ADU · Monroe County
Can you build an ADU in Rochester, NY?
City of Rochester has 7 districts. All districts prohibit ADUs. Check your address to confirm the district that applies to your parcel:
What the Rochester code says
Rochester's zoning code creates no accessory dwelling unit. A second unit is treated as a principal use, so it is only possible where the code allows a two-family or multifamily dwelling.
Conditions the code attaches:
- The only accessory living space listed for a residential use is a guesthouse or servants quarters in the rear yard, not including kitchen facilities (§ 120-163A(1)(g)).
- That space may house only people employed on the premises or occasional guests of the household, and may not be used as a rental unit or for permanent occupancy by anyone else.
- Without cooking facilities it is not a dwelling unit under § 120-208, which requires integrated facilities for living, sleeping and cooking.
- In R-1, § 120-10 prohibits converting a residential structure to increase the number of residential units except as otherwise provided in the chapter, and § 120-19 says the same in R-2.
- R-2 allows two-family dwellings by right and multifamily dwellings by special permit (§ 120-17 and § 120-18H); R-3 allows two-family and multifamily dwellings by right (§ 120-26).
- The same accessory use list applies to residential uses in C-1, C-2, C-3 and O-S. The building department can confirm for a specific property at (585) 428-6526.
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 |
|---|---|---|---|---|
| Low-Density Residential | 0.11 ac | 20 / 5 / 20 ft | 35 ft | No |
| Medium-Density Residential | 0.11 ac | 20 / 5 / 20 ft | 35 ft | No |
| High-Density Residential | 0.11 ac | 20 / 5 / 20 ft | — | No |
| Neighborhood Center District | — | - / 0 / 0 ft | — | No |
| Community Center District | 0.06 ac | — | — | No |
| Regional Destination Center District | — | - / 0 / 0 ft | — | No |
| Open Space District | — | 35 / - / - ft | — | No |
Low-Density Residential - The front yard has a maximum as well as a minimum. The minimum is the average front yard depth on the two adjoining lots, or the block frontage average, or 20 ft, and the maximum is the average of the adjoining lots or the block frontage.
- A single-family attached building of two units is stated per unit: 3,000 sq ft of lot and 30 ft of frontage each, against the 5,000 sq ft a detached house needs, so a pair takes 6,000 sq ft on 60 ft.
- A nonresidential use owes 10 ft at the side with 25 ft for both, against a dwelling's 5 ft and 15 ft, and its lot area, frontage and coverage are not stated.
- A building of three or more attached units is not available here, and an attached structure owes no side yard except where it adjoins a detached structure, when 5 ft and 15 ft apply.
- Minimum lot frontage is the average frontage of the lots on the block, so no fixed width is published for a detached house.
- The rear yard is 20 ft or the average rear yard setback on the block, but never less than 10 ft.
- An attached garage or carport must meet the principal front yard plus 10 ft, and detached accessory structures are limited to 15 ft in height.
Medium-Density Residential - The front yard has a maximum as well as a minimum. The minimum is the average front yard depth on the two adjoining lots, or the block frontage average, or 20 ft, and the maximum is the average of the adjoining lots or the block frontage.
- A single-family attached building of two units is stated per unit: 3,000 sq ft of lot and 30 ft of frontage each, against the 5,000 sq ft a detached house needs, so a pair takes 6,000 sq ft on 60 ft.
- A two-family dwelling takes 6,000 sq ft rather than 5,000, so the second unit costs 1,000 sq ft; the rear yard is 20 ft or the existing setback, never less than 10 ft.
- A multifamily building is stated per dwelling unit at 3,000 sq ft each with no flat lot minimum and no frontage requirement, roughly 14 units to the acre before coverage and height are tested.
- A nonresidential use owes 10 ft at the side with 25 ft for both, and its detached accessory structures 10 ft at side and rear; an attached garage or carport meets the principal front yard plus 10 ft.
- Minimum lot frontage for a detached house or a two-family dwelling is the average frontage of the lots on the block, so no fixed width is published.
- An attached principal structure needs no side yard, except where it adjoins a detached structure, when the 5 ft side and 15 ft combined apply.
High-Density Residential - There is no fixed height limit: the maximum building height is two times the width of the lot frontage, so 80 ft on the 40 ft minimum frontage and 200 ft on a 100 ft frontage.
- A single-family attached building of two units is stated per unit: 3,000 sq ft of lot and 30 ft of frontage each, against the 5,000 sq ft a detached house needs, so a pair takes 6,000 sq ft on 60 ft.
- A two-family dwelling takes 6,000 sq ft on 30 ft of frontage, against 5,000 sq ft on 40 ft for a detached house, so more land on less frontage, which also lowers the height available.
- A multifamily building of over three units needs 9,000 sq ft of lot and then 1,000 sq ft per unit for one- and two-bedroom units, rising to 1,800 sq ft per unit for three or more bedrooms.
- The rear yard is one third of the building height or 20 ft, whichever is greater, and multifamily side yards are one third of the height or 10 ft, so the 20 ft shown is a floor.
- The front yard minimum is the average depth on the two adjoining lots, or the block average, or 20 ft, and there is a maximum set by the adjoining-lot or block average.
- An attached principal structure needs no side yard, except where it adjoins a detached structure, when the 5 ft side and 15 ft combined apply.
ADUs vs. short-term rentals in Rochester
No local short-term-rental law on record - which is not the same as permission for City of Rochester. Rochester has no local short-term rental law, but that is not permission: transient lodging is not a listed residential use in R-1, R-2 or R-3, so a rental there may already be unpermitted. Confirm with the Bureau of Zoning first. 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 minimum0.11 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityRG&E territory.
- Zoning codeecode360.com/8679474
- Building dept(585) 428-6526
ADU FAQ — Rochester, NY
Are ADUs allowed in Rochester, NY?
City of Rochester has 7 districts. All districts prohibit ADUs. Check your address with the free ADU checker, or confirm with the building department at (585) 428-6526.
Do I need a special permit for an ADU in Rochester?
No. No district in City of Rochester permits an ADU, so there is no permit to apply for. Codes change, so verify with the building department at (585) 428-6526 before ruling it out.
Can I use an ADU as a short-term rental in Rochester?
No local short-term-rental law on record - which is not the same as permission for City 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.
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–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 Rochester, priced by size.
How we know this
- Sections analyzed
- Ch. 120 §§ 120-8, 120-10, 120-17, 120-18, 120-19, 120-26; § 120-163A(1)(g) guesthouse or servants quarters; § 120-166; § 120-208
- Districts confirmed
- 7 of 7 — 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 Rochester: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Monroe County · All Monroe County towns
ADU information for City of Rochester is compiled from the municipal code (last reviewed 2026-08-12) 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) 428-6526 before relying on any answer. Source: the Offsite / Aldo zoning dataset.