ADU · Monroe County

Can you build an ADU in Clarkson, NY?

Town of Clarkson has 3 districts. All districts allow ADUs with a special-use permit. Check your address to confirm the district that applies to your parcel:

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What the Clarkson code says

An accessory dwelling unit, governed by § 140-23.4, needs a special permit in all three residential districts. It may be a detached structure in AR and RS-20, but in RS-10 it must be located within the primary structure.

Conditions the code attaches:

It must be accessory to a single-family dwelling, and a property may have no more than one.
The unit's own side and rear setbacks are 15 ft in AR and 10 ft in RS-20 and RS-10. Lot size, width, front setback, coverage and height follow the primary use.
The stated purpose includes letting residents remain in their homes while obtaining extra income, security, companionship or services.
The maximum floor area, bedroom count, owner-occupancy and parking rules are not confirmed. Confirm them with the building department at (585) 637-1145.

What the Clarkson 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
Agricultural Residential	2 ac	40 / 25 / 30 ft	35 ft	Special permit
Residential Suburban — 20,000 sq ft	0.46 ac	40 / 10 / 30 ft	35 ft	Special permit
Residential Suburban — 10,000 sq ft	0.23 ac	40 / 10 / 30 ft	35 ft	Special permit

Agricultural Residential - A lot fronting a major road owes a 75 ft front setback. A two-family dwelling takes the same dimensions as a single-family, so a second unit needs no extra land, but it is a specially permitted use rather than a right.

Agricultural operations need 5 acres and 250 ft of width, with a 100 ft front yard, 35 ft sides and a 60 ft rear.
The height cap does not apply to barns, silos, water towers or tanks, windmills or other farm buildings on active farmland.
Keeping farm animals needs 5 acres, keeping chickens 3 acres and keeping bees 2 acres, each with 30 ft side and rear setbacks.
The accessory dwelling unit and the short-term rental are also specially permitted uses.
Accessory structures take 15 ft side and rear yards and a 20 ft height cap.

Residential Suburban — 20,000 sq ft - A two-family dwelling takes the same 20,000 sq ft as a single-family, and a detached accessory dwelling unit is available on top under § 140-23.4, so a minimum lot can reach three units. Both the two-family and the accessory unit need their own special permit.

A lot fronting a major road owes a 75 ft front setback.
Any structure other than a dwelling or attached garage owes a 10 ft rear setback, and accessory structures take 10 ft side yards and a 20 ft height cap.
A public park or playground, a religious or educational institution, and an animal hospital or grooming shop each need a full acre; a kennel needs an acre with 30 ft side and rear yards.
Agricultural operations need 5 acres on 200 ft of width, and a golf course needs 50 acres.
Keeping chickens needs 3 acres and keeping bees 2 acres, each with 30 ft side and rear yards.

Residential Suburban — 10,000 sq ft - A two-family dwelling takes the same 10,000 sq ft and 75 ft as a single-family, but only as new construction: converting an existing house into two units is prohibited at any lot size.

This is the only district in the town reaching multifamily, in two tiers: up to a 4-unit dwelling takes 20,000 sq ft on 100 ft of width, and over four units a full acre on the same 100 ft.
Both tiers are specially permitted, governed additionally by § 140-23.17, and both raise the height cap to 40 ft against the 35 ft for one- and two-family forms.
Every nonresidential use takes 20,000 sq ft on 100 ft of width; a short-term rental is the exception on setbacks, taking a 25 ft front yard rather than 40 ft, on 75 ft of width.
A lot fronting a major road owes a 75 ft front setback.
Any structure other than a dwelling or attached garage owes a 10 ft rear setback, and accessory structures take 10 ft side yards and a 20 ft height cap.

ADUs vs. short-term rentals in Clarkson

Short-term rentals allowed with local rules for Town of Clarkson. Clarkson regulates short-term rentals in § 140-23.21 of its zoning code, separately from bed-and-breakfasts. Whether a permit or registration, an occupancy cap or an owner-occupancy rule applies is not confirmed, so confirm with the building department before counting on the use. 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 minimum0.23–2 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityRG&E territory.
Zoning codeecode360.com/48554267
Building dept(585) 637-1145

ADU FAQ — Clarkson, NY

Are ADUs allowed in Clarkson, NY?

Town of Clarkson has 3 districts. All districts allow ADUs with a special-use permit. Check your address with the free ADU checker, or confirm with the building department at (585) 637-1145.

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

Yes. Every district in Town of Clarkson requires a special-use permit for an ADU rather than allowing one as of right. Check the conditions attached to it before you design.

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

Short-term rentals allowed with local rules for Town of Clarkson. 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 Clarkson

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $200k–260k 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 Clarkson, priced by size.

How we know this

Sections analyzed: Ch. 140 Art. 20 use tables (Specially Permitted Uses → Accessory Uses block); § 140-23.4 Accessory Dwelling Units; district dimensional tables
Districts confirmed: 3 of 3 — every mapped district.
Last reviewed: 2026-08-13
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 Clarkson: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Monroe County · All Monroe County towns

ADU information for Town of Clarkson is compiled from the municipal code (last reviewed 2026-08-13) 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 (585) 637-1145 before relying on any answer. Source: the Offsite / Aldo zoning dataset.