ADU · Dutchess County

Can you build an ADU in Fishkill, NY?

Town of Fishkill has 16 districts. 12 districts allow ADUs with occupancy restrictions, 4 do not. Check your address to confirm the district that applies to your parcel:

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What the Fishkill code says

In R-4A, R-2A, R-40, R-20, R-15, R-MF-3, R-MF-5, LHC and RB an accessory apartment needs only a building permit and certificate of occupancy, and the owner must live in the house or the apartment. It is not possible in PSC, which allows no house.

Conditions the code attaches:

The apartment must be less than 50% of the main house's living space, at least 350 sq ft and no more than 1,000 sq ft.
One apartment per property, attached to, inside, or detached from the single-family house on the same lot.
One parking space is required, which may be waived where street parking is adequate.
The certificate of occupancy records the owner-occupancy condition, and a new owner must renew the approval.
The apartment may be let to a tenant: there is no family-only rule and no age limit.
In BH accessory apartments are listed for nonseasonal uses, and those uses also need a § 150-59 land development permit.

How big an ADU can be in Fishkill

Size limits are set per district, and a unit inside the house is a different standard from a detached one. These are the figures the code publishes.

Accessory dwelling unit

At least 350 sq ft, and no more than 50% of the principal dwelling, or 1,000 sq ft of floor area — whichever is smaller

R-4A, R-2A, R-40, R-20, R-15, R-MF-3, R-MF-5, BH, LHC, RB, PI · owner-occupancy required · § 150-40D(1)(a), (d)

1 other district allows an accessory unit but the code publishes no size for it here, so this page does not state one.

What the Fishkill code indicates by district

The table below shows how each district treats ADUs, alongside the lot and setback standards that govern a second unit. District boundaries and conditions vary, so treat this as a starting point and confirm the district that applies to your parcel.

District	Min lot	Setbacks F / S / R	Max height	ADU
One-Family Residence 4-Acre	4 ac	75 / 50 / 60 ft	35 ft	Occupancy restricted
One-Family Residence 2-Acre	2 ac	50 / 40 / 50 ft	35 ft	Occupancy restricted
One-Family Residence 40,000 Square Feet	0.92 ac	50 / 25 / 50 ft	35 ft	Occupancy restricted
One-Family Residence 20,000 Square Feet	0.46 ac	35 / 20 / 40 ft	35 ft	Occupancy restricted
One-Family Residence 15,000 Square Feet	0.34 ac	35 / 15 / 30 ft	35 ft	Occupancy restricted
Multifamily Residence 3	15 ac	50 / 50 / 50 ft	35 ft	Occupancy restricted
Multifamily Residence 5	10 ac	50 / 25 / 50 ft	35 ft	Occupancy restricted
Beacon Hills	0.46 ac	35 / 20 / 40 ft	35 ft	Occupancy restricted
Local Historic Center	0.23 ac	15 / 12 / 25 ft	35 ft	Occupancy restricted
Restricted Business	5 ac	100 / 100 / 100 ft	35 ft	Occupancy restricted
Planned Business	10 ac	100 / 100 / 100 ft	35 ft	No
Planned Shopping Center	75 ac	100 / 100 / 100 ft	45 ft	No
General Business	0.34 ac	25 / 0 / 30 ft	35 ft	Occupancy restricted
Planned Industry	1 ac	50 / 30 / 30 ft	45 ft	Occupancy restricted
Hudson River Waterfront Recreation	—	—	—	No
Hudson River	—	—	—	No

One-Family Residence 4-Acre - The 5% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 100 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

One-Family Residence 2-Acre - The 10% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 75 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

One-Family Residence 40,000 Square Feet - The 12% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 75 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

One-Family Residence 20,000 Square Feet - The 20% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 60 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

One-Family Residence 15,000 Square Feet - The 22% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 60 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 5 ft from any rear or side lot line.

Multifamily Residence 3 - The 20% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 75 ft from the street's center line, the figure that governs on a narrow right-of-way.

These yards apply to the perimeter of the overall lot; setbacks inside it for two-family and multifamily dwellings are set by § 150-73.
Where the rear of a structure faces a side lot line, a rear yard must be provided between them.
Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

Multifamily Residence 5 - The 30% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 75 ft from the street's center line, the figure that governs on a narrow right-of-way.

These yards apply to the perimeter of the overall lot; setbacks inside it for two-family and multifamily dwellings are set by § 150-73.
Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

Beacon Hills - These figures are for nonseasonal uses. A seasonal use has its own row: minimum lot 15,000 sq ft, width 85 ft, depth 100 ft, side yard 15 ft, rear yard 30 ft and coverage 10%.

The 20% coverage cap is on building and paved area together, so driveways and parking count against it.
The front yard must also be at least 60 ft from the street's center line, the figure that governs on a narrow right-of-way.
Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.
An accessory building not over 15 ft high may stand 10 ft from any rear or side lot line.

Local Historic Center - The 50% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 40 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.

Restricted Business - The 60% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 125 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.

Planned Business - The 75% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 125 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.

Planned Shopping Center - The 70% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 125 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 3 stories as well as 45 ft.

General Business - The 75% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 50 ft from the street's center line, the figure that governs on a narrow right-of-way.

No side yard is required.
Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 2 1/2 stories as well as 35 ft.

Planned Industry - The 70% coverage cap is on building and paved area together, so driveways and parking count against it. The front yard must also be at least 75 ft from the street's center line, the figure that governs on a narrow right-of-way.

Whichever front yard figure governs rises by 10 ft along a state or county road.
Height is capped at 3 stories as well as 45 ft.

Hudson River Waterfront Recreation - Confirm the dimensional standards that apply in HRWRD with the Town before relying on this district.

Hudson River - Confirm the dimensional standards that apply in HRD with the Town before relying on this district.

ADUs vs. short-term rentals in Fishkill

No local short-term-rental law on record - which is not the same as permission for Town of Fishkill. The Town of Fishkill has no local short-term rental law as of Jun 2026. That is not the same as permission, so confirm with the Town of Fishkill Building Department before counting on the use. These are separate questions from whether you can build an ADU — a unit you're allowed to add isn't automatically one you're allowed to rent nightly, so check both.

Good to know

Residential lot minimum0.34–15 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/10587983
Building dept(845) 831-7800

ADU FAQ — Fishkill, NY

Are ADUs allowed in Fishkill, NY?

Town of Fishkill has 16 districts. 12 districts allow ADUs with occupancy restrictions, 4 do not. Check your address with the free ADU checker, or confirm with the building department at (845) 831-7800.

Do I need a special permit for an ADU in Fishkill?

No district in Town of Fishkill requires a special-use permit for an ADU - 12 districts allow ADUs with occupancy restrictions, 4 do not. Site-plan review or a building permit may still apply.

Can I use an ADU as a short-term rental in Fishkill?

No local short-term-rental law on record - which is not the same as permission for Town of Fishkill. ADU occupancy and short-term-rental rules are separate: an ADU you can build isn't automatically one you can rent nightly. Confirm both before you count on STR income.

Run the free ADU check for your parcel →

What an ADU costs to build in Fishkill

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $210k–275k at a standard finish, and the per-square-foot rate comes in above a full house because the kitchen, bath, panel and heating plant cost the same either way. See the full cost to build an ADU in Fishkill, priced by size.

How we know this

Sections analyzed: § 150-40D Accessory apartments; 150 Attachment 1 Schedule of Regulations for Residential Districts; 150 Attachment 2 Schedule of Regulations for Nonresidential Districts; § 150-19
Districts confirmed: 16 of 16 — every mapped district.
Last reviewed: 2026-08-16
Not covered here: Overlay districts, the zoning map, and any conditions attached to an individual parcel. Size limits and owner-occupancy terms sit in the code section above, not in this summary.

More on Fishkill: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Dutchess County · All Dutchess County towns

ADU information for Town of Fishkill is compiled from the municipal code (last reviewed 2026-08-16) and provided for decision-support only — not legal or architectural advice. ADU eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; verify with the building department at (845) 831-7800 before relying on any answer. Source: the Offsite / Aldo zoning dataset.