ADU · Ulster County
Can you build an ADU in Marlborough, NY?
Town of Marlborough has 7 districts. All districts prohibit ADUs. Check your address to confirm the district that applies to your parcel:
What the Marlborough 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 |
|---|---|---|---|---|
| R Residential | 0.4591 ac | 10 / 10 / 20 ft | 35 ft | No |
| R-1 Residential | 1 ac | 35 / 35 / 50 ft | 35 ft | No |
| R-Ag-1 Rural Agricultural | 1 ac | 50 / 35 / 75 ft | 35 ft | No |
| C-1 Hamlet Commercial | 0.3444 ac | 5 / 0 / 20 ft | 35 ft | No |
| C-2 Highway Commercial | 0.4591 ac | 35 / 35 / 30 ft | 35 ft | No |
| HD Harbor Development | 2 ac | 75 / 25 / 75 ft | 45 ft | No |
| I Industrial | 5 ac | 75 / 25 / 75 ft | 35 ft | No |
R Residential — A FOURTH ROW EXISTS AND IS NOT RECORDABLE: with public water, public sewer AND natural gas the R minimum drops again to 7,500 sq ft. Natural gas service has no term in the condition vocabulary — water and sewer are the only utility axes — so inventing one would make the figure match nothing. It is stated here instead. Combined side yards 25 ft.
R-1 Residential — Minimum lot size is subject to the percolation tests required by § 155-42, but in no event less than one acre (schedule note 1). Combined side yards 70 ft. Where the lot adjoins active agricultural land, § 155-52 imposes a 75 ft setback from the property line that SUPERSEDES the figures above (schedule note 3). Applies in R-Ag-1, R-1 and HD.
R-Ag-1 Rural Agricultural — Minimum lot size is subject to the percolation tests required by § 155-42, but in no event less than one acre (schedule note 1). Combined side yards 80 ft — more than twice the 35 ft single yard. Where the lot adjoins active agricultural land, § 155-52 imposes a 75 ft setback from the property line that SUPERSEDES the figures above (schedule note 3). Applies in R-Ag-1, R-1 and HD.
C-1 Hamlet Commercial — No side yard is required in C-1, and none is required when provided. Combined side yards 0 ft.
C-2 Highway Commercial — C-2 publishes a figure only in the "Without public water or sewer" row — 20,000 sq ft — and no reduced figure for either utility case. Combined side yards 70 ft.
HD Harbor Development — Four stories and 45 ft, but where the two measures disagree the LESSER applies (schedule note 2). A building over 35 ft requires a SEQRA visual impact analysis because HD lies within the Coastal Boundary Zone. Combined side yards 50 ft. Where the lot adjoins active agricultural land, § 155-52 imposes a 75 ft setback from the property line that SUPERSEDES the figures above (schedule note 3). Applies in R-Ag-1, R-1 and HD.
I Industrial — Combined side yards 50 ft.
ADUs vs. short-term rentals in Marlborough
Short-term rentals allowed with registration for Town of Marlborough. STR permit required in the Town of Marlborough. Contact Building Dept at (845) 236-7600 to confirm current permit requirements, fees, and any operating restrictions. 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. Municipal source
Good to know
- Residential lot minimum0.4591–1 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityCentral Hudson territory.
- Zoning codeecode360.com/MA0587
- Building dept(845) 236-7600
- Last reviewedApr 2026
ADU FAQ — Marlborough, NY
Are ADUs allowed in Marlborough, NY?
Town of Marlborough has 7 districts. All districts prohibit ADUs. Check your address with the free ADU checker, or confirm with the building department at (845) 236-7600.
Do I need a special permit for an ADU in Marlborough?
No. No district in Town of Marlborough permits an ADU, so there is no permit to apply for. Codes change, so verify with the building department at (845) 236-7600 before ruling it out.
Can I use an ADU as a short-term rental in Marlborough?
Short-term rentals allowed with registration for Town of Marlborough. 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.
What an ADU costs to build in Marlborough
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $200k–265k 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 Marlborough, priced by size.
More on Marlborough: Full zoning for new construction · ADU build cost · House build cost · All Ulster County towns
ADU information for Town of Marlborough is compiled from the municipal code (last reviewed Apr 2026) 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) 236-7600 before relying on any answer. Source: Offsite / Aldo zoning dataset, municipalData.js.