ADU · Monroe County
Can you build an ADU in Irondequoit, NY?
Town of Irondequoit has 4 districts. All districts allow ADUs with a special-use permit. Check your address to confirm the district that applies to your parcel:
What the Irondequoit code says
In R-1, R-2, R-3 and R-R, one additional in-law dwelling unit, attached or detached, is allowed only with a special use permit from the Town Board. Planning Board site plan approval under Article XV is also required.
Conditions the code attaches:
- District bulk rules apply: § 235-10 caps lot coverage at 25% for principal and accessory buildings together, and § 235-9 limits a single-family dwelling to two stories and 30 ft.
- The code publishes no floor area cap for the unit, and whether the minimum floor area rule reaches a detached in-law unit is unsettled.
- § 235-12A sets a minimum floor area for a residential building other than an approved tiny house, 1,300 sf in R-R, 1,100 sf in R-1, 900 sf in R-2, 750 sf in R-3.
- The code sets no owner occupancy, kinship, age or no-rent condition for the unit, and does not say whether the Town Board attaches conditions to an individual permit.
- An attached garage may provide living quarters on the second floor but may not create a second dwelling unit (§ 235-13D(4)), so a garage apartment has to come through the in-law permit.
- Confirm the details with the Building Department at (585) 336-6020.
What the Irondequoit 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 |
|---|---|---|---|---|
| R-1 Residential | 0.22 ac | 30 / 8 / 30 ft | 30 ft | Special permit |
| R-2 Residential | 0.22 ac | 30 / 8 / 30 ft | 30 ft | Special permit |
| R-3 Residential | 0.22 ac | 30 / 8 / 30 ft | 30 ft | Special permit |
| R-R Rural Residential | 1.03 ac | 50 / 15 / 50 ft | 30 ft | Special permit |
R-1 Residential - The side setback shown is a formula at the district's minimum width: 10% of lot width, never less than 5 ft and capped at 15 ft in R-1, so it grows on a wider lot. A corner lot owes the full front setback on every yard adjacent to a street.
- Minimum total floor area is 1,100 sq ft whether the dwelling is one storey or one and a half to two storeys, with a minimum ground floor area of 600 sq ft on the taller forms.
- Floor area counts only conditioned interior space along the main foundation walls; attached garages, three-season rooms, porches and breezeways are excluded.
- An approved tiny house is expressly exempt from the minimum building size.
- A through lot owes the full front setback on both streets for principal and accessory structures alike, with boundary fencing excepted.
- A deck attached to the principal structure may come within 20 ft of the rear lot line, where the building itself may not.
- Detached accessory structures may not sit in a front yard and, private garages excepted, must keep four feet to a rear or side property line.
R-2 Residential - The side yard is 10% of the lot width, never less than 5 ft and capped at 15 ft, so it grows on a wider lot until it reaches 15 ft. A corner lot owes the full front setback on every yard next to a street.
- A through lot owes the front setback on both streets for the house and accessory structures, boundary fencing excepted.
- The 900 sq ft minimum counts only conditioned interior space; attached garages, three-season rooms, porches and breezeways do not count.
- A dwelling of one and a half to two storeys also needs at least 550 sq ft of ground floor area.
- An entry porch, deck or stoop under 60 sq ft and 6 ft deep may project into the front yard, keeping 20 ft to the front lot line if attached; 20 sq ft and 4 ft if the house fails the front setback.
- A deck attached to the house may come within 20 ft of the rear lot line.
- Detached accessory structures may not stand in a front yard and, except private garages, must keep 4 ft from side and rear property lines.
R-3 Residential - The 8 ft side yard is a formula, not a fixed figure: 10% of lot width, never less than 5 ft and capped at 15 ft in R-3, so it grows on a wider lot. A corner lot owes the full 30 ft front setback on every yard next to a street.
- A through lot owes the front setback on both streets, for principal and accessory structures alike, with boundary fencing excepted.
- The 750 sq ft minimum counts only conditioned interior space along the main foundation walls; attached garages, three-season rooms, porches and breezeways are excluded.
- A dwelling of one and a half to two storeys also needs a ground floor area of at least 500 sq ft.
- An approved tiny house is exempt from the minimum building size.
- A deck attached to the principal structure may come within 20 ft of the rear lot line, closer than the building itself may sit.
- Detached accessory structures may not sit in a front yard and, private garages excepted, must keep four feet to a rear or side property line.
R-R Rural Residential - The front setback is a range, not just a floor: a house must sit at least 50 ft back and no more than 75 ft from the front lot line. The side yard is 10% of lot width, never less than 5 ft and capped at 25 ft, so it grows on a wider lot.
- A corner lot owes the full front setback on every yard adjacent to a street, and a through lot owes it on both streets for principal and accessory structures alike, boundary fencing excepted.
- On a lot inside a curve, the front yard is measured from the nearest point of the arc.
- A deck attached to the principal structure may come within 20 ft of the rear lot line, where the building itself may not.
- A porch, deck or stoop and its covering may project into the required front yard if it is under 60 sq ft and less than six feet deep, and an attached platform must keep 20 ft to the front lot line.
- Detached accessory structures may not sit in a front yard and, private garages excepted, must keep four feet to a rear or side property line.
- The 1,300 sq ft minimum floor area counts only conditioned interior space and expressly exempts an approved tiny house; one and a half to two storey forms also need a 700 sq ft ground floor.
ADUs vs. short-term rentals in Irondequoit
Short-term rentals allowed with local rules for Town of Irondequoit. Short term rentals are prohibited here except under a town permit. § 235-76.50 states the prohibition and § 235-76.52 requires the permit, both in Article XIIIB of Chapter 235, so the use is available only on the terms that article sets. 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 minimum0.22–1.03 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityRG&E territory.
- Zoning codeecode360.com/6407632
- Building dept(585) 336-6020
ADU FAQ — Irondequoit, NY
Are ADUs allowed in Irondequoit, NY?
Town of Irondequoit has 4 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) 336-6020.
Do I need a special permit for an ADU in Irondequoit?
Yes. Every district in Town of Irondequoit 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 Irondequoit?
Short-term rentals allowed with local rules for Town of Irondequoit. 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.
What an ADU costs to build in Irondequoit
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 Irondequoit, priced by size.
How we know this
- Sections analyzed
- § 235-8B(1)(d) and (2)(d); § 235-4 (Apartment, accessory); §§ 235-9 to 235-12; § 235-13D(4); §§ 235-90 to 235-92
- Districts confirmed
- 4 of 4 — every mapped district.
- Last reviewed
- 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 Irondequoit: 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 Irondequoit is compiled from the municipal code (last reviewed 2026-08-07) 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) 336-6020 before relying on any answer. Source: the Offsite / Aldo zoning dataset.