Sweden · ADU cost
What it costs to build an ADU in Sweden, NY
An 800 sq ft accessory dwelling unit in Sweden 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 town 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 Town of Sweden maps 4 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 Sweden
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Monroe 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 Sweden 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 |
|---|---|---|---|---|
| One-Family Residential, no sewer and/or water | 1.84 ac | 75 / 10 / 40 ft | 36 ft | No |
| One-Family Residential within a sanitary sewer district | 0.34 ac | 50 / 10 / 40 ft | 36 ft | No |
| One-Family Residential within a sanitary sewer district | 0.23 ac | 40 / 10 / 40 ft | 36 ft | No |
| Multiple Residence | — | 20 / 20 / 50 ft | 36 ft | No |
One-Family Residential, no sewer and/or water - The lot minimum turns on septic and water: 40,000 sq ft with public water and an in-ground or modified raised fill system, 150,000 sq ft where an aboveground modified raised fill system is needed, and five acres where a full raised fill system is required.
- Lot area is net: it excludes designated wetlands and their one-hundred-foot buffers, highway rights-of-way, reserved strips and the driveway land on a flag lot (§ 175-36D(2)(d)).
- The 40,000 sq ft step takes 150 ft of width, and the 150,000 sq ft and five-acre steps take 260 ft.
- Road frontage stays 60 ft at every step, and width is measured at the front line of the house, so a lot may neck down at the road if it opens to the required width where the house sits.
- An aboveground modified raised fill system has its own setbacks: 75 ft to the sides and 50 ft front and rear on a 150,000 sq ft lot, and 25 ft to every property line on a 40,000 sq ft lot.
- Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
- Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.
One-Family Residential within a sanitary sewer district - This district is mapped as a sanitary sewer district, so whether a parcel is here or in R1-2 comes from the Zoning Map, not from whether the lot is connected. The same one-family house needs 15,000 sq ft here and 80,000 sq ft in R1-2.
- On an arterial highway the front setback rises to 75 ft.
- Width is measured at the front line of the house, and only 60 ft of road frontage is required.
- Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
- Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.
One-Family Residential within a sanitary sewer district - Every property line that abuts a street must meet the front setback, so a corner lot owes 40 ft on both frontages. On an arterial highway the front setback rises to 75 ft.
- Lot depth may be reduced by up to 10%, to 108 ft, provided the minimum lot area is still maintained.
- Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
- Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.
Multiple Residence - At least 25% of the total lot area must stay open and unused, and it may not be paved or used for parking, storage or buildings. Parking is not counted in the 50% building coverage, so the site plan splits three ways between building, parking and open space.
- The district states no minimum lot area, so yield comes from the 12 units per acre density cap and the 50% coverage cap together.
- Parking is two spaces per apartment in buildings over four units, and three per unit for town homes, patio homes, condominiums, duplexes and quadplexes, at least one in an enclosed garage.
- Buildings on the same site must stand 20 ft apart.
- The open area may include landscaping, stormwater retention or detention, underground utilities, screening and fencing.
- Multiple dwellings, town homes, patio homes, condominiums and zero lot-line duplexes and quadplexes are permitted by right.
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 RG&E 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 Town of Sweden Code has no short-term rental provision, and each district's principal uses are a closed list, so a short-term rental may be an unpermitted use. The rule is not confirmed; confirm with the building department before counting on the use. Separate question from whether you can build the unit.
- Zoning codeecode360.com/10495462
- Building dept(585) 637-8684
Sizing up a specific parcel in Sweden?
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 Sweden runs $204–268/sq ft, about $370k–480k at 1,800 sq ft , plus roughly $1,520 for a conforming lot. See what it costs to build a house in Sweden.
ADU cost in nearby towns
All Monroe County towns: Rochester (City) · Brighton · Chili · Clarkson · Gates · Greece · Hamlin · Henrietta · Irondequoit · Mendon · Ogden · Parma · Penfield · Perinton · Pittsford · Riga · Rush · Webster · Wheatland · East Rochester (Village) · Brockport (Village) · Churchville (Village) · Fairport (Village) · Hilton (Village) · Honeoye Falls (Village) · Pittsford (Village) · Scottsville (Village) · Spencerport (Village) · Webster (Village)
More on Sweden: Can you build an ADU here? · Zoning for new construction · Monroe County build cost
ADU cost in Sweden: common questions
How much does it cost to build an ADU in Sweden, NY?
An 800 sq ft accessory dwelling unit in Town of Sweden 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 Sweden?
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 Sweden?
Town of Sweden has 4 districts. All districts prohibit ADUs. Check the specific address with the free ADU checker or confirm with the building department at (585) 637-8684 before you spend money on design.
Can I rent an ADU in Sweden short term?
No local short-term-rental law on record - which is not the same as permission for Town of Sweden. 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 Monroe 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 Town of Sweden vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-08-13; verify with the building department at (585) 637-8684 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.