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 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 Stillwater maps 11 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 |
|---|---|---|---|---|
| Cold Spring Road Transition Zone (2 ACRES PER DWELLING UNIT — the lowest density in Stillwater — with a 40% maximum lot coverage, 35 ft height, 200 ft of required road frontage, and 50 ft front / 25 ft side / 25 ft rear setbacks. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. CSR is the Town's agricultural-transition district and it carries a setback exemption found nowhere else in Table 2: NOTE 1 PROVIDES THAT THE SETBACK AND WIDTH REQUIREMENTS DO NOT APPLY TO AGRICULTURAL USES AND ROADSIDE STANDS, so a barn, farm structure or farm stand is not held to the 50-25-25 envelope. Agricultural use, livestock keeping, timber harvesting and farm stands are all permitted by right here, and farm worker housing is available by special use permit — one of only three districts (with T2 and T3G-1) where that is true. Single-family, two-family and manufactured homes are permitted by right; multifamily is a special permit. The attached accessory dwelling unit is PERMITTED BY RIGHT.) | 2 ac | 50 / 25 / 25 ft | 35 ft | As of right |
| Saratoga Lake Zone-1 (the Saratoga Lake shoreline district: 15,000 SF PER DWELLING UNIT, 40% maximum lot coverage, and the LOWEST HEIGHT LIMIT IN THE TOWN AT 30 FT — every other Stillwater district allows 35 ft or more, and the five-foot difference is a deliberate lake-view protection. Setbacks are 20 ft front, 15 ft side, 30 ft rear, and required road frontage is only 75 ft. NOTE THE INVERTED SETBACK PATTERN: the REAR yard at 30 ft is deeper than the FRONT at 20 ft, which is the opposite of most districts and reflects lakefront lots where the rear faces the water. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. The use list is deliberately narrow — single-family, two-family, manufactured homes and farm stands by right, bed-and-breakfast and home occupation by special permit, and NO multifamily, no agricultural use, no livestock and no timber harvesting. The attached accessory dwelling unit is PERMITTED BY RIGHT. The SARATOGA LAKE WATERSHED OVERLAY DISTRICT (§ 210-13) sits over this area and imposes watershed protection requirements on top of these figures — check whether a parcel falls inside it before designing anything near the lake.) | 0.34 ac | 20 / 15 / 30 ft | 30 ft | As of right |
| Route 76 Crossroads District (15,000 SF minimum lot — and NOTE THAT THIS IS ONE OF ONLY THREE DISTRICTS WHERE TABLE 2 STATES A FLAT LOT SIZE RATHER THAN A PER-DWELLING-UNIT DENSITY, alongside MB's one acre; read it as a genuine lot minimum. 60% maximum lot coverage, 35 ft height, 30 ft front / 15 ft side / 20 ft rear setbacks, and the SHALLOWEST ROAD FRONTAGE REQUIREMENT IN THE TOWN AT 60 FT alongside T3G's 50 ft. The 60% coverage against a 15,000 sf lot makes this one of the more efficiently buildable districts in Stillwater. Single-family, two-family and manufactured homes are permitted by right and multifamily is a special permit, so the residential range is wide — BUT THE ATTACHED ACCESSORY DWELLING UNIT IS NOT PERMITTED HERE, confirmed 2026-07-31: Table 1 omits it for R76, and an unlisted use is an unavailable one. R76 is the only Stillwater district that permits a principal dwelling by right yet withholds the accessory unit, so the ADU route that exists in eight of the eleven districts is closed on Route 76 land. Agricultural use, livestock, timber harvesting, commercial greenhouse and commercial equestrian use are all available, which is what gives this crossroads district its rural-commercial character.) | 0.34 ac | 30 / 15 / 20 ft | 35 ft | No |
| Mixed-Use Business District (1 ACRE minimum lot — a flat lot standard, not a per-dwelling-unit density — with 60% maximum lot coverage, 200 ft required road frontage, and 50 ft front / 35 ft side / 35 ft rear setbacks. MB SHARES WITH R67 THE TALLEST HEIGHT ALLOWANCE IN STILLWATER AT 50 FT, well above the 35 ft of the conventional districts and the 40 ft of the T4 and T5 transects. THIS IS THE MOST RESIDENTIALLY RESTRICTED DISTRICT IN THE TOWN: single-family, two-family and manufactured homes are ALL PROHIBITED and the only residential use is the MULTIFAMILY DWELLING BY SPECIAL PERMIT. There is consequently no attached accessory dwelling unit, and MB is also the ONLY district where the bed-and-breakfast is unavailable — it is a special permit in all ten others. Timber harvesting and accessory uses incidental to the principal use are permitted; home occupation is a special permit. Treat MB as a commercial district that tolerates apartments above or alongside business use, not as a housing district.) | 1 ac | 50 / 35 / 35 ft | 50 ft | No |
| Route 67 Mixed-Use District (a three-rung UTILITY LADDER on density, the steepest in Stillwater: 3 ACRES PER DWELLING UNIT WITHOUT public water and sewer, 2 ACRES with EITHER, and 1 ACRE with BOTH. The recorded 1 acre is the fully serviced best case and the unserviced figure is three times that — on a Route 67 parcel the question of what is at the street is worth more than any other variable. 40% maximum lot coverage, 50 FT HEIGHT (tied with MB for the tallest in Town), 200 ft required road frontage, and 50 ft front / 35 ft side / 35 ft rear setbacks. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. LIKE MB, R67 PROHIBITS THE SINGLE-FAMILY, TWO-FAMILY AND MANUFACTURED HOME and permits only the MULTIFAMILY DWELLING BY SPECIAL PERMIT — so the per-dwelling-unit density above governs an apartment project, not a subdivision, and there is no principal dwelling for an accessory unit to attach to. Bed-and-breakfast, commercial greenhouse or nursery, farmers' market and home occupation are special permits. Read the acreage and the use table together before assuming R67 land is subdividable — it is not.) | 1 ac | 50 / 35 / 35 ft | 50 ft | No |
| T2 Rural Conservation Transect Zone (the rural end of Stillwater's TRANSECT-BASED code — the Town runs a SmartCode-style T2 through T5 gradient alongside four conventional districts, which is unique in Saratoga County and is the single most distinctive thing about this ordinance. T2 sets 2 ACRES PER DWELLING UNIT WITHOUT public water and sewer, falling to 1.5 ACRES with EITHER OR BOTH — note the ladder collapses to two rungs here rather than the three in R67, T3N and T3G-1, so a second utility adds nothing once the first is present. 40% maximum lot coverage, 200 ft required road frontage, 50 ft front / 25 ft side / 30 ft rear setbacks. HEIGHT IS STATED IN THE TRANSECT FORM — '2 STORIES OR 35 FEET' — so the storey count binds independently of the foot measurement and a low-eaved three-storey design fails even under 35 ft. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. T2 is the Town's working-landscape district: agricultural use, livestock, timber harvesting and farm stands by right, and it is one of only two districts permitting AGRICULTURAL TOURISM (by special use permit) alongside farm worker housing. The attached accessory dwelling unit is PERMITTED BY RIGHT, which on two-acre rural land is the cheapest second unit available in the Town.) | 1.5 ac | 50 / 25 / 30 ft | 35 ft | As of right |
| T3 Neighborhood Transect Zone (the suburban rung of the transect and THE DISTRICT WHERE UTILITY SERVICE MATTERS MOST IN PROPORTIONAL TERMS: 1 ACRE PER DWELLING UNIT WITHOUT public water and sewer, 20,000 SF with EITHER, and 10,000 SF WITH BOTH — a better than fourfold density increase from the unserviced to the fully serviced case. The recorded 0.23 acre is that 10,000 sf best case. 40% maximum lot coverage, 150 ft required road frontage, 35 ft front / 20 ft side / 30 ft rear setbacks, and height stated as 2 STORIES OR 35 FEET, with the storey count binding independently. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. The residential range is the conventional suburban set — single-family, two-family and manufactured homes by right — but MULTIFAMILY IS NOT PERMITTED IN T3N AT ALL, not even by special permit, which distinguishes it from T3G. Agricultural use, livestock and farm stands remain available by right, keeping the district's edge-of-town character. The attached accessory dwelling unit is PERMITTED BY RIGHT. T3N and T3G-1 carry IDENTICAL dimensional standards — see the T3G-1 entry for what separates them.) | 0.23 ac | 35 / 20 / 30 ft | 35 ft | As of right |
| T3 Gateway Transect Zone (the densest of the T3 rungs and a sharp break from its siblings: 6,000 SF PER DWELLING UNIT WITH NO UTILITY LADDER AT ALL — the figure is flat, where T3N and T3G-1 run a three-rung ladder from an acre down to 10,000 sf. At 6,000 sf T3G is denser than the fully serviced T3N standard, and it reaches that without requiring public water or sewer on paper. 60% MAXIMUM LOT COVERAGE against 40% in T2, T3N and T3G-1, 50 ft required road frontage — tied with T4 and T5 for the shallowest in Town — and setbacks of 35 ft front / 15 ft side / 10 FT REAR, the shallowest rear yard of any T3 district. Height is 2 stories or 35 feet, with the storey count binding independently. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. T3G is also the only T3 district permitting MULTIFAMILY (by special permit), and it retains agricultural use, livestock, commercial greenhouse and commercial equestrian use by right or special permit — an unusual combination of near-urban density with working-land uses still on the table. The attached accessory dwelling unit is PERMITTED BY RIGHT. On the numbers this is the most efficient by-right residential district in Stillwater.) | 0.14 ac | 35 / 15 / 10 ft | 35 ft | As of right |
| T3G-1 Rural Gateway Transect Zone (DIMENSIONALLY IDENTICAL TO T3N IN EVERY FIGURE — 1 acre per dwelling unit without public water and sewer, 20,000 SF with either, 10,000 SF with both, 40% maximum lot coverage, 150 ft required road frontage, 35 ft front / 20 ft side / 30 ft rear, and 2 stories or 35 feet — despite carrying the Gateway name and sitting beside T3G, which is materially denser at a flat 6,000 sf and 60% coverage. THE NAME IS MISLEADING: T3G-1 is a rural-gateway zone that follows the T3N standard, not the T3G one. Anyone reading the district code as a variant of T3G will overstate density by roughly 60% and coverage by half. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. What distinguishes T3G-1 from T3N is the use list rather than the dimensions: T3G-1 permits FARM WORKER HOUSING by special use permit (one of only three districts, with CSR and T2) and permits commercial equestrian use, neither of which T3N allows, while both exclude multifamily entirely. The attached accessory dwelling unit is PERMITTED BY RIGHT.) | 0.23 ac | 35 / 20 / 30 ft | 35 ft | As of right |
| T4 Riverfront Corridor Transect Zone (the Hudson riverfront district and the first rung of the transect to reach genuinely urban form: 6,000 SF PER DWELLING UNIT flat with no utility ladder, 60% maximum lot coverage, 50 ft required road frontage, and setbacks of 15 FT FRONT / 15 ft side / 10 ft rear — the front yard drops to a quarter of what T2 requires and half of T3N's. HEIGHT RISES TO 3 STORIES OR 40 FEET, the tallest of the transect zones and above every conventional district except MB and R67 at 50 ft; as elsewhere in the transect the storey count binds independently of the foot measure, so a three-storey building is the ceiling regardless of how far under 40 ft it comes in. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. MULTIFAMILY IS AVAILABLE BY SPECIAL PERMIT alongside single-family, two-family and manufactured homes by right, and the attached accessory dwelling unit is PERMITTED BY RIGHT — so T4 offers the widest housing-type range in the Town on the second-smallest lot standard. Farm stands and accessory uses remain permitted, but livestock, timber harvesting and commercial equestrian use drop away at this rung. The Route 4 Corridor Design Guidelines (March 2017, an attachment to Chapter 210) apply along the corridor and will shape façade and frontage treatment beyond these figures.) | 0.14 ac | 15 / 15 / 10 ft | 40 ft | As of right |
| T5 Gateway Transect Zone (the urban core of the transect and the densest district in Stillwater: 5,000 SF PER DWELLING UNIT, 75% MAXIMUM LOT COVERAGE — the highest in the Town by fifteen points — 50 ft required road frontage, and 3 stories or 40 feet in height with the storey count binding independently. THE SETBACKS ARE STATED AS RANGES STARTING AT ZERO, WHICH IS THE POINT OF THE DISTRICT: the front setback is '0 TO 10 FEET, OR 15 FEET WITH OUTDOOR DINING OR A PLAZA' and the side is '0 TO 5 FEET', with a 5 ft rear. Both are recorded at their zero floor because zero is genuinely permitted — this is party-wall, build-to-the-sidewalk urbanism, and the upper end of each range is an allowance rather than a requirement. The explicit fifteen-foot option purchased by providing outdoor dining or a plaza is a rare piece of incentive zoning in this county and is worth using deliberately rather than treating as a maximum to avoid. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. Multifamily is available by special permit and the attached accessory dwelling unit is PERMITTED BY RIGHT, though at 5,000 sf per unit with 75% coverage the multifamily route will usually dominate. Agricultural uses, livestock, farm stands and timber harvesting all drop away entirely at this rung — T5 is the only Stillwater district with no working-land use of any kind.) | 0.11 ac | 0 / 0 / 5 ft | 40 ft | As of right |
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Size limits on record in Stillwater
Where the code states a size cap, it decides which row of the cost table above actually applies to you. These are the caps recorded for Stillwater:
- Cold Spring Road Transition Zone (2 ACRES PER DWELLING UNIT — the lowest density in Stillwater — with a 40% maximum lot coverage, 35 ft height, 200 ft of required road frontage, and 50 ft front / 25 ft side / 25 ft rear setbacks. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. CSR is the Town's agricultural-transition district and it carries a setback exemption found nowhere else in Table 2: NOTE 1 PROVIDES THAT THE SETBACK AND WIDTH REQUIREMENTS DO NOT APPLY TO AGRICULTURAL USES AND ROADSIDE STANDS, so a barn, farm structure or farm stand is not held to the 50-25-25 envelope. Agricultural use, livestock keeping, timber harvesting and farm stands are all permitted by right here, and farm worker housing is available by special use permit — one of only three districts (with T2 and T3G-1) where that is true. Single-family, two-family and manufactured homes are permitted by right; multifamily is a special permit. The attached accessory dwelling unit is PERMITTED BY RIGHT.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- Saratoga Lake Zone-1 (the Saratoga Lake shoreline district: 15,000 SF PER DWELLING UNIT, 40% maximum lot coverage, and the LOWEST HEIGHT LIMIT IN THE TOWN AT 30 FT — every other Stillwater district allows 35 ft or more, and the five-foot difference is a deliberate lake-view protection. Setbacks are 20 ft front, 15 ft side, 30 ft rear, and required road frontage is only 75 ft. NOTE THE INVERTED SETBACK PATTERN: the REAR yard at 30 ft is deeper than the FRONT at 20 ft, which is the opposite of most districts and reflects lakefront lots where the rear faces the water. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. The use list is deliberately narrow — single-family, two-family, manufactured homes and farm stands by right, bed-and-breakfast and home occupation by special permit, and NO multifamily, no agricultural use, no livestock and no timber harvesting. The attached accessory dwelling unit is PERMITTED BY RIGHT. The SARATOGA LAKE WATERSHED OVERLAY DISTRICT (§ 210-13) sits over this area and imposes watershed protection requirements on top of these figures — check whether a parcel falls inside it before designing anything near the lake.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T2 Rural Conservation Transect Zone (the rural end of Stillwater's TRANSECT-BASED code — the Town runs a SmartCode-style T2 through T5 gradient alongside four conventional districts, which is unique in Saratoga County and is the single most distinctive thing about this ordinance. T2 sets 2 ACRES PER DWELLING UNIT WITHOUT public water and sewer, falling to 1.5 ACRES with EITHER OR BOTH — note the ladder collapses to two rungs here rather than the three in R67, T3N and T3G-1, so a second utility adds nothing once the first is present. 40% maximum lot coverage, 200 ft required road frontage, 50 ft front / 25 ft side / 30 ft rear setbacks. HEIGHT IS STATED IN THE TRANSECT FORM — '2 STORIES OR 35 FEET' — so the storey count binds independently of the foot measurement and a low-eaved three-storey design fails even under 35 ft. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. T2 is the Town's working-landscape district: agricultural use, livestock, timber harvesting and farm stands by right, and it is one of only two districts permitting AGRICULTURAL TOURISM (by special use permit) alongside farm worker housing. The attached accessory dwelling unit is PERMITTED BY RIGHT, which on two-acre rural land is the cheapest second unit available in the Town.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T3 Neighborhood Transect Zone (the suburban rung of the transect and THE DISTRICT WHERE UTILITY SERVICE MATTERS MOST IN PROPORTIONAL TERMS: 1 ACRE PER DWELLING UNIT WITHOUT public water and sewer, 20,000 SF with EITHER, and 10,000 SF WITH BOTH — a better than fourfold density increase from the unserviced to the fully serviced case. The recorded 0.23 acre is that 10,000 sf best case. 40% maximum lot coverage, 150 ft required road frontage, 35 ft front / 20 ft side / 30 ft rear setbacks, and height stated as 2 STORIES OR 35 FEET, with the storey count binding independently. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. The residential range is the conventional suburban set — single-family, two-family and manufactured homes by right — but MULTIFAMILY IS NOT PERMITTED IN T3N AT ALL, not even by special permit, which distinguishes it from T3G. Agricultural use, livestock and farm stands remain available by right, keeping the district's edge-of-town character. The attached accessory dwelling unit is PERMITTED BY RIGHT. T3N and T3G-1 carry IDENTICAL dimensional standards — see the T3G-1 entry for what separates them.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T3 Gateway Transect Zone (the densest of the T3 rungs and a sharp break from its siblings: 6,000 SF PER DWELLING UNIT WITH NO UTILITY LADDER AT ALL — the figure is flat, where T3N and T3G-1 run a three-rung ladder from an acre down to 10,000 sf. At 6,000 sf T3G is denser than the fully serviced T3N standard, and it reaches that without requiring public water or sewer on paper. 60% MAXIMUM LOT COVERAGE against 40% in T2, T3N and T3G-1, 50 ft required road frontage — tied with T4 and T5 for the shallowest in Town — and setbacks of 35 ft front / 15 ft side / 10 FT REAR, the shallowest rear yard of any T3 district. Height is 2 stories or 35 feet, with the storey count binding independently. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. T3G is also the only T3 district permitting MULTIFAMILY (by special permit), and it retains agricultural use, livestock, commercial greenhouse and commercial equestrian use by right or special permit — an unusual combination of near-urban density with working-land uses still on the table. The attached accessory dwelling unit is PERMITTED BY RIGHT. On the numbers this is the most efficient by-right residential district in Stillwater.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T3G-1 Rural Gateway Transect Zone (DIMENSIONALLY IDENTICAL TO T3N IN EVERY FIGURE — 1 acre per dwelling unit without public water and sewer, 20,000 SF with either, 10,000 SF with both, 40% maximum lot coverage, 150 ft required road frontage, 35 ft front / 20 ft side / 30 ft rear, and 2 stories or 35 feet — despite carrying the Gateway name and sitting beside T3G, which is materially denser at a flat 6,000 sf and 60% coverage. THE NAME IS MISLEADING: T3G-1 is a rural-gateway zone that follows the T3N standard, not the T3G one. Anyone reading the district code as a variant of T3G will overstate density by roughly 60% and coverage by half. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. What distinguishes T3G-1 from T3N is the use list rather than the dimensions: T3G-1 permits FARM WORKER HOUSING by special use permit (one of only three districts, with CSR and T2) and permits commercial equestrian use, neither of which T3N allows, while both exclude multifamily entirely. The attached accessory dwelling unit is PERMITTED BY RIGHT.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T4 Riverfront Corridor Transect Zone (the Hudson riverfront district and the first rung of the transect to reach genuinely urban form: 6,000 SF PER DWELLING UNIT flat with no utility ladder, 60% maximum lot coverage, 50 ft required road frontage, and setbacks of 15 FT FRONT / 15 ft side / 10 ft rear — the front yard drops to a quarter of what T2 requires and half of T3N's. HEIGHT RISES TO 3 STORIES OR 40 FEET, the tallest of the transect zones and above every conventional district except MB and R67 at 50 ft; as elsewhere in the transect the storey count binds independently of the foot measure, so a three-storey building is the ceiling regardless of how far under 40 ft it comes in. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. MULTIFAMILY IS AVAILABLE BY SPECIAL PERMIT alongside single-family, two-family and manufactured homes by right, and the attached accessory dwelling unit is PERMITTED BY RIGHT — so T4 offers the widest housing-type range in the Town on the second-smallest lot standard. Farm stands and accessory uses remain permitted, but livestock, timber harvesting and commercial equestrian use drop away at this rung. The Route 4 Corridor Design Guidelines (March 2017, an attachment to Chapter 210) apply along the corridor and will shape façade and frontage treatment beyond these figures.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
- T5 Gateway Transect Zone (the urban core of the transect and the densest district in Stillwater: 5,000 SF PER DWELLING UNIT, 75% MAXIMUM LOT COVERAGE — the highest in the Town by fifteen points — 50 ft required road frontage, and 3 stories or 40 feet in height with the storey count binding independently. THE SETBACKS ARE STATED AS RANGES STARTING AT ZERO, WHICH IS THE POINT OF THE DISTRICT: the front setback is '0 TO 10 FEET, OR 15 FEET WITH OUTDOOR DINING OR A PLAZA' and the side is '0 TO 5 FEET', with a 5 ft rear. Both are recorded at their zero floor because zero is genuinely permitted — this is party-wall, build-to-the-sidewalk urbanism, and the upper end of each range is an allowance rather than a requirement. The explicit fifteen-foot option purchased by providing outdoor dining or a plaza is a rare piece of incentive zoning in this county and is worth using deliberately rather than treating as a maximum to avoid. MINIMUM LOT SIZE IN STILLWATER IS STATED PER DWELLING UNIT, NOT PER LOT. Table 2's column reads 'Minimum Lot Size' but nearly every entry is expressed 'per dwelling unit', which makes it a density standard: a two-unit building needs twice the figure. Read it as density and not as the size of a buildable lot. Multifamily is available by special permit and the attached accessory dwelling unit is PERMITTED BY RIGHT, though at 5,000 sf per unit with 75% coverage the multifamily route will usually dominate. Agricultural uses, livestock, farm stands and timber harvesting all drop away entirely at this rung — T5 is the only Stillwater district with no working-land use of any kind.)Compare Ballston, whose interior ADU is also by right but which allows a detached 1,000 sq ft version by special permit — Stillwater is broader by right, Ballston more flexible in form
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 Town of Stillwater Zoning Law. Chapter 210 was read in full: § 210-7 Definitions contains no short-term rental, vacation rental or transient-occupancy term (the phrase 'short-term' appears only in the nonconforming-use section, describing short-term interruptions to a use during remodelling or seasonal closure), Table 1 Summary of Allowed Uses lists no such use, and there is no registration or licensing requirement anywhere in the chapter. The only enumerated transient-lodging use is the BED-AND-BREAKFAST, which is a SPECIAL PERMIT in ten of the eleven districts — every district except the Mixed-Use Business District, where it is prohibited outright. That near-universal availability by special permit is the Town's stated position on short-stay lodging, and it is a permit-gated, owner-present use rather than a whole-house short-term rental. Recorded 'unknown' rather than 'prohibited' because the Town has never legislated on short-term rental specifically. Absence of a found STR provision is NOT permission. This matters more than usual in Stillwater because of Saratoga Lake and the Hudson riverfront, where short-term rental demand is real and the Town has not yet addressed it — get a written answer from the Building Department at (518) 664-6148 x215 before underwriting short-term rental income, and note that a Saratoga Lake parcel may also sit inside the Saratoga Lake Watershed Overlay District. 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) 664-6148 x215
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 $1,493 for a conforming lot. See what it costs to build a house in Stillwater.
ADU cost in nearby towns
Mechanicville (City)
800 sq ft ≈ $200k–260k
Saratoga Springs (City)
800 sq ft ≈ $200k–260k
Ballston
800 sq ft ≈ $200k–260k
Charlton
800 sq ft ≈ $200k–260k
Clifton Park
800 sq ft ≈ $200k–260k
Corinth
800 sq ft ≈ $200k–260k
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 · Waterford · Wilton · Ballston Spa (Village) · Corinth (Village) · Round Lake (Village) · Schuylerville (Village) · South Glens Falls (Village) · Stillwater (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 Town 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?
Town of Stillwater has 11 districts. 8 districts allow ADUs, 3 do not. Check the specific address with the free ADU checker or confirm with the building department at (518) 664-6148 x215 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 Town 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 Town of Stillwater vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-07-31; verify with the building department at (518) 664-6148 x215 before relying on any answer. Sources: Offsite / Aldo cost engine (costEngine.js + constants.js); zoning dataset (municipalData.js).