Round Lake · ADU cost
What it costs to build an ADU in Round Lake, NY
An 800 sq ft accessory dwelling unit in Round Lake 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 Round Lake maps 4 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 Round Lake
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 Round Lake 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 |
|---|---|---|---|---|
| RV-1 Residential (the Village's larger-lot residential district: a 14,000 SQ FT minimum lot, 100 ft of frontage width, 40 ft front, 20 ft side and 50 FT REAR yards for a principal structure, 35 ft of height, a 1,000 sq ft minimum available building area — and A MAXIMUM LOT COVERAGE OF ONLY 15%. SINGLE-FAMILY DWELLINGS ONLY — RV-1 does not permit two-family dwellings, unlike RV-2 — and THE VILLAGE'S ARCHITECTURAL STANDARDS MUST BE MET FOR ALL NEW CONSTRUCTION IN THIS ZONE, a design-review layer on top of the dimensional one (and themselves amended by L.L. No. 2-2026, adopted 4-15-2026 and not yet codified, so read the local law). Customary agricultural operations are permitted, but raising poultry or livestock needs a special permit. ACCESSORY ITEMS HAVE THEIR OWN, MUCH TIGHTER ENVELOPE: 40 ft front, 7 ft side, 10 ft rear and A 12 FT HEIGHT CAP. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. Short-term rentals and bed-and-breakfasts require a special use permit from the Zoning Board of Appeals under § 180-27.1 and the Board of Trustees may cap their number in this zone by resolution — see strNotes. No accessory apartment or ADU provision exists anywhere in Ch. 180.) | 0.32 ac | 40 / 20 / 50 ft | 35 ft | No |
| RV-2 Residential (the Village's denser residential district and the ONLY ONE THAT PERMITS TWO-FAMILY DWELLINGS: a 7,000 SQ FT minimum lot — HALF of RV-1's and the smallest in the Village — 70 ft of frontage width, 20 ft front, 10 ft side and 30 ft rear yards, a 30 ft height, a 900 sq ft minimum available building area and a 20% maximum lot coverage. Professional offices — physician, dentist, lawyer, engineer, architect, accountant — are permitted WITHIN A DWELLING OCCUPIED BY THE SAME PERSON, with off-street parking for clients: a live-work allowance tied to occupancy, not a general office use. THE ACCESSORY ENVELOPE IS THE TIGHTEST IN THE VILLAGE: 20 ft front, 3 FT side, 3 FT rear and AN 8 FT HEIGHT CAP — three feet from the line and eight feet tall, which rules out most detached garages as of right. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. Short-term rentals and bed-and-breakfasts require a special use permit from the Zoning Board of Appeals under § 180-27.1 and the Board of Trustees may cap their number in this zone by resolution — see strNotes. No accessory apartment or ADU provision exists anywhere in Ch. 180; the two-family dwelling is the route to a second unit here.) | 0.16 ac | 20 / 10 / 30 ft | 30 ft | No |
| CV-1 Commercial (a 30,000 SQ FT minimum lot — the largest developed-district lot in the Village, more than TWICE RV-1's and over four times RV-2's — with 150 ft of frontage width, 40 ft front, 30 ft side and 30 ft rear yards, a 35 ft height, a 1,200 sq ft minimum available building area and a 15% maximum lot coverage. Accessory items get 40 ft front, 10 ft side, 15 ft rear and a 12 ft height cap. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. No accessory apartment or ADU provision exists anywhere in Ch. 180.) | 0.69 ac | 40 / 30 / 30 ft | 35 ft | No |
| LCV Land Conservation (undeveloped land, with A 10-ACRE MINIMUM LOT FOR A PRINCIPAL STRUCTURE and accessory structures BY SPECIAL PERMIT ONLY. The 10-acre figure is qualified by table note 3, which points at 'large structures as defined in § 180-16B' — so the 10-acre minimum attaches to the large-structure case rather than to every conceivable use, and § 180-16 should be read before applying it. PERMITTED USES ARE NARROW AND ARE NOT HOUSING: customary agricultural operations (with raising poultry or livestock requiring a special permit, and sale of produce grown on the premises permitted), golf and country clubs, and small accessory buildings serving those uses. Underwrite LCV as open space. ) | 10 ac | — | — | No |
Size limits on record in Round Lake
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 Round Lake:
- RV-1 Residential (the Village's larger-lot residential district: a 14,000 SQ FT minimum lot, 100 ft of frontage width, 40 ft front, 20 ft side and 50 FT REAR yards for a principal structure, 35 ft of height, a 1,000 sq ft minimum available building area — and A MAXIMUM LOT COVERAGE OF ONLY 15%. SINGLE-FAMILY DWELLINGS ONLY — RV-1 does not permit two-family dwellings, unlike RV-2 — and THE VILLAGE'S ARCHITECTURAL STANDARDS MUST BE MET FOR ALL NEW CONSTRUCTION IN THIS ZONE, a design-review layer on top of the dimensional one (and themselves amended by L.L. No. 2-2026, adopted 4-15-2026 and not yet codified, so read the local law). Customary agricultural operations are permitted, but raising poultry or livestock needs a special permit. ACCESSORY ITEMS HAVE THEIR OWN, MUCH TIGHTER ENVELOPE: 40 ft front, 7 ft side, 10 ft rear and A 12 FT HEIGHT CAP. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. Short-term rentals and bed-and-breakfasts require a special use permit from the Zoning Board of Appeals under § 180-27.1 and the Board of Trustees may cap their number in this zone by resolution — see strNotes. No accessory apartment or ADU provision exists anywhere in Ch. 180.)So the second unit is as-of-right on a 7,000 sq ft RV-2 lot and unavailable on a 14,000 sq ft RV-1 lot
- RV-2 Residential (the Village's denser residential district and the ONLY ONE THAT PERMITS TWO-FAMILY DWELLINGS: a 7,000 SQ FT minimum lot — HALF of RV-1's and the smallest in the Village — 70 ft of frontage width, 20 ft front, 10 ft side and 30 ft rear yards, a 30 ft height, a 900 sq ft minimum available building area and a 20% maximum lot coverage. Professional offices — physician, dentist, lawyer, engineer, architect, accountant — are permitted WITHIN A DWELLING OCCUPIED BY THE SAME PERSON, with off-street parking for clients: a live-work allowance tied to occupancy, not a general office use. THE ACCESSORY ENVELOPE IS THE TIGHTEST IN THE VILLAGE: 20 ft front, 3 FT side, 3 FT rear and AN 8 FT HEIGHT CAP — three feet from the line and eight feet tall, which rules out most detached garages as of right. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. Short-term rentals and bed-and-breakfasts require a special use permit from the Zoning Board of Appeals under § 180-27.1 and the Board of Trustees may cap their number in this zone by resolution — see strNotes. No accessory apartment or ADU provision exists anywhere in Ch. 180; the two-family dwelling is the route to a second unit here.)So the second unit is as-of-right on a 7,000 sq ft RV-2 lot and unavailable on a 14,000 sq ft RV-1 lot
- CV-1 Commercial (a 30,000 SQ FT minimum lot — the largest developed-district lot in the Village, more than TWICE RV-1's and over four times RV-2's — with 150 ft of frontage width, 40 ft front, 30 ft side and 30 ft rear yards, a 35 ft height, a 1,200 sq ft minimum available building area and a 15% maximum lot coverage. Accessory items get 40 ft front, 10 ft side, 15 ft rear and a 12 ft height cap. THE TABLE CARRIES A 'MINIMUM AVAILABLE BUILDING AREA' COLUMN, WHICH IS A FLOOR RATHER THAN A CEILING AND IS UNUSUAL ENOUGH TO CONFIRM BEFORE RELYING ON: the phrase is not defined in § 180-3, and it reads either as a minimum building size or as a minimum contiguous buildable area remaining on the lot after setbacks. Either way it is a MINIMUM, so it works against small structures rather than large ones. Get the Building Department's reading at (518) 899-2800 before designing to it. No accessory apartment or ADU provision exists anywhere in Ch. 180.)So the second unit is as-of-right on a 7,000 sq ft RV-2 lot and unavailable on a 14,000 sq ft RV-1 lot
- LCV Land Conservation (undeveloped land, with A 10-ACRE MINIMUM LOT FOR A PRINCIPAL STRUCTURE and accessory structures BY SPECIAL PERMIT ONLY. The 10-acre figure is qualified by table note 3, which points at 'large structures as defined in § 180-16B' — so the 10-acre minimum attaches to the large-structure case rather than to every conceivable use, and § 180-16 should be read before applying it. PERMITTED USES ARE NARROW AND ARE NOT HOUSING: customary agricultural operations (with raising poultry or livestock requiring a special permit, and sale of produce grown on the premises permitted), golf and country clubs, and small accessory buildings serving those uses. Underwrite LCV as open space. )So the second unit is as-of-right on a 7,000 sq ft RV-2 lot and unavailable on a 14,000 sq ft RV-1 lot
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 rentalsShort-term rentals allowed with local rules. THE STATED PURPOSE IS EXPLICITLY ANTI-ABSENTEE: the Board of Trustees found that these uses benefit owners and visitors and make for a more diverse residential and recreational landscape, but that 'the operation of a bed-and-breakfast or a short-term rental BY ABSENTEE OWNERS is a business use which may be inappropriate for residential neighborhoods and may lead to less interest by such owners in the good will of their neighbors and the condition of their properties. Business goals and residential goals are different.' Read that before assuming an investor-owned STR is viable here. THERE IS A SATURATION TEST AND A CAPPING POWER, WHICH TOGETHER MAKE THIS A SUPPLY-LIMITED MARKET: the ZBA may refuse a permit where the area would be 'saturated by the proposed use', with the code's own example being THREE RENTAL ROOMS WITHIN THE SURROUNDING 150 FEET; and § 180-27.1D empowers the BOARD OF TRUSTEES TO ESTABLISH, BY RESOLUTION, A CAP ON THE NUMBER OF SHORT-TERM RENTALS FOR SPECIFIC ZONES (the code names RV-1, RV-2 and planned development districts as examples), provided the resolution sets out a factual finding justifying the cap. THE CAP LIVES IN A TRUSTEES' RESOLUTION, NOT IN THE ZONING CHAPTER, SO IT WILL NOT APPEAR ON eCODE360 — call the Village office at (518) 899-2800 and ask whether a cap resolution is in force for the zone in question and how many permits are outstanding. 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) 899-2800
Sizing up a specific parcel in Round Lake?
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 Round Lake runs $204–268/sq ft, about $370k–480k at 1,800 sq ft . See what it costs to build a house in Round Lake.
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) · Schuylerville (Village) · South Glens Falls (Village) · Stillwater (Village) · Victory (Village) · Waterford (Village)
More on Round Lake: Can you build an ADU here? · Zoning for new construction · Saratoga County build cost
ADU cost in Round Lake: common questions
How much does it cost to build an ADU in Round Lake, NY?
An 800 sq ft accessory dwelling unit in Village of Round Lake 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 Round Lake?
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 Round Lake?
Village of Round Lake has 4 districts. All districts prohibit ADUs. Check the specific address with the free ADU checker or confirm with the building department at (518) 899-2800 before you spend money on design.
Can I rent an ADU in Round Lake short term?
Short-term rentals allowed with local rules for Village of Round Lake. 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 Round Lake 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) 899-2800 before relying on any answer. Sources: Offsite / Aldo cost engine (costEngine.js + constants.js); zoning dataset (municipalData.js).