ADU · Ulster County

Can you build an ADU in Gardiner, NY?

Town of Gardiner has 8 districts. 6 districts allow ADUs with occupancy restrictions, 2 do not. Check your address to confirm the district that applies to your parcel:

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What the Gardiner code says

An accessory apartment is allowed in every district except SP-2 and SP-3, but the owner has to live on the property. It is capped at 1,000 sq ft, or 30% of the main building's floor space if it is inside the house. In CLI and HC it also needs site plan review.

Conditions the code attaches:

The property owner has to live in the structure containing the apartment, or on the property if it is in a detached accessory structure (§ 220-74).
One accessory apartment is allowed per single-family dwelling, either inside the principal building or in an accessory structure (§ 220-12C).
Inside the principal building the apartment is capped at the lesser of 1,000 sq ft or 30% of that building's floor space; in a detached accessory structure it is capped at 1,000 sq ft (§ 220-74).
The lot has to meet the minimum acreage for its district unless the apartment is in an approved open space development, which means 5 acres in RA (§ 220-12C).
On a nonconforming lot in any district, the apartment needs a special use permit instead (§ 220-12C and Use Table footnote 9).
The same applies on an RA small-scale development under 5 acres conforming under § 220-24.
Approval or certification from the Ulster County Department of Health that the septic system is adequate has to come first (§ 220-12C).
In CLI and HC the apartment is permitted by right but needs Planning Board site plan review (§ 220-10B).
The apartment is not counted as a dwelling unit for density, and it is excluded from the limit of 8 dwelling units per acre in HM and HR (§ 220-12C, § 220-11E).
An accessory apartment is prohibited in the SP-2 and SP-3 subdistricts of the Shawangunk Ridge Protection District, whose use list in § 220-16I does not include it.

How big an ADU can be in Gardiner

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.

Inside the principal dwelling

30% of the principal dwelling, or 1,000 sq ft of floor area — whichever is smaller

RA, HM, HR, CLI, HC, SP1 · owner-occupancy required · § 220-74, definition of accessory apartment

Detached

1,000 sq ft of floor area

RA, HM, HR, CLI, HC, SP1 · owner-occupancy required · § 220-74, definition of accessory apartment

What the Gardiner 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
RA Rural Agricultural	5 ac	30 / 30 / 50 ft	35 ft	Occupancy restricted
HM Hamlet Mixed-Use	1.84 ac	10 / 10 / 15 ft	45 ft	Occupancy restricted
HR Hamlet Residential	1.84 ac	10 / 15 / 15 ft	40 ft	Occupancy restricted
CLI Commercial/Light Industrial	2 ac	40 / 20 / 50 ft	35 ft	Occupancy restricted
HC Highway Commercial	2 ac	30 / 20 / 50 ft	35 ft	Occupancy restricted
SP-1 Shawangunk Ridge Protection	5 ac	75 / 50 / 100 ft	35 ft	Occupancy restricted
SP-2 Shawangunk Ridge Protection (Middle Slope)	10 ac	75 / 50 / 100 ft	25 ft	No
SP-3 Shawangunk Ridge Protection (Upper Slope)	20 ac	75 / 50 / 100 ft	25 ft	No

RA Rural Agricultural - The coverage figure is maximum impervious surface, not building coverage (§ 220-74). The width shown is the minimum road frontage for a conventional subdivision on a town road; the table publishes no lot width at all.

Minimum road frontage on a county or state road is 300 ft.
The setbacks shown are for conventional development (§ 220-74); in an open space development they are set by § 220-20E and the minimum lot size by § 220-11D.
Maximum base density in an open space development is 2 acres per dwelling unit before bonuses.
The maximum footprint for a nonresidential structure is 6,000 sq ft.
The impervious surface limit applies to each lot and to a whole subdivision including new roads, and does not apply to agricultural uses or pre-existing nonconforming lots.
An applicant may exceed the impervious surface limit using partially permeable materials under § 220-11C.

HM Hamlet Mixed-Use - The minimum lot runs 80,000 sq ft with neither utility, 40,000 with common or municipal water only, 20,000 with sewage disposal only, and 10,000 with both (§ 220-11D).

Density is capped at 8 dwelling units per acre of buildable land however the lot and density rules combine, counting a studio as 0.5 of a unit, a one-bedroom as 0.67 and a two-bedroom as 0.75.
With sewage disposal only, the Planning Board may cut the minimum to 7,500 sq ft in the Town Center hamlet area if well tests paid for by the applicant show no adverse effect on surrounding wells.
The Planning Board may cut the both-utilities minimum for inclusionary housing, over-sized infrastructure, municipal support services or transferred development rights, but never below 6,000 sq ft.
The coverage figure is maximum impervious surface rather than building coverage (§ 220-74), and it applies to a whole subdivision including new roads as well as to each lot.
The front yard is a range of 10 ft to 25 ft on a town or private road and 15 ft to 35 ft on a county or state road, and the side yard may be 0 for a party-wall or zero-lot-line building.
A nonresidential footprint is capped at 10,000 sq ft, rising to 60,000 for a supermarket, cinema or similar destination use that meets the special permit impact criteria.

HR Hamlet Residential - The minimum lot runs 80,000 sq ft with neither utility, 40,000 with common or municipal water only, 20,000 with sewage disposal only, and 10,000 with both (§ 220-11D).

Density is capped at 8 dwelling units per acre of buildable land however the lot and density rules combine, counting a studio as 0.5 of a unit, a one-bedroom as 0.67 and a two-bedroom as 0.75.
With sewage disposal only, the Planning Board may cut the minimum to 7,500 sq ft in the Town Center hamlet area if well tests paid for by the applicant show no adverse effect on surrounding wells.
The Planning Board may cut the both-utilities minimum for inclusionary housing, over-sized infrastructure, municipal support services or transferred development rights, but never below 6,000 sq ft.
The coverage figure is maximum impervious surface rather than building coverage (§ 220-74), and it applies to a whole subdivision including new roads as well as to each lot.
The front yard is a range of 10 ft to 25 ft on a town or private road and 15 ft to 40 ft on a county or state road, and the side yard may be 0 for a party-wall or zero-lot-line building.
The footprint of a nonresidential structure is capped at 1,000 sq ft.

CLI Commercial/Light Industrial - Where the lot abuts a residential district the side and rear setbacks become 100 ft with a wooded buffer, for structures, driveways, parking and any paved area.

On a county or state road the minimum road frontage is 200 ft and the front yard is 125 ft, against 40 ft on a town road.
The coverage figure is maximum impervious surface, not building coverage (§ 220-74).
The width shown is the minimum road frontage for a conventional subdivision on a town road; the table publishes no lot width at all.
The maximum footprint for a nonresidential structure is 200,000 sq ft.
The impervious surface limit applies to each lot and to a whole subdivision including new roads, and does not apply to agricultural uses or pre-existing nonconforming lots.
An applicant may exceed the impervious surface limit using partially permeable materials under § 220-11C.

HC Highway Commercial - Where the lot abuts a residential district the side and rear setbacks become 100 ft with a wooded buffer, for structures, driveways, parking and any paved area.

On a county or state road the minimum road frontage is 300 ft and the front yard is 40 ft, against 30 ft on a town road.
The coverage figure is maximum impervious surface, not building coverage (§ 220-74).
The width shown is the minimum road frontage for a conventional subdivision on a town road; the table publishes no lot width at all.
The maximum footprint for a nonresidential structure is 60,000 sq ft.
The impervious surface limit applies to each lot and to a whole subdivision including new roads, and does not apply to agricultural uses or pre-existing nonconforming lots.
An applicant may exceed the impervious surface limit using partially permeable materials under § 220-11C.

SP-1 Shawangunk Ridge Protection - The coverage figure is maximum impervious surface, not building coverage (§ 220-74). The width shown is the minimum road frontage for a conventional subdivision on a town road; the table publishes no lot width at all.

Minimum road frontage on a county or state road is 300 ft.
Maximum base density in an open space development is 5 acres per dwelling unit before bonuses.
Lot sizes and setbacks in an open space development are set by §§ 220-11D and 220-20E.
The maximum footprint for a nonresidential structure is 6,000 sq ft.
The impervious surface limit applies to each lot and to a whole subdivision including new roads, and does not apply to agricultural uses or pre-existing nonconforming lots.
An applicant may exceed the impervious surface limit using partially permeable materials under § 220-11C.

SP-2 Shawangunk Ridge Protection (Middle Slope), SP-3 Shawangunk Ridge Protection (Upper Slope) - The dimensional regulations for this district are at § 220-16 rather than in the § 220-11 dimensional table.

ADUs vs. short-term rentals in Gardiner

Short-term-rental status not confirmed for Town of Gardiner. The short-term rental rules here are not confirmed. The town was drafting short-term rental regulations as of 2024, so confirm the current requirements before counting on that income. 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 minimum1.84–5 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/GA1939
Building dept(845) 255-9675

ADU FAQ — Gardiner, NY

Are ADUs allowed in Gardiner, NY?

Town of Gardiner has 8 districts. 6 districts allow ADUs with occupancy restrictions, 2 do not. Check your address with the free ADU checker, or confirm with the building department at (845) 255-9675.

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

No district in Town of Gardiner requires a special-use permit for an ADU - 6 districts allow ADUs with occupancy restrictions, 2 do not. Site-plan review or a building permit may still apply.

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

Short-term-rental status not confirmed for Town of Gardiner. 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 Gardiner

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 Gardiner, priced by size.

How we know this

Sections analyzed: § 220-10B (Use Table) · § 220-12B(3) · § 220-12C · § 220-16B(2) · § 220-16I (SP-2 and SP-3 Use Table) · § 220-74 (definition of accessory apartment)
Districts confirmed: 8 of 8 — every mapped district.
Last reviewed: Apr 2026
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 Gardiner: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Ulster County · All Ulster County towns

ADU information for Town of Gardiner 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) 255-9675 before relying on any answer. Source: the Offsite / Aldo zoning dataset.