Stillwater · ADU cost
What it costs to build an ADU in Stillwater, NY
An 800 sq ft accessory dwelling unit in Stillwater 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 Stillwater maps 3 districts that treat accessory units differently from one another, so read the table below as a starting point rather than a verdict.
ADU cost by size in Stillwater
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Saratoga 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 Stillwater 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 |
|---|---|---|---|---|
| V3 Neighborhood (the Village's residential transect and its most conventional zone: a 10,000 SQ FT minimum lot — double either mixed-use zone's — with a 40 ft minimum lot width, a 15 ft front setback, 10 ft side and 20 FT REAR yards, 60% maximum coverage and a 2-STORY OR 35 FT height cap. Its yards are the deepest in the Village and its coverage the lowest; V3 is where the code stops being urban. V3 is also the only zone permitting AGRICULTURAL AND AGRICULTURAL TOURISM USE and roadside farm stands by right, and the only one where a MANUFACTURED HOME OR MANUFACTURED HOME PARK, a CEMETERY or a SELF-STORAGE FACILITY is available at all, each by special use permit. Marinas and other waterfront-related uses are a site-plan use here as in V4. ) | 0.23 ac | 15 / 10 / 20 ft | 35 ft | Occupancy restricted |
| V4 Mixed Use (the Hudson-facing mixed-use transect: a 5,000 SQ FT minimum lot, 30 ft minimum lot width, a 0-10 FT front setback (or 15 ft where the extra depth is used for OUTDOOR DINING OR A PLAZA), a 5 ft rear yard and 75% maximum coverage. BUILD-TO, NOT SET-BACK: § 4.3A says buildings are PREFERRED TO BE BUILT TO THE SIDEWALK in the V4 and V5 zones, or a maximum of 10 FEET from the frontage line — the '0-10 ft' front figure is a BAND with a MAXIMUM, not a minimum, and the only way past 10 ft is the 15 ft permitted expressly for OUTDOOR DINING OR A PLAZA. Pushing a building back is a violation here, not a courtesy. § 4.3B(1) also provides that there is NO SIDE YARD SETBACK AT ALL for buildings that share a party wall. THE USE LIST OPENS UP SHARPLY FROM V3: ONE-FAMILY, TWO-FAMILY AND ACCESSORY DWELLING UNITS ARE ALL PERMITTED BY RIGHT, and three- and four-family dwellings, MULTIFAMILY OF FIVE OR MORE, assisted living, mixed-use buildings, LIVE-WORK units, offices, retail, restaurants, banks, hotels, motels and inns are all available by SITE PLAN REVIEW rather than special use permit — a materially lower bar than most of this county applies to the same uses. Craft production, light industrial, drive-through windows and fast-food restaurants need a special use permit. ) | 0.11 ac | 0 / 5 / 5 ft | 40 ft | Occupancy restricted |
| V5 Mixed Use Center (the Village core and its densest zone: a 5,000 SQ FT minimum lot, 30 ft minimum lot width, a 0-10 FT front setback (15 ft for outdoor dining or a plaza), 5 ft side and rear yards, AN 80% MAXIMUM COVERAGE — the highest in the Village — and 3 STORIES OR 40 FT of height. BUILD-TO, NOT SET-BACK: § 4.3A says buildings are PREFERRED TO BE BUILT TO THE SIDEWALK in the V4 and V5 zones, or a maximum of 10 FEET from the frontage line — the '0-10 ft' front figure is a BAND with a MAXIMUM, not a minimum, and the only way past 10 ft is the 15 ft permitted expressly for OUTDOOR DINING OR A PLAZA. Pushing a building back is a violation here, not a courtesy. § 4.3B(1) also provides that there is NO SIDE YARD SETBACK AT ALL for buildings that share a party wall. Uses match V4 with additions: ADULT USE, AUTO SALES, CAR WASH and a VEHICLE SERVICE STATION are available here by special use permit and nowhere else. ONE-FAMILY, TWO-FAMILY AND ACCESSORY DWELLING UNITS ARE PERMITTED BY RIGHT; multifamily of five or more, mixed-use buildings and live-work are site-plan uses. ) | 0.11 ac | 0 / 5 / 5 ft | 40 ft | Occupancy restricted |
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. NO SHORT-TERM-RENTAL PROVISION EXISTS IN THE VILLAGE OF STILLWATER FORM-BASED CODE. A full-text read of the 92-page document returns no 'short-term rental' and no 'vacation rental', and Table 1's Lodging block runs only Bed & Breakfast, Hotel or Motel, and Inn. Recorded 'unknown' rather than 'prohibited': whole-house rental of a permitted dwelling is arguably the residential use itself, and absence of a found provision is NOT permission. SMALL-SCALE RECEPTIONS OR SIMILAR GATHERINGS MAY BE HELD INCIDENTALLY to the primary bed-and-breakfast inn use, subject to the site's size, traffic level, parking count, proximity to adjoining residences and number of restrooms, and confined to the vicinity of the inn — an events allowance most codes of this size do not give at all, and a real revenue line on a Hudson-side property. The bed and breakfast is a SITE PLAN use in all three transect zones (V3, V4 and V5), and a HOTEL, MOTEL or INN is a site plan use in V4 and V5. Get a written answer from the Village office at (518) 664-6258 before underwriting short-term rental income, and expect the owner-residence logic of § 3.5 to be the lens applied. Separately, New York State has required every short-term-rental host to register the unit with the State through the county registry since 2025 regardless of what the municipality allows, and Saratoga County HAS adopted a county-level short-term-rental programme: a 3% occupancy tax and a MANDATORY county registry, covering any room or space in a dwelling let for under 30 consecutive days. Registration runs two years, an unregistered host faces fines of up to $500, and the booking platform is separately liable for processing an unregistered listing — so Airbnb and Vrbo will delist. The City of Saratoga Springs runs its own registry alongside it. Separate question from whether you can build the unit.
- Building dept(518) 664-6258
Sizing up a specific parcel in Stillwater?
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 Stillwater runs $204–268/sq ft, about $370k–480k at 1,800 sq ft , plus roughly $727 for a conforming lot. See what it costs to build a house in Stillwater.
ADU cost in nearby towns
All Saratoga County towns: Mechanicville (City) · Saratoga Springs (City) · Ballston · Charlton · Clifton Park · Corinth · Day · Edinburg · Galway · Greenfield · Halfmoon · Malta · Milton · Moreau · Northumberland · Providence · Saratoga · Stillwater · Waterford · Wilton · Ballston Spa (Village) · Corinth (Village) · Round Lake (Village) · Schuylerville (Village) · South Glens Falls (Village) · Victory (Village) · Waterford (Village)
More on Stillwater: Can you build an ADU here? · Zoning for new construction · Saratoga County build cost
ADU cost in Stillwater: common questions
How much does it cost to build an ADU in Stillwater, NY?
An 800 sq ft accessory dwelling unit in Village of Stillwater 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 Stillwater?
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 Stillwater?
Village of Stillwater has 3 districts. All districts allow ADUs with occupancy restrictions. Check the specific address with the free ADU checker or confirm with the building department at (518) 664-6258 before you spend money on design.
Can I rent an ADU in Stillwater short term?
No local short-term-rental law on record - which is not the same as permission for Village of Stillwater. 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 Saratoga 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 Stillwater vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-08-02; verify with the building department at (518) 664-6258 before relying on any answer. Sources: Offsite / Aldo cost engine (costEngine.js + constants.js); zoning dataset (municipalData.js).