Depew · ADU cost
What it costs to build an ADU in Depew, NY
An 800 sq ft accessory dwelling unit in Depew runs roughly $200k–260k, or about $249–327/sq ft, and that per-square-foot figure sits deliberately above the $204–268/sq ft a full house costs here. An ADU still needs one whole kitchen, one whole bath, its own service panel and its own heating plant no matter how small you draw it, and those costs do not shrink with the floor plan, so they land on half the square footage and push the rate up. Whether the village will let you build one is a separate question from what it costs, and it gets answered parcel by parcel rather than townwide, since the Village of Depew maps 8 districts that treat accessory units differently from one another, so read the table below as a starting point rather than a verdict.
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ADU cost by size in Depew
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Erie County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $331–$433 | $130k–175k |
| 600 sq ft | One bedroom | $276–$362 | $165k–215k |
| 800 sq ft | One bedroom, larger | $249–$327 | $200k–260k |
| 1,000 sq ft | Two bedroom | $233–$305 | $235k–305k |
400 sq ft — One room plus a bath. Garage conversions and small backyard cottages land here.
600 sq ft — The most common detached build - a real bedroom, full kitchen, one bath.
800 sq ft — Room for a proper living area. Still a single bath and one kitchen.
1,000 sq ft — About as large as most codes allow an accessory unit to go.
Why the rate is higher than a house
The systems below are priced for an 800 sq ft unit. The middle column is what each system would cost if it simply shrank with the floor plan; the left column is what it actually costs once you account for the equipment a dwelling needs one of regardless of size. The gap between the two columns is the whole reason small builds price the way they do.
| System | $ / sq ft in an ADU | If it scaled with floor area | Fixed per unit |
|---|---|---|---|
| Site work | $7–$11 | $7 | — |
| Foundation | $16–$23 | $16 | — |
| Framing | $25–$32 | $25 | — |
| Envelope - roof, siding, windows | $32–$41 | $32 | — |
| Plumbing | $28–$34 | $16 | 55% |
| Electrical | $18–$24 | $13 | 35% |
| HVAC | $23–$28 | $15 | 45% |
| Insulation | $7–$9 | $7 | — |
| Interior finishes | $32–$43 | $27 | 15% |
| Millwork & cabinetry | $18–$28 | $11 | 55% |
The fixed-per-unit share is a modeling assumption, not a figure from the code: it is our estimate of how much of each system's budget buys equipment a dwelling needs exactly one of - a kitchen rough-in, a bath group, a service panel, a heating plant - and therefore does not shrink when the unit does. Site work, foundation, framing, envelope and insulation are treated as scaling straight with floor area, which understates the premium slightly, because a small building carries more envelope per square foot of floor than a large one.
What the Depew code says about accessory units
Whether you can build one, and how large, is decided by the district your parcel sits in rather than by the town as a whole. The table shows how each mapped district treats ADUs alongside the lot and setback standards a second unit still has to fit inside. District boundaries and conditions vary, so treat it 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 Residential District | 0.15 ac | 25 / 6 / 25 ft | 30 ft | Occupancy restricted |
| Two-Family and Multifamily Residential District | 0.15 ac | 25 / 6 / 25 ft | 30 ft | Special permit |
| General Commercial District | 0.14 ac | 30 / 0 / 10 ft | 30 ft | No |
| Shopping Center District | 0.23 ac | 30 / 10 / 10 ft | 30 ft | No |
| Motor Services District | 0.5 ac | 30 / 10 / 10 ft | 30 ft | No |
| Light Industry District | 0.23 ac | 30 / 10 / 10 ft | 30 ft | No |
| Heavy Industry District | 0.23 ac | 30 / 10 / 10 ft | 30 ft | No |
| Land Conservation District | — | — | — | No |
Single-Family Residential District - A corner lot is priced higher than an interior one: 8,400 sq ft on a 75 ft width rather than 6,600 sq ft on 60 ft. A house of more than one storey needs 1,200 sq ft rather than 900.
- Six feet is the least either side yard may be, and the two together must add to 12 ft
- The lot area is stated per dwelling
- A patio home and a zero lot line home carry their own standards under § 260-31 and override these figures, both on 5,000 sq ft and a 40 ft width with no side yard and a 40% coverage cap
- A patio home takes a 12 ft front yard, a 1,000 sq ft walled patio and a 28 ft height cap; a zero lot line home takes a 15 ft front yard and sits against one side line
- Under either form buildings stand 12 ft apart and a garage must sit 20 ft back from the street line
- Confirm with the village which districts permit a patio home or a zero lot line home before relying on the smaller lot
Two-Family and Multifamily Residential District - The figures shown are the single-family standard. A duplex needs 7,500 sq ft, or 10,000 sq ft on a corner, on a 75 ft width with 30 ft front and rear yards and a looser 40% coverage cap.
- Multifamily needs a full acre on a 100 ft width and 150 ft of depth with 30 ft yards all round
- The multifamily corner-lot figure reads 3,500 sq ft minimum per unit, a per-unit density where a corner-lot area should be; confirm it with the village before relying on it
- The multifamily standard also states a 30 ft each-side yard against a 15 ft combined total, which cannot both be minimums; confirm with the village
- A corner lot is priced higher than an interior one: 8,400 sq ft on a 75 ft width rather than 6,600 sq ft on 60 ft
- A house of more than one storey needs 1,200 sq ft rather than 900
- A patio home or a zero lot line home carries its own standards under § 260-31, on 5,000 sq ft and a 40 ft width with a 40% coverage cap; confirm with the village which districts permit them
General Commercial District - The side and rear yards shown apply against another non-residential lot. Against a residential district the side yard is 50 ft and the rear yard is 25 ft or the height of the building, whichever is greater.
- No side yard at all is required against another non-residential lot
- Vehicle use areas take their own setbacks: 15 ft at the front, 20 ft from a residential side or rear line and 10 ft otherwise
- No separation is required between buildings on the same site
Shopping Center District - The side and rear yards shown apply against another non-residential lot. Against a residential district the side yard is 50 ft and the rear yard is 25 ft or the height of the building, whichever is greater.
- Vehicle use areas stand 10 ft back at the front, 20 ft from a residential side or rear line and 10 ft otherwise
- No separation is required between buildings on the same site
Motor Services District - Against a residential district both the side and the rear yard rise to 50 ft, against the 10 ft shown.
- Vehicle use areas stand 15 ft back at the front, 25 ft from a residential side or rear line and 10 ft otherwise
Light Industry District, Heavy Industry District - The side and rear yards shown apply against another non-residential lot. Against a residential district the side yard is 50 ft and the rear yard is 25 ft or the height of the building, whichever is greater.
- Vehicle use areas take their own setbacks: 10 ft at the front, 20 ft from a residential side or rear line and 10 ft otherwise
- No separation is required between buildings on the same site
Land Conservation District - The district exists to prohibit substantial development in the form of buildings or structures, given special or unusual conditions of topography, drainage, floodplain or other natural conditions.
- The code calls L-C both an overlay district and one of the eight districts the Zoning Map establishes, so confirm with the Village whether a parcel carries L-C alone or L-C over a base district
- The general standards for off-street parking, loading and stacking, landscaping, buffers and screening, site lighting, and fences and walls still apply
Costs an ADU adds that a house does not
- Septic and water A second dwelling adds bedrooms to the design flow, which on an unsewered parcel often means expanding or replacing the existing system rather than tapping it. This is the single most common reason an ADU budget moves after design, and it is site-specific enough that no model should quote it - get it evaluated early.
- Utility service National Grid territory. A detached unit needs power run to it, and whether it goes on its own meter or subfeeds the main house changes both the cost and the permit path.
- Access and parking Many codes require an added parking space for the accessory unit, and a detached unit usually needs a driveway extension or a path, both of which count against a lot-coverage or impervious-surface cap.
- Short-term rentalsNo local short-term-rental law on record - which is not the same as permission. The village has no local short-term rental law. That is not the same as permission, so confirm with the village before counting on renting a home short term. Separate question from whether you can build the unit.
- Zoning codeecode360.com/13280870
- Building dept(716) 683-1400
Sizing up a specific parcel in Depew?
Aldo pulls the exact zoning district, setbacks, and build feasibility for any parcel — before you buy. Enter your email to open Aldo and run your free report.
Building a full house instead?
A standard-finish house in Depew runs $204–268/sq ft, about $370k–480k at 1,800 sq ft , plus roughly $11,653 for a conforming lot. See what it costs to build a house in Depew.
ADU cost in nearby towns
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More on Depew: Can you build an ADU here? · Zoning for new construction · Erie County build cost
ADU cost in Depew: common questions
How much does it cost to build an ADU in Depew, NY?
An 800 sq ft accessory dwelling unit in Village of Depew runs roughly $200k–260k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $130k–175k. Those are structure costs on an easy site and do not include the septic, water or electrical service work a second unit often triggers.
Why does an ADU cost more per square foot than a house in Depew?
Because a lot of a dwelling's cost is per dwelling, not per square foot. One kitchen, one bath group, one service panel and one heating plant cost about the same in an 800 sq ft cottage as in a 1,800 sq ft house, so on the smaller unit they get spread over less than half the floor area. That is why an ADU here prices at $249–327/sq ft against $204–268/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Depew?
Village of Depew has 8 districts. 6 districts prohibit ADUs, 1 allows them with occupancy restrictions, 1 requires a special-use permit. Check the specific address with the free ADU checker or confirm with the building department at (716) 683-1400 before you spend money on design.
Can I rent an ADU in Depew short term?
No local short-term-rental law on record - which is not the same as permission for Village of Depew. ADU rules and short-term-rental rules are set separately, so a unit you are allowed to build is not automatically one you are allowed to rent nightly. Confirm both before you underwrite the build on short-term-rental income.
ADU costs are modeled estimates in current 2026 dollars at the Erie County regional index, general-contractor margin included, derived from Offsite's cost engine with a stated adjustment for the equipment a dwelling needs one of regardless of size. They are planning numbers for decision-support only - not a bid, quote, or guarantee, and not legal, architectural or engineering advice. They cover the structure and exclude septic expansion, utility service runs, site work beyond a flat and clear pad, and permit fees. ADU eligibility, size, owner-occupancy and permit conditions in the Village of Depew vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-09-10; verify with the building department at (716) 683-1400 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.