ADU · Ulster County
Can you build an ADU in Plattekill, NY?
Town of Plattekill has 8 districts. 5 districts allow ADUs with occupancy restrictions, 3 do not. Check your address to confirm the district that applies to your parcel:
What the Plattekill code says
One accessory apartment may accompany a single-family detached house in RS1, HR1, RR1.5, AG1.5 and M3, only while the owner lives in the house. It is not allowed in BD40, BD60 or GB80. Added to an existing house it is a Code Enforcement Officer permit; built first, a special use.
Conditions the code attaches:
- Owner occupancy is inspected within 60 days of the permit and again upon transfer of title, and the permit can be revoked and the apartment ordered vacated if the house is not owner-occupied.
- The lot needs at least 10,000 sq ft per dwelling unit, 20,000 sq ft in total. Ask the Code Enforcement Officer whether § 110-12A instead requires twice the district minimum lot area.
- Floor area may not exceed 25% of the floor area of the finished principal structure or 500 sq ft, whichever is greater, with not more than one bedroom and a side or rear entrance only.
- The individual waste disposal system must be certified as adequate for the additional unit by the Department of Health.
- Two off-street parking spaces are required per dwelling unit (§ 110-16A).
- A detached accessory apartment is not expressly authorized; the rule is written around a unit created in conjunction with the house. Confirm siting with the Code Enforcement Officer, (845) 883-7184.
How big an ADU can be in Plattekill
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.
25% of the principal dwelling, or 500 sq ft of floor area — whichever is larger
What the Plattekill 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 |
|---|---|---|---|---|
| RS-1 Residential Settlement | 1 ac | 50 / 30 / 30 ft | 35 ft | Occupancy restricted |
| HR-1 Hamlet Residential | 1 ac | 35 / 30 / 30 ft | 35 ft | Occupancy restricted |
| RR-1.5 Rural Residential | 1.5 ac | 50 / 50 / 50 ft | 35 ft | Occupancy restricted |
| AG-1.5 Agricultural | 1.5 ac | 50 / 50 / 50 ft | 35 ft | Occupancy restricted |
| BD-40 Business District | 0.92 ac | 35 / 25 / 25 ft | 35 ft | No |
| BD-60 Light Business District | 1.38 ac | 35 / 25 / 25 ft | 35 ft | No |
| GB-80 General Business District | 1.84 ac | 50 / 50 / 50 ft | 35 ft | No |
| M-3 Mountain District | 3 ac | 50 / 50 / 50 ft | 35 ft | Occupancy restricted |
RS-1 Residential Settlement - The minimum lot drops to 0.75 acre with central sewage and 0.5 acre with central sewage and water. Any central service cuts the front setback to 40 ft and the side and rear to 25 ft, and the minimum width to 125 ft, or 100 ft with both.
- With central sewage and water the building coverage cap rises to 35%.
- Minimum lot depth falls to 175 ft with central water alone and 150 ft with central sewage.
- The minimum lot area is also the land required for each dwelling unit.
HR-1 Hamlet Residential - The minimum lot drops to 0.75 acre with central sewage and 0.25 acre with central sewage and water, where the minimum width falls to 75 ft and the side and rear yards to 20 ft. Any central service cuts the front setback to 25 ft.
- With central sewage and water the building coverage cap rises to 35% and the minimum depth falls to 100 ft.
- With central water alone or central sewage alone the minimum width is 125 ft and the side and rear yards 25 ft, with a depth of 175 ft on water and 150 ft on sewage.
- The minimum lot area is also the land required for each dwelling unit.
RR-1.5 Rural Residential - The minimum lot drops to 1 acre with central sewage and 0.75 acre with central sewage and water. Either way the front, side and rear setbacks fall to 40 ft, the coverage cap rises to 25%, and the minimum width and depth drop to 150 ft, or 125 ft with both.
- The minimum lot area is also the land required for each dwelling unit.
AG-1.5 Agricultural - The lot area shown is also the land required per dwelling unit. These figures are the column for a lot on its own sewage and water, and the schedule prints the same standards in all four of its utility columns.
BD-40 Business District - The minimum lot drops to 30,000 sq ft with central sewage and 20,000 sq ft with central sewage and water, and either of those lifts the coverage cap to 50%. Where the lot abuts a residential district boundary, add 25 ft to the side and rear yards.
- Any central service cuts the front setback to 25 ft and the minimum width to 125 ft, or 100 ft with central sewage and water.
- The side and rear yards fall to 20 ft with central sewage and water; the minimum depth is 175 ft with central water alone and 150 ft with central sewage.
- The minimum lot area is also the land required for each dwelling unit.
BD-60 Light Business District - The minimum lot drops to 40,000 sq ft with central sewage and 30,000 sq ft with central sewage and water, and either of those lifts the coverage cap to 40%. Where the lot abuts a residential district boundary, add 25 ft to the side and rear yards.
- Any central service cuts the front setback to 25 ft; the minimum width and depth fall to 175 ft with central water alone and 150 ft with central sewage.
- With central sewage and water the side and rear yards fall to 20 ft.
- The minimum lot area is also the land required for each dwelling unit.
GB-80 General Business District - With central sewage the minimum lot drops to 40,000 sq ft, with or without central water, and the front, side and rear setbacks fall to 25 ft. Where the lot abuts a residential district boundary, add 25 ft to the side and rear yards.
- Central sewage also lifts the coverage cap to 40% and cuts the minimum width to 125 ft and the minimum depth to 175 ft.
- The minimum lot area is also the land required for each dwelling unit.
M-3 Mountain District - Where the lot abuts a residential district boundary, the side and rear yards go up by 25 ft; the figures shown are for a lot that does not abut one. The lot area shown is also the land required per dwelling unit.
- The schedule prints the same standards in all four of its utility columns, so these figures do not change where central water or central sewage is available.
ADUs vs. short-term rentals in Plattekill
Short-term rentals allowed with local rules for Town of Plattekill. A short-term rental here needs an annual town permit under Chapter 86, adopted 10-15-2025 by L.L. No. 4-2025, and the chapter reaches every short-term rental, including one operating before it took effect (§ 86-1). 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 minimum1–1.5 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityCentral Hudson territory.
- Zoning codeshepstone.net/wp-content/uploads/2016/08/Plattekill.pdf
- Building dept(845) 883-7184
ADU FAQ — Plattekill, NY
Are ADUs allowed in Plattekill, NY?
Town of Plattekill has 8 districts. 5 districts allow ADUs with occupancy restrictions, 3 do not. Check your address with the free ADU checker, or confirm with the building department at (845) 883-7184.
Do I need a special permit for an ADU in Plattekill?
No district in Town of Plattekill requires a special-use permit for an ADU - 5 districts allow ADUs with occupancy restrictions, 3 do not. Site-plan review or a building permit may still apply.
Can I use an ADU as a short-term rental in Plattekill?
Short-term rentals allowed with local rules for Town of Plattekill. 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 Plattekill
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 Plattekill, priced by size.
How we know this
- Sections analyzed
- § 110-15I Accessory apartments; § 110-6C definition; § 110-10 and its Schedule of District Regulations (accessory uses column); § 110-11B
- Districts confirmed
- 8 of 8 — every mapped district.
- Last reviewed
- 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 Plattekill: 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 Plattekill 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) 883-7184 before relying on any answer. Source: the Offsite / Aldo zoning dataset.