Clermont · ADU cost
What it costs to build an ADU in Clermont, NY
An 800 sq ft accessory dwelling unit in Clermont runs roughly $195k–260k, or about $247–323/sq ft, and that per-square-foot figure sits deliberately above the $202–265/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 Clermont maps 6 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 Clermont
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Columbia County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $327–$428 | $130k–170k |
| 600 sq ft | One bedroom | $273–$358 | $165k–215k |
| 800 sq ft | One bedroom, larger | $247–$323 | $195k–260k |
| 1,000 sq ft | Two bedroom | $231–$302 | $230k–300k |
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 | $27–$33 | $16 | 55% |
| Electrical | $18–$23 | $13 | 35% |
| HVAC | $23–$28 | $14 | 45% |
| Insulation | $7–$9 | $7 | — |
| Interior finishes | $32–$43 | $27 | 15% |
| Millwork & cabinetry | $18–$27 | $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 Clermont 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 |
|---|---|---|---|---|
| Residential Agricultural | 2 ac | 50 / 30 / 50 ft | 35 ft | Special permit |
| Hamlet | 1 ac | 25 / 25 / 25 ft | 35 ft | Special permit |
| Residential Limited Business (3A) | 3 ac | 75 / 50 / 75 ft | 35 ft | Special permit |
| Low Density Residential | 5 ac | 75 / 50 / 100 ft | 35 ft | Special permit |
| Residential Limited Business (1A) | 1 ac | 50 / 20 / 30 ft | 35 ft | Special permit |
| Roe Jan Corridor | 5 ac | 50 / 50 / 50 ft | 35 ft | Special permit |
Residential Agricultural - A multifamily dwelling needs no more land than a single-family one here, so the 2 acre minimum applies either way (§ 4.14.17). Every lot also needs at least 50 ft of road frontage.
- A manufactured home park is permitted in RA only, on at least 10 acres able to hold 20 homes, with each home lot at least 10,000 sq ft and nothing within 50 ft of the street or any property line.
- At least 10% of the park must be open space or recreation, and the perimeter carries two staggered rows of evergreens at least 6 ft high and no more than 16 ft apart.
- Existing one-acre RA parcels in common ownership are preserved as one-acre lots (§ 3.22), and converting a one-family residence to two-family or multifamily keeps the existing lot area.
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line.
- Wind energy conversion systems may reach 150 ft, and the 35 ft limit does not bind silos, barns, church spires, solar equipment or telecommunication towers; the ZBA may approve above it (§ 4.5).
- The 700 sq ft floor minimum excludes the basement and does not apply to apartment units, and no single commercial building may exceed 20,000 sq ft of lot coverage (§ 4.6).
Hamlet - Every lot needs at least 50 ft of road frontage. A multifamily dwelling needs the same minimum lot area as a single-family dwelling in this district, so no extra land is required for it (§ 4.14.17).
- Converting an existing one-family residence to a two-family or multifamily one can keep the existing lot area by special permit (§ 4.14.10). That route does not reach new construction.
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line.
- No single commercial building may exceed 20,000 sq ft of lot coverage (§ 4.6).
- The 700 sq ft floor space minimum applies per single-family dwelling unit, excluding the basement, and not to apartment units; an accessory apartment must be smaller than the unit it serves (§ 4.6).
- The 35 ft height limit does not bind telecommunication towers, church spires, silos, barns or other farm structures or flagpoles, and the Zoning Board of Appeals may approve above it (§ 4.5).
- Wind energy conversion systems may reach 150 ft rather than the 35 ft building limit. Setbacks are measured from property lines.
Residential Limited Business (3A) - Every lot needs at least 50 ft of road frontage, on top of the figures shown. A multifamily dwelling needs no more land than a single-family one in this district (§ 4.14.17).
- No single commercial building may exceed 20,000 sq ft of lot coverage (§ 4.6).
- Converting an existing one-family residence to a two-family or multifamily one keeps the existing lot area, by special permit (§ 4.14.10). It does not reach new construction.
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line. Setbacks are measured from property lines.
- The 35 ft height limit does not bind church spires, telecommunication towers, silos, barns, solar equipment or flagpoles (§ 4.5), and the Zoning Board of Appeals may approve above it.
- Wind energy conversion systems may reach 150 ft rather than the 35 ft building limit.
- The 700 sq ft minimum floor space is per single-family dwelling unit, excluding the basement. It does not apply to apartment units (§ 4.6).
Low Density Residential - A multifamily dwelling needs no more land than a single-family house in the same district (§ 4.14.17). Every district also requires 50 ft of minimum road frontage, which the table does not show.
- Converting an existing one-family residence to a two-family or multifamily one keeps the existing lot area, by special permit (§ 4.14.10). It does not reach new construction.
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line.
- The 700 sq ft of floor space is required per single-family dwelling unit and excludes the basement; it does not apply to apartment units (§ 4.6).
- An accessory apartment must be smaller than the unit it is accessory to.
- The 35 ft height limit does not bind silos, barns or other farm structures, church spires, solar equipment or flagpoles (§ 4.5), and the Zoning Board of Appeals may approve above it.
- Wind energy conversion systems may reach 150 ft rather than the 35 ft building limit.
Residential Limited Business (1A) - Every lot needs at least 50 ft of road frontage, on top of the figures shown. A multifamily dwelling needs no more land than a single-family one: the minimum lot area is the same in this district (§ 4.14.17).
- No single commercial building may exceed 20,000 sq ft of lot coverage (§ 4.6).
- Converting an existing one-family residence to a two-family or multifamily one keeps the existing lot area, by special permit; it does not reach new construction (§ 4.14.10).
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line.
- The 700 sq ft minimum applies per single-family dwelling unit and excludes the basement. It does not apply to apartment units (§ 4.6).
- The 35 ft height limit does not bind church spires, silos, barns and other farm structures, solar equipment or flagpoles, and the Zoning Board of Appeals may approve above it (§ 4.5).
- Setbacks are measured from property lines.
Roe Jan Corridor - A lot here must also have 450 ft of stream frontage (schedule note 1), in addition to the lot width shown. Minimum road frontage is 50 ft.
- No single commercial building may exceed 20,000 sq ft of lot coverage (§ 4.6).
- The 700 sq ft floor area applies per single-family dwelling unit and excludes the basement; it does not apply to apartment units (§ 4.6).
- An accessory structure may not stand in a front yard, nor within 10 ft of any side or rear property line (schedule note 3).
- The minimum lot area for a multifamily dwelling is the same as for a single-family dwelling in this district (§ 4.14.17).
- Converting an existing one-family residence to a two-family or multifamily one keeps the existing lot area by special permit (§ 4.14.10); it does not reach new construction.
- Wind energy conversion systems may reach 150 ft, and the 35 ft limit does not bind telecommunication towers, church spires, silos, barns or other farm structures, solar equipment or flagpoles (§ 4.5).
Size limits on record in Clermont
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 Clermont:
- Residential AgriculturalSize: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
- HamletSize: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
- Residential Limited Business (3A)Size: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
- Low Density ResidentialSize: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
- Residential Limited Business (1A)Size: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
- Roe Jan CorridorSize: at least 500 sf of net floor area, no more than 75% of the primary dwelling's square footage, and in no event more than 1,500 sf (§ 4.14.20).
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 Central Hudson 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 local short term rental rules are confirmed for Clermont. Treat that as an open question rather than permission, and confirm with the building department before counting on renting a home short term. Separate question from whether you can build the unit.
- Zoning codeclermontny.gov/wp-content/uploads/2018/11/Clermont-Zoning-Book.pdf
- Building dept(518) 537-6868
Sizing up a specific parcel in Clermont?
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Building a full house instead?
A standard-finish house in Clermont runs $202–265/sq ft, about $365k–475k at 1,800 sq ft , plus roughly $21,228 for a conforming lot. See what it costs to build a house in Clermont.
ADU cost in nearby towns
All Columbia County towns: Hudson (City) · Ancram · Austerlitz · Canaan · Chatham · Claverack · Copake · Gallatin · Germantown · Ghent · Hillsdale · Kinderhook · Livingston · New Lebanon · Stockport · Stuyvesant · Taghkanic · Chatham (Village) · Kinderhook (Village) · Philmont (Village) · Valatie (Village)
More on Clermont: Can you build an ADU here? · Zoning for new construction · Columbia County build cost
ADU cost in Clermont: common questions
How much does it cost to build an ADU in Clermont, NY?
An 800 sq ft accessory dwelling unit in Town of Clermont runs roughly $195k–260k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $130k–170k. 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 Clermont?
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 $247–323/sq ft against $202–265/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Clermont?
Town of Clermont has 6 districts. All districts allow ADUs with a special-use permit. Check the specific address with the free ADU checker or confirm with the building department at (518) 537-6868 before you spend money on design.
Can I rent an ADU in Clermont short term?
No local short-term-rental law on record - which is not the same as permission for Town of Clermont. 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 Columbia 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 Clermont vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-08-16; verify with the building department at (518) 537-6868 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.