ADU · Erie County

Can you build an ADU in Tonawanda, NY?

City of Tonawanda has 10 districts. 6 districts allow ADUs with occupancy restrictions, 4 do not. Check your address to confirm the district that applies to your parcel:

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What the Tonawanda code says

The only accessory living space the City names is quarters for servants employed on the premises, allowed by right wherever a house is: R-1, R-2, R-C, C-1, C-2 and C-M. Whoever lives there has to work there. C-1A, the commerce park and the two industrial districts have none.

Conditions the code attaches:

The code sets no size, separation or approval standard for the quarters
R-2 also permits two-family and multifamily dwellings, dwelling groups, roominghouses and boardinghouses by right
C-1A permits no accessory use at all
In M-1 and M-2 an existing house may stay but may not gain units

What the Tonawanda 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
Single-Family Residence District	0.17 ac	25 / 5 / 25 ft	30 ft	Occupancy restricted
General Residence District	0.092 ac	25 / 5 / 25 ft	30 ft	Occupancy restricted
Residential-Restricted Business District	0.14 ac	25 / 5 / 25 ft	30 ft	Occupancy restricted
Neighborhood Shopping District	—	20 / 0 / 10 ft	—	Occupancy restricted
Neighborhood Shopping District	—	- / 0 / 10 ft	—	No
Central Retail District	—	0 / 0 / 10 ft	—	Occupancy restricted
General Commercial Services District	—	20 / 0 / 10 ft	—	Occupancy restricted
Manufacturing District	—	20 / 10 / 10 ft	—	No
Light Industrial District	—	20 / 10 / 10 ft	—	No
Spaulding Commerce Park District	—	20 / 10 / 10 ft	35 ft	No

Single-Family Residence District - The 7,500 sq ft is stated per dwelling unit, so a two-family here needs 15,000. No side yard may be less than 10% of the lot width or five feet, whichever is larger, and none need exceed ten feet.

On a 60 ft lot the least side yard is six feet and on a 100 ft lot ten
The two side yards together must total at least 25% of the lot width, capped at 25 ft
A single-family house with an attached garage must keep at least five feet on each side regardless
The rear yard is 25% of the lot depth and never less than 25 ft
A building need not stand back further than the average of the buildings within 150 ft either way, and in a residential district not less than that average, though nothing forces more than 50 ft
Attached dwellings are a separate and easier regime: a flat 4,000 sq ft on a 35 ft width with a 20 ft front yard and a 25 ft rear, and no side yard where two dwellings meet on a common line

General Residence District - The lot minimum is additive and the 4,000 sq ft buys the first unit only: each additional dwelling unit costs a further 2,000 sq ft, so a duplex needs 6,000 and a four-unit building 10,000.

Lot width works the same way, 50 ft for the first unit plus six feet for each one after
No side yard may be less than 10% of the lot width or five feet, whichever is larger, and none need exceed ten feet, so on a 60 ft lot the least is six feet
The two side yards together must total at least 25% of the lot width, capped at 25 ft
The rear yard is 25% of the lot depth and never less than 25 ft
A building need not stand back further than the average of the buildings within 150 ft either way, and in a residential district not less than that average, though nothing forces more than 50 ft
Attached dwellings are a separate and easier regime: a flat 4,000 sq ft on a 35 ft width with a 20 ft front yard and a 25 ft rear, and no side yard where two dwellings meet on a common line

Residential-Restricted Business District - The lot minimum is additive and the 6,000 sq ft buys the first unit only: each additional dwelling unit costs a further 2,500 sq ft, so a duplex needs 8,500. Width is 50 ft for the first unit plus six feet for each one after.

No side yard may be less than 10% of the lot width or five feet, whichever is larger, and none need exceed ten feet, so on a 60 ft lot the least is six feet
The two side yards together must total at least 25% of the lot width, capped at 25 ft
The rear yard is 25% of the lot depth and never less than 25 ft
A principal building that is not a dwelling takes a 15 ft side yard, or half the height of the building if that is greater
A building need not stand back further than the average of the buildings within 150 ft either way, and in a residential district not less than that average, though nothing forces more than 50 ft
Attached dwellings are a separate and easier regime: a flat 4,000 sq ft on a 35 ft width with a 20 ft front yard and a 25 ft rear, and no side yard where two dwellings meet on a common line

Neighborhood Shopping District - No side yard is required between commercial lots, but any side yard actually provided must be at least five feet. The 20 ft front yard deepens to 25 ft where off-street parking is provided in it.

A side yard used for vehicular ingress or egress must be at least 12 ft, and one used for both at least 25 ft
Against a lot in a residential district the side yard becomes 30 ft or the height of the building, whichever is greater, and the rear yard likewise
No lot area, lot width or height is set for a non-residential use: the lot is sized by the yard, open space and off-street parking requirements
Where a dwelling is permitted the lot minimum is 6,000 sq ft for the first unit plus 2,500 for each additional, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft

Neighborhood Shopping District - The chapter sets no front yard for this district at all, and that is a gap in the drafting rather than a zero, so confirm it with the City before siting a building.

No side yard is required between commercial lots, but any side yard actually provided must be at least five feet
A side yard used for vehicular ingress or egress must be at least 12 ft, and one used for both at least 25 ft
Against a lot in a residential district the side yard becomes 30 ft or the height of the building, whichever is greater, and the rear yard likewise
No lot area, lot width or height is set for a non-residential use: the lot is sized by the yard, open space and off-street parking requirements
Where a dwelling is permitted the lot minimum is 6,000 sq ft for the first unit plus 2,500 for each additional, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft

Central Retail District - No front yard is required at all here and no side yard between commercial lots, which together are what let a continuous downtown retail frontage exist.

Any side yard actually provided must be at least five feet, 12 ft if used for vehicular ingress or egress and 25 ft for both
Against a lot in a residential district the side yard becomes 30 ft or the height of the building, whichever is greater, and the rear yard likewise
No lot area, lot width or height is set for a non-residential use: the lot is sized by the yard, open space and off-street parking requirements
Where a dwelling is permitted the lot minimum is 6,000 sq ft for the first unit plus 2,500 for each additional, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft

General Commercial Services District - The 20 ft front yard deepens to 25 ft where off-street parking is provided in it. No side yard is required between commercial lots, but any side yard actually provided must be at least five feet.

A side yard used for vehicular ingress or egress must be at least 12 ft, and one used for both at least 25 ft
Against a lot in a residential district the side yard becomes 30 ft or the height of the building, whichever is greater, and the rear yard likewise
No lot area, lot width or height is set for a non-residential use: the lot is sized by the yard, open space and off-street parking requirements
Where a dwelling is permitted the lot minimum is 6,000 sq ft for the first unit plus 2,500 for each additional, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft

Manufacturing District - The 20 ft front yard rises to 50 ft where the building is opposite one or more lots in a residential district. The 10 ft side and rear yards apply between industrial lots, and both rise to 50 ft where the lot abuts a residential district boundary.

No lot area, lot width or height is set for a non-residential use: the lot is sized by the yard, open space and off-street parking requirements
Where a dwelling is permitted the lot minimum is 6,000 sq ft for the first unit plus 2,500 for each additional, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft

Light Industrial District - The 20 ft front yard rises to 50 ft where a building stands opposite a lot in any R district, and the 10 ft side and rear yards, which apply between industrial lots, rise to 50 ft where the lot abuts a residential district boundary.

Where a dwelling is permitted the lot needs 6,000 sq ft for the first unit plus 2,500 sq ft for each additional unit, on 50 ft of width plus six feet per additional unit
An attached dwelling takes a flat 4,000 sq ft on 35 ft of width

Spaulding Commerce Park District - Every yard here is priced by the neighbour: the 20 ft front yard becomes 30 ft where parking sits in front, and 50 ft where the site faces a residential district or use.

The 10 ft side yard becomes 35 ft for a commercial use or 50 ft for an industrial one against residential land, and falls to nothing where two commercial uses share a parking lot
The 10 ft rear yard becomes 30 ft or 50 ft on the same test
A further ten feet around the perimeter must be given over to a publicly accessible linear park, built and maintained by the owner under an access easement, on top of every yard above
The 35 ft height rises to 45 ft for a decorative peak or facade, and the 75% cap counts buildings, parking and every other impervious surface
No minimum lot area and no minimum lot width are set, though the code says lots under 100 ft are strongly discouraged
Residential use, outdoor storage, truck terminals, mini-storage, junkyards, cellular towers, car sales and adult uses are all prohibited outright

ADUs vs. short-term rentals in Tonawanda

No local short-term-rental law on record - which is not the same as permission for City of Tonawanda. The city has no local short-term rental law. That is not the same as permission, so confirm with the city before counting on renting a home short term. 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 minimum0.092–0.17 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityNational Grid territory.
Zoning codelibrary.municode.com/ny/tonawanda/codes/code_of_ordinances?nodeId=PTIICOOR_CH82ZO_ART5BURE
Building dept(716) 695-1806

ADU FAQ — Tonawanda, NY

Are ADUs allowed in Tonawanda, NY?

City of Tonawanda has 10 districts. 6 districts allow ADUs with occupancy restrictions, 4 do not. Check your address with the free ADU checker, or confirm with the building department at (716) 695-1806.

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

No district in City of Tonawanda requires a special-use permit for an ADU - 6 districts allow ADUs with occupancy restrictions, 4 do not. Site-plan review or a building permit may still apply.

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

No local short-term-rental law on record - which is not the same as permission for City of Tonawanda. 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 Tonawanda

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 Tonawanda, priced by size.

How we know this

Sections analyzed: § 82-203(2)a (R-1) · § 82-204 (R-2) · § 82-205 (R-C) · § 82-206 (C-1) · § 82-207 (C-1A) · § 82-208 (C-2) · § 82-209 (C-M) · § 82-209A (SCD) · §§ 82-210, 82-211 · § 82-201
Districts confirmed: 10 of 10 — every mapped district.
Last reviewed: 2026-09-10
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 Tonawanda: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Erie County · All Erie County towns

ADU information for City of Tonawanda is compiled from the municipal code (last reviewed 2026-09-10) 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 (716) 695-1806 before relying on any answer. Source: the Offsite / Aldo zoning dataset.