to your parcel:

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What the Rochester code says

An accessory dwelling unit is permitted in the AR3, AB3, R1, R2, R5, H and B districts, interior to the house or in a detached accessory structure, and is not permitted in IND or NR. The owner has to keep their primary home in either the main house or the accessory unit.

Conditions the code attaches:

In PL-10 the answer is unresolved: the schedule of district uses shows an accessory unit there, the § 140-13.1.D list of districts does not, and § 140-8 makes the written text prevail.
The unit is capped at 750 sq ft or the gross floor area of the principal dwelling, whichever is less, with a minimum of 350 sq ft and at most 2 bedrooms.
The Building Inspector issues an ordinary residential building permit, with no Planning Board special use permit; site plan review applies only where the lot is non-conforming as to lot size.
Renting the accessory unit short term is barred under § 140-13.1.F.3, and a deed restriction has to be filed with the Ulster County Clerk before the certificate of occupancy.
Ulster County DOH septic adequacy approval is required before the building permit, and the water system must connect to the principal dwelling's unless a licensed engineer certifies it infeasible.
One accessory unit per qualifying parcel is the maximum, and the Town Board can cap by resolution how many accessory unit permits are issued in a year.

What the Rochester 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-3 Local Agricultural	3 ac	35 / 40 / 40 ft	35 ft	Occupancy restricted
AB-3 Agricultural Business	3 ac	35 / 40 / 40 ft	35 ft	Occupancy restricted
R-1 Neighborhood Residential	1 ac	10 / 25 / 25 ft	35 ft	Occupancy restricted
R-2 Low Density Residential	2 ac	35 / 40 / 40 ft	35 ft	Occupancy restricted
R-5 Rural Conservation	5 ac	50 / 50 / 50 ft	35 ft	Occupancy restricted
H Hamlet	1 ac	10 / 10 / 15 ft	35 ft	Occupancy restricted
I Industrial	1.5 ac	75 / 35 / 35 ft	35 ft	No
NR Natural Resources	1.5 ac	35 / 35 / 35 ft	35 ft	No
B Business	1 ac	35 / 25 / 25 ft	35 ft	Occupancy restricted
PL-10 Preserved Land	10 ac	75 / 75 / 75 ft	35 ft	—

A-3 Local Agricultural - A nonresidential use may cover 35% of the lot, against the 20% shown.

Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

AB-3 Agricultural Business - On Planning Board certification the lot density may rise by 1.5 times, taking 3.0 acres per unit to 2.0 acres, but only for green-energy, energy-conservation, passive-house or affordable housing development.

The affordable-housing route needs at least one unit, or 25% of units, deed-restricted in perpetuity.
A nonresidential use may cover 35% of the lot, against the 20% shown.
Where permitted uses including a residential one share a structure, the required lot area is the larger of the two; in separate structures it is the sum of both (§ 140-10(B)(2)).
Article V sets further per-use lot area exceptions.
Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

R-1 Neighborhood Residential, B Business - The minimum lot drops to 0.5 acre where the lot has central sewer and water.

On Planning Board certification the lot density may rise by 1.5 times, 1.0 acre per unit becoming 0.67 acre, but only for green-energy, energy-conservation, passive-house or affordable housing.
The affordable-housing route needs at least one unit, or 25% of units, deed-restricted in perpetuity.
Where permitted uses including a residential one share a structure, the required lot area is the larger of the two; in separate structures it is the sum of both (§ 140-10(B)(2)).
Article V sets further per-use lot area exceptions.
Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

R-2 Low Density Residential - The minimum lot area is one figure for residential and non-residential use alike, and it does not change where central sewer and water are available.

The code also sets a minimum lot frontage and a maximum number of stories for this district in Appendix B, neither of which is among the figures shown.
Performance standards under § 140-20 may apply.

R-5 Rural Conservation - A nonresidential use takes 300 ft of lot width and depth, 75 ft yards on every side, and up to 20% coverage.

Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

H Hamlet - The minimum lot drops to 13,000 sq ft where the lot has central sewer and water.

On Planning Board certification the lot density may rise by 1.5 times, 1.0 acre per unit becoming 0.67 acre, but only for green-energy, energy-conservation, passive-house or affordable housing.
The affordable-housing route needs at least one unit, or 25% of units, deed-restricted in perpetuity.
Where permitted uses including a residential one share a structure, the required lot area is the larger of the two; in separate structures it is the sum of both (§ 140-10(B)(2)).
Article V sets further per-use lot area exceptions.
Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

I Industrial - A nonresidential use takes 225 ft of lot width and depth, 75 ft side and rear yards, a 45 ft height limit and up to 50% coverage.

Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

NR Natural Resources - A nonresidential use takes 225 ft of lot width and depth, a 100 ft front yard, 75 ft side and rear yards, a 45 ft height limit and up to 50% coverage.

Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

PL-10 Preserved Land - A nonresidential use takes 100 ft yards on every side and up to 15% coverage.

Appendix B also sets a minimum lot frontage and a maximum number of stories.
Performance standards under § 140-20 may apply.

ADUs vs. short-term rentals in Rochester

Short-term rentals allowed with registration for Town of Rochester. A short-term rental permit is required in the Town of Rochester. New permits for a rental that is not owner-occupied are capped, so availability is limited. 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 minimum1–5 ac — an ADU still has to fit the district's lot and setback envelope.
Energy codeNew York stretch energy code adopted (Local Law No. 3 of 2023) — applies to new ADU construction.
UtilityCentral Hudson territory.
Zoning codeecode360.com/RO1435
Building dept(845) 626-7561

ADU FAQ — Rochester, NY

Are ADUs allowed in Rochester, NY?

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

No district in Town of Rochester requires a special-use permit for an ADU - 7 districts allow ADUs with occupancy restrictions, 2 do not. Site-plan review or a building permit may still apply.

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

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

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What an ADU costs to build in Rochester

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 Rochester, priced by size.

How we know this

Sections analyzed: § 140-13.1 Accessory Dwelling Units; Appendix C Schedule of District Uses (L.L. 6 of 2024)
Districts confirmed: 9 of 10 — 1 not yet analyzed, so this page does not answer for it.
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 Rochester: 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 Rochester 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) 626-7561 before relying on any answer. Source: the Offsite / Aldo zoning dataset.