Red Hook · ADU cost
What it costs to build an ADU in Red Hook, NY
An 800 sq ft accessory dwelling unit in Red Hook runs roughly $210k–275k, or about $263–345/sq ft, and that per-square-foot figure sits deliberately above the $215–282/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 Red Hook maps 13 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 Red Hook
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Dutchess County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $349–$457 | $140k–185k |
| 600 sq ft | One bedroom | $292–$382 | $175k–230k |
| 800 sq ft | One bedroom, larger | $263–$345 | $210k–275k |
| 1,000 sq ft | Two bedroom | $246–$322 | $245k–320k |
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 | $8–$12 | $8 | — |
| Foundation | $17–$24 | $17 | — |
| Framing | $27–$34 | $27 | — |
| Envelope - roof, siding, windows | $34–$43 | $34 | — |
| Plumbing | $29–$36 | $17 | 55% |
| Electrical | $19–$25 | $13 | 35% |
| HVAC | $24–$30 | $15 | 45% |
| Insulation | $8–$10 | $8 | — |
| Interior finishes | $34–$46 | $29 | 15% |
| Millwork & cabinetry | $19–$29 | $12 | 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 Red Hook 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 |
|---|---|---|---|---|
| Waterfront Conservation | 10 ac | 100 / 75 / 75 ft | 35 ft | No |
| Limited Development | 10 ac | 100 / 75 / 75 ft | 35 ft | Special permit |
| Rural Development 5-Acre | 5 ac | 75 / 50 / 50 ft | 35 ft | Special permit |
| Rural Development 3-Acre | 3 ac | 60 / 35 / 35 ft | 35 ft | Special permit |
| Residential 1.5-Acre | 1.5 ac | 50 / 20 / 25 ft | 35 ft | Special permit |
| Residential 1-Acre | 1 ac | 35 / 15 / 25 ft | 35 ft | Special permit |
| Hamlet | 1.5 ac | 50 / 20 / 25 ft | 35 ft | Special permit |
| Institutional | 10 ac | 100 / 50 / 50 ft | 35 ft | Special permit |
| Business 1 | 1 ac | 80 / 20 / 50 ft | 35 ft | Special permit |
| Business 2 | 1.5 ac | 80 / 20 / 50 ft | 35 ft | Special permit |
| Hamlet Business | 1 ac | 40 / 20 / 50 ft | 35 ft | Special permit |
| Agricultural Business District | — | 25 / 100 / 100 ft | 35 ft | Special permit |
| Traditional Neighborhood Development District | — | — | — | As of right |
Waterfront Conservation - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 90% of the lot must remain open space.
- Residential uses carry additional special permit criteria under § 143-53.
- Minimum frontage is 300 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 60 ft at the front and 50 ft at the side and rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Limited Development - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 85% of the lot must remain open space.
- Minimum frontage is 240 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 60 ft at the front and 50 ft at the side and rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Rural Development 5-Acre - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 80% of the lot must remain open space.
- Minimum frontage is 200 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 50 ft at the front and 25 ft at the side and rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Rural Development 3-Acre - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 80% of the lot must remain open space.
- Minimum frontage is 160 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 35 ft at the front and 20 ft at the side and rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Residential 1.5-Acre - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 70% of the lot must remain open space.
- Minimum frontage is 135 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 25 ft at the front, 10 ft at the side and 15 ft at the rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Residential 1-Acre - The lot minimum shown applies to a permitted one- or two-family dwelling; other residential types and nonresidential uses follow Article V or the special-permit standards at § 143-52 et seq. At least 65% of the lot must remain open space.
- The side yard may be cut to zero for zero-lot-line residential development.
- Minimum frontage is 120 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 15 ft at the front, 5 ft at the side and 15 ft at the rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Hamlet - The figures shown are for Upper Red Hook. Annandale and Barrytown are stricter: a lot of at least 5 acres, at least 300 ft of lot width and 200 ft of frontage, a 75 ft front, 50 ft side and 50 ft rear yard, 5% coverage and at least 80% open space.
- In Upper Red Hook, the front yard is 100 ft for parcels with frontage on the west side of Route 9.
- In Annandale and Barrytown, the front yard may drop to 25 ft where that matches the established setback on contiguous parcels on the same street.
- In Upper Red Hook, minimum frontage is 135 ft and at least 70% of the lot must be open space.
- Parking and accessways are set back 25 ft front, 10 ft side and 15 ft rear in Upper Red Hook, and 50, 25 and 25 ft in Annandale and Barrytown, except a driveway for a one- or two-family dwelling.
- The side yard may be cut to zero for zero-lot-line residential development.
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Institutional - A permitted residential dwelling does not use these figures: it follows the LD standards west of NYS Route 9G and the RD3 standards anywhere else in town. Residential uses also carry the additional special permit criteria at § 143-53.
- Minimum frontage is 320 ft, a separate requirement from lot width.
- At least 75% of the lot must be open space.
- Off-street parking and its accessways must be set back 60 ft at the front and 25 ft at the side and rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Business 1 - A permitted residential dwelling here follows the R1 standards instead of this district's own. At least 40% of the lot must be open space.
- Minimum frontage is 120 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 40 ft at the front, 10 ft at the side and 25 ft at the rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Business 2 - A permitted residential dwelling here follows the R1 standards instead of this district's own. At least 35% of the lot must be open space.
- Minimum frontage is 160 ft, a separate requirement from lot width.
- Off-street parking and its accessways must be set back 40 ft at the front, 10 ft at the side and 25 ft at the rear, except a driveway serving a one- or two-family dwelling.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Hamlet Business - A permitted residential dwelling follows the R1 standards instead of these. The side yard doubles where the lot is adjacent to a residential district, and the front yard is 100 ft rather than 40 for parcels with frontage on the west side of Route 9.
- Parking setbacks and the rest of the HB standards are set by § 143-49.3.
- Minimum frontage is 120 ft, a separate requirement from lot width.
- At least 50% of the lot must be open space.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
- Where a side or rear yard abuts land in a more restricted district, that district's requirement applies (§ 143-22).
- Front setbacks increase on parcels fronting a user highway or inside a designated scenic area.
Agricultural Business District - The setbacks shown are for nonresidential uses; a new principal residential building needs only 10 ft from any property boundary, and an accessory structure 3 ft. The 7% coverage cap applies to uses outside a farmstead complex or building envelope.
- The code sets no minimum lot area, lot width or frontage in AB.
- At least 80% of the lot must be open space.
- Off-street parking and accessways are set back 25 ft at the front and 60 ft at the side and rear.
- Unenclosed manure storage must be 100 ft from any lot line, wetland, stream, water body or potable well.
- For a nonresidential use, at least 40% of the open space must sit between the front building line and the right-of-way, or 50% on a corner lot.
Traditional Neighborhood Development District - TND is form-based, with three mapped subdistricts, Commercial Center, Residential Neighborhood and Office-Industrial, each with its own standards in § 143-49.1. In the Residential Neighborhood and Commercial Center the front setback is a build-to range with an 18 ft maximum.
- The Commercial Center caps lot frontage at a maximum as well as a minimum.
- Standards for each subdistrict are in § 143-49.1, subsections I through Q.
Size limits on record in Red Hook
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 Red Hook:
- Waterfront ConservationIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Limited DevelopmentIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Rural Development 5-AcreIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Rural Development 3-AcreIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Residential 1.5-AcreIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Residential 1-AcreIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- HamletIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- InstitutionalIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Business 1In an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Business 2In an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Hamlet BusinessIn an existing house the unit is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller, with at most two bedrooms and one per house.
- Agricultural Business DistrictAn accessory apartment in an existing house is capped at 35% of the existing habitable space or 650 sq ft, whichever is smaller.
- Traditional Neighborhood Development DistrictAn ancillary unit of up to 600 sq ft, inside the house or in a back building such as over a garage, is a permitted use in the Residential Neighborhood area and on side streets in the Commercial Center area. It is not listed in the Office-Industrial area.
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 rentalsShort-term rentals allowed with local rules. Every short-term rental, hosted or un-hosted, needs an annual Short-Term Rental Operating Permit under Town Code Chapter 112. A hosted rental is limited to one bedroom and 210 days a year, and any other short-term rental to 120 days a year. Separate question from whether you can build the unit.
- Zoning codeecode360.com/5088409
- Building dept(845) 758-4600
Sizing up a specific parcel in Red Hook?
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 Red Hook runs $215–282/sq ft, about $390k–510k at 1,800 sq ft , plus roughly $38,658 for a conforming lot. See what it costs to build a house in Red Hook.
ADU cost in nearby towns
All Dutchess County towns: Beacon (City) · Poughkeepsie (City) · Amenia · Beekman · Clinton · Dover · East Fishkill · Fishkill · Hyde Park · La Grange · Milan · North East · Pawling · Pine Plains · Pleasant Valley · Poughkeepsie · Rhinebeck · Stanford · Union Vale · Wappinger · Washington · Fishkill (Village) · Millbrook (Village) · Millerton (Village) · Pawling (Village) · Red Hook (Village) · Rhinebeck (Village) · Tivoli (Village) · Wappingers Falls (Village)
More on Red Hook: Can you build an ADU here? · Zoning for new construction · Dutchess County build cost
ADU cost in Red Hook: common questions
How much does it cost to build an ADU in Red Hook, NY?
An 800 sq ft accessory dwelling unit in Town of Red Hook runs roughly $210k–275k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $140k–185k. 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 Red Hook?
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 $263–345/sq ft against $215–282/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Red Hook?
Town of Red Hook has 13 districts. 11 districts allow ADUs with a special-use permit, 1 allows them, 1 does not. Check the specific address with the free ADU checker or confirm with the building department at (845) 758-4600 before you spend money on design.
Can I rent an ADU in Red Hook short term?
Short-term rentals allowed with local rules for Town of Red Hook. 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 Dutchess 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 Red Hook vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-08-16; verify with the building department at (845) 758-4600 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.