ADU · Orange County

Can you build an ADU in Montgomery, NY?

Village of Montgomery has 11 districts. All districts prohibit ADUs. Check your address to confirm the district that applies to your parcel:

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What the Montgomery code says

An accessory dwelling unit is not permitted in any district of the Village of Montgomery. In R-6 and RM-1 an existing single-family detached house can be converted for two families by special exception, which creates two full dwellings.

Conditions the code attaches:

The two-family conversion is prohibited in the five one-family districts.
R-6 and RM-1 also permit a new two-family detached or one-family semidetached dwelling by right, and RM-1 multiple dwellings.
Any use the district's use table does not specifically permit is prohibited there (§ 122-4A).

What the Montgomery 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
Residential One-Family	0.41 ac	40 / 25 / 35 ft	35 ft	No
Residential Agriculture One-Family	0.28 ac	35 / 15 / 35 ft	35 ft	No
Residential One-Family	0.18 ac	30 / 10 / 30 ft	35 ft	No
Residential One-Family	0.23 ac	30 / 10 / 20 ft	35 ft	No
Residential One-Family	0.11 ac	25 / 10 / 25 ft	35 ft	No
Residential One- and Two-Family	0.11 ac	25 / 10 / 25 ft	35 ft	No
Multifamily Residential	0.11 ac	25 / 10 / 25 ft	35 ft	No
Neighborhood Business	0.23 ac	50 / 20 / 30 ft	35 ft	No
Village Business	—	0 / 12 / 20 ft	35 ft	No
Industrial Park	0.92 ac	50 / 30 / 50 ft	35 ft	No
Village Industry	0.11 ac	0 / 12 / 20 ft	35 ft	No

Residential One-Family - The lot size shown is for land with both public sewer and public water. With only one of them a lot needs at least twenty thousand square feet, and with neither, building here is not permitted.

The pair of side yards must total at least forty feet, so a house needs at least twenty-five feet on one side and at least fifteen on the other.
A side yard on the street side of a corner lot must be at least thirty-five feet.
Lot width is measured at the required minimum front yard depth, not at the street.
Coverage counts main and accessory buildings together.
An accessory building may cover up to 20% of the required rear yard, rise no more than 18 feet there, and must stand at least 5 feet from any lot line.
Only a single-family detached dwelling is permitted; a two-family house, a multiple dwelling and a planned residential development are not.

Residential Agriculture One-Family - The lot size shown is for land with both public sewer and public water. With only one of them a lot needs at least eighteen thousand square feet, and with neither at least twenty thousand; RA-3 is the only district in the Village buildable without any public service.

A side yard on the street side of a corner lot must be at least thirty-five feet, the full front-yard figure.
A planned residential development, and a golf course or country club on at least fifty acres, are available by special exception.
Lot width is measured at the required minimum front yard depth.
Coverage counts main and accessory buildings together.
An accessory building may cover up to 20% of the required rear yard, rise no more than 18 feet there, and must stand at least 5 feet from any lot line.

Residential One-Family - At least one public service is required: the lot size shown holds with public sewer and public water or with only one of them, but with neither, building here is not permitted.

Because the pair of side yards must total at least twenty-five feet, one side yard must be at least fifteen feet.
A side yard on the street side of a corner lot must be at least thirty feet.
Lot width is measured at the required minimum front yard depth.
Coverage counts main and accessory buildings together.
A planned residential development is available by special exception.
An accessory building may cover up to 25% of the required rear yard, rise no more than 18 feet there, and must stand at least 3 feet from any lot line.

A side yard on the street side of a corner lot must be at least thirty feet.
Lot width is measured at the required minimum front yard depth.
Coverage counts main and accessory buildings together.
A planned residential development is available by special exception.
An accessory building may cover up to 25% of the required rear yard, rise no more than 18 feet there, and must stand at least 3 feet from any lot line.

The pair of side yards must total at least eighteen feet, with at least ten feet on one side and at least eight on the other.
A side yard on the street side of a corner lot must be at least twenty-five feet.
Only a single-family detached dwelling is permitted.
Lot width is measured at the required minimum front yard depth.
Coverage counts main and accessory buildings together.
An accessory building may cover up to 25% of the required rear yard, rise no more than 18 feet there, and must stand at least 3 feet from any lot line.

Residential One- and Two-Family - Nothing may be built here without both public sewer and public water. Each dwelling unit needs at least twenty-five hundred square feet of land, so the minimum lot carries a two-family house exactly and the per-unit figure is what binds.

A two-family detached dwelling and a one-family semidetached dwelling are permitted by right; converting an existing single-family detached house for two families needs a special exception.
A side yard on the street side of a corner lot must be at least twenty-five feet.
Lot width is measured at the required minimum front yard depth.
Coverage counts main and accessory buildings together.
An accessory building may cover up to 35% of the required rear yard, rise no more than 20 feet there, and must stand at least 3 feet from any lot line.

Multifamily Residential - Land per unit rises with bedroom count: at least five thousand square feet for an efficiency, one- or two-bedroom unit, at least five thousand five hundred for three bedrooms, and at least eight thousand seven hundred for four or more. That ladder sizes a building here.

Nothing may be built here without both public sewer and public water.
The pair of side yards must total at least fifteen feet, with at least ten feet on one side and at least five on the other.
A side yard on the street side of a corner lot must be at least twenty-five feet.
RM-1 is the only district in the Village where a multiple dwelling is permitted.
Coverage counts main and accessory buildings together.
An accessory building may cover up to 35% of the required rear yard, rise no more than 20 feet there, and must stand at least 3 feet from any lot line.

Neighborhood Business - No dwelling of any kind is permitted in B-1. A side yard on the street side of a corner lot must be at least fifty feet, the full front-yard figure.

Lot width is measured at the building line.
Coverage counts main and accessory buildings together.
No separate rear-yard coverage or height limit applies to accessory buildings.

Village Business - No side yard is required, but one that is provided must be at least twelve feet. The rear yard is the only yard that always binds.

The district requires no lot area, no lot width and no front yard, which lets buildings stand on the street line.
No combined side yard and no corner-lot side yard apply.
A dwelling is possible only above a first-floor nonresidential use, and only by special exception.
Coverage counts main and accessory buildings together.
No separate rear-yard coverage or height limit applies to accessory buildings.

Industrial Park - No dwelling of any kind is permitted in I-1. A side yard on the street side of a corner lot must be at least fifty feet.

Lot width is measured at the building line.
Coverage counts main and accessory buildings together.
No separate rear-yard coverage or height limit applies to accessory buildings.

Village Industry - No front yard and no corner-lot side yard are required. The pair of side yards must total at least twenty feet, with at least twelve feet on one side and at least eight on the other.

No dwelling of any kind is permitted.
Lot width is measured at the building line.
Coverage counts main and accessory buildings together.
No separate rear-yard coverage or height limit applies to accessory buildings.

ADUs vs. short-term rentals in Montgomery

Short-term rentals allowed with local rules for Village of Montgomery. Short-term rentals in the Village of Montgomery need a short-term rental permit under the Village's Short-Term Rental Properties chapter, with an annual inspection. 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 minimum0.11–0.41 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/13326521
Building dept(845) 457-9621

ADU FAQ — Montgomery, NY

Are ADUs allowed in Montgomery, NY?

Village of Montgomery has 11 districts. All districts prohibit ADUs. Check your address with the free ADU checker, or confirm with the building department at (845) 457-9621.

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

No. No district in Village of Montgomery permits an ADU, so there is no permit to apply for. Codes change, so verify with the building department at (845) 457-9621 before ruling it out.

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

Short-term rentals allowed with local rules for Village of Montgomery. 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 Montgomery

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $205k–270k 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 Montgomery, priced by size.

How we know this

Sections analyzed: 122 Attachment 3 Residence and Agriculture Use Table (conversion row); 122 Attachment 5 Business and Industrial Use Table; § 122-4
Districts confirmed: 11 of 11 — every mapped district.
Last reviewed: 2026-09-15
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 Montgomery: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Orange County · All Orange County towns

ADU information for Village of Montgomery is compiled from the municipal code (last reviewed 2026-09-15) 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) 457-9621 before relying on any answer. Source: the Offsite / Aldo zoning dataset.