ADU · Erie County

Can you build an ADU in West Seneca, NY?

Town of West Seneca has 13 districts. All districts prohibit ADUs. Check your address to confirm the district that applies to your parcel:

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What the West Seneca code says

West Seneca has no accessory apartment. The letter A in the district name is what matters: R-90, R-75 and R-65 allow a single-family house only, while R-90A, R-75A, R-65A, R-50, R-100A, R-60A, C-1 and C-2 allow a two-family house by right.

Conditions the code attaches:

Only uses a district lists are allowed, and an unlisted use needs the chapter amended before a permit can issue
The districts that allow a two-family house also allow up to two long-term roomers or lodgers in a house
R-50 adds group and multiple-family dwellings, on a Town Board special permit
M-1 and M-2 permit no permanent dwelling, though M-1 allows caretaker or watchman quarters serving the industry
In M-1 a dwelling that existed when the chapter took effect may continue, provided it is not converted in any manner that increases the number of dwelling units

What the West Seneca 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-100A Residence	0.46 ac	40 / 10 / 50 ft	30 ft	No
R-90 Residence	0.28 ac	30 / 10 / 30 ft	30 ft	No
R-90A Residence	0.28 ac	40 / 10 / 30 ft	30 ft	No
R-75 Residence	0.23 ac	30 / 5 / 30 ft	30 ft	No
R-75A Residence	0.23 ac	40 / 5 / 30 ft	30 ft	No
R-65 Residence	0.2 ac	30 / 5 / 30 ft	30 ft	No
R-65A Residence	0.2 ac	40 / 5 / 30 ft	30 ft	No
R-60A Residence	0.23 ac	40 / 5 / 30 ft	30 ft	No
R-50 Residence	0.18 ac	30 / 5 / 30 ft	30 ft	No
C-1 Commercial	—	40 / 0 / 10 ft	40 ft	No
C-2 Commercial	—	40 / 0 / 10 ft	40 ft	No
M-1 Manufacturing	—	25 / 10 / 10 ft	40 ft	No
M-2 Manufacturing	—	25 / 10 / 10 ft	40 ft	No

R-100A Residence - A two-family dwelling needs 1,200 sq ft of livable floor area rather than the 900 sq ft shown. The 10 ft side yard is the one-side minimum and the 20 ft beside it is the total for both sides, so both bind.

A principal building that is not a dwelling takes 30 ft on each side, or the height of the building if that is greater
The 30 ft height limit is for a one- or two-family dwelling; a multiple dwelling or any other principal building may reach 40 ft unless the Town Board approves more
Where an apartment or two-family dwelling is permitted, the area of each dwelling unit must be approved by the Town Board
The lot minimum here is flat and does not increase for a second dwelling unit
An accessory building anywhere in a residence district is capped at 12 ft
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the principal buildings on the abutting lots fronting the same street

R-90 Residence, R-90A Residence - The 10 ft side yard is the one-side minimum and the 20 ft beside it is the total for both sides, so both bind. The 30 ft height limit is for a one- or two-family dwelling: a multiple dwelling or any other principal building may reach 40 ft unless the Town Board approves more.

The lot minimum here does not increase for a second dwelling unit.
An accessory building anywhere in a residence district is capped at 12 ft.
No lot coverage or impervious standard is set anywhere in the town.
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the principal buildings on the abutting lots fronting the same street.

R-75 Residence, R-75A Residence - The lot minimum shown covers the first dwelling unit only, and a second unit adds both land and frontage, so a duplex needs more lot than the figure shown. The 5 ft side yard is the one-side minimum and the 10 ft beside it is the total for both sides.

The 30 ft height limit is for a one- or two-family dwelling: a multiple dwelling or any other principal building may reach 40 ft unless the Town Board approves more.
An accessory building anywhere in a residence district is capped at 12 ft.
No lot coverage or impervious standard is set anywhere in the town.
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the principal buildings on the abutting lots fronting the same street.

R-65 Residence, R-65A Residence - The lot minimum shown covers the first dwelling unit only: a second unit adds 1,350 sq ft of land and ten feet of frontage. The 5 ft side yard is the one-side minimum and the 10 ft beside it is the total for both sides.

A two-family dwelling needs 1,200 sq ft of livable floor area rather than the 900 sq ft shown
A principal building that is not a dwelling takes 30 ft on each side, or the height of the building if that is greater
The 30 ft height limit is for a one- or two-family dwelling; a multiple dwelling or any other principal building may reach 40 ft unless the Town Board approves more
Where an apartment or two-family dwelling is permitted, the area of each dwelling unit must be approved by the Town Board
An accessory building anywhere in a residence district is capped at 12 ft
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the principal buildings on the abutting lots fronting the same street

R-60A Residence, R-50 Residence - The lot minimum shown covers the first dwelling unit only: a second unit adds 5,000 sq ft of land and ten feet of frontage. The 30 ft rear yard is a floor, since the code requires 30 ft or the height of the principal building, whichever is greater.

A two-family dwelling needs 1,200 sq ft of livable floor area rather than the 900 sq ft shown
A multiple dwelling takes 25 ft to each side, or half the building height if greater, with both sides together twice one side, which the Town Board may reduce on special circumstances or hardship
A principal building that is not a dwelling takes the same side yards as a multiple dwelling
The 30 ft height limit is for a one- or two-family dwelling; a multiple dwelling or any other principal building may reach 40 ft unless the Town Board approves more
An accessory building anywhere in a residence district is capped at 12 ft
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the principal buildings on the abutting lots fronting the same street

C-1 Commercial - No lot area and no frontage are required of a commercial building here. Side yards are not required either, but any side yard that exists must be at least 5 ft, 12 ft where it carries vehicles in or out, and 25 where it does both.

A side yard abutting a residence district must match that district's multiple-dwelling side yard.
The 10 ft rear yard grows to 30 ft, or the height of the building if that is greater, where it abuts a residence district.
Nothing may be stored or processed in a required yard except gasoline pumps, identification signs and parking.
An accessory building must stand back from a residence district boundary by at least its own height.
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the commercial buildings on the abutting lots fronting the same street.
No lot coverage or impervious standard is set anywhere in the chapter.

C-2 Commercial - No lot area and no frontage are required of a commercial building here. Side yards are not required either, but any side yard that exists must be at least 5 ft, 12 ft where it carries vehicles in or out, and 25 where it does both.

A side yard abutting a residence district must match that district's multiple-dwelling side yard.
The 10 ft rear yard grows to 30 ft, or the height of the building if that is greater, where it abuts a residence district.
Some uses carry their own distance from a residence boundary: nothing but landscaping or screening within 20 ft for equipment sales and for vehicle service, and 50 ft for animal pens and runways.
On-premises alcohol sales are barred altogether on a lot whose side line abuts a residence district.
Nothing may be stored or processed in a required yard except gasoline pumps, identification signs and parking.
No lot coverage or impervious standard is set anywhere in the chapter.

M-1 Manufacturing - The 10 ft side and rear yards become 50 ft where they abut a residence district boundary, and the 25 ft front yard becomes 50 ft wherever the lot lies opposite a residence district or the front yard is used for off-street parking.

No dwelling of any kind may be built here.
No lot area, no frontage and no coverage standard is set for an industrial use.
Accessory buildings may reach 40 ft here rather than the 12 ft allowed in a residence district, and must stand back from a residence district boundary by at least their own height.
Nothing may be stored or processed in a required yard except gasoline pumps, identification signs and parking.
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the industrial buildings on the abutting lots fronting the same street.
Adult uses need a Town Board special permit and may not stand within a thousand feet of another adult use or a school, or five hundred feet of a residence district.

M-2 Manufacturing - The 10 ft side and rear yards become 75 ft where they abut a residence district boundary, and the 25 ft front yard becomes 50 ft wherever the lot lies opposite a residence district or the front yard is used for off-street parking.

No dwelling of any kind may be built here.
No lot area, no frontage and no coverage standard is set for an industrial use.
Accessory buildings may reach 40 ft here rather than the 12 ft allowed in a residence district, and must stand back from a residence district boundary by at least their own height.
Nothing may be stored or processed in a required yard except gasoline pumps, identification signs and parking.
A lot less than a hundred feet deep need not hold a front yard deeper than the average of the industrial buildings on the abutting lots fronting the same street.

ADUs vs. short-term rentals in West Seneca

Short-term rentals allowed with local rules for Town of West Seneca. Renting a home short term needs a Town permit and licence, under the short-term rental law adopted 2-13-2023. 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 minimum0.18–0.46 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityNational Grid territory.
Zoning codeecode360.com/6844815
Building dept(716) 558-3242

ADU FAQ — West Seneca, NY

Are ADUs allowed in West Seneca, NY?

Town of West Seneca has 13 districts. All districts prohibit ADUs. Check your address with the free ADU checker, or confirm with the building department at (716) 558-3242.

Do I need a special permit for an ADU in West Seneca?

No. No district in Town of West Seneca permits an ADU, so there is no permit to apply for. Codes change, so verify with the building department at (716) 558-3242 before ruling it out.

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

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

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 West Seneca, priced by size.

How we know this

Sections analyzed: § 120-5 · § 120-13 · § 120-14 · §§ 120-16 to 120-18 · § 120-19 (C-1) · § 120-20 (C-2) · § 120-21 (M-1) · § 120-22 (M-2)
Districts confirmed: 13 of 13 — every mapped district.
Last reviewed: 2026-08-06
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 West Seneca: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Erie County · All Erie County towns

ADU information for Town of West Seneca is compiled from the municipal code (last reviewed 2026-08-06) 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) 558-3242 before relying on any answer. Source: the Offsite / Aldo zoning dataset.