ADU · Sullivan County
Can you build an ADU in Thompson, NY?
Town of Thompson has 8 districts. 5 districts prohibit ADUs, 3 allow them. Check your address to confirm the district that applies to your parcel:
What the Thompson 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 |
|---|---|---|---|---|
| Suburban Residential District | 0.92 ac | 50 / 20 / 50 ft | 30 ft | As of right |
| Rural Residential District (1) | 0.92 ac | 50 / 20 / 50 ft | 30 ft | As of right |
| Rural Residential District (2) | 2 ac | 50 / 20 / 50 ft | 30 ft | As of right |
| Highway Commercial District (1) | 0.46 ac | 40 / 25 / 50 ft | 35 ft | No |
| Highway Commercial District (2) | 0.46 ac | 40 / 25 / 50 ft | 35 ft | No |
| Conservation/Institutional District | 3 ac | 40 / 25 / 50 ft | 35 ft | No |
| Extractive District | 50 ac | 200 / 50 / 50 ft | 35 ft | No |
| Economic Business Growth District | 0.92 ac | 40 / 25 / 50 ft | 35 ft | No |
ADUs vs. short-term rentals in Thompson
No local short-term-rental law on record - which is not the same as permission for Town of Thompson. No specific STR local law found as of Jun 2026. Chapter 187 (Rental Property) governs traditional rentals, but no dedicated STR permitting ordinance has been identified as of Jun 2026. 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 minimum0.92–2 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityNYSEG territory.
- Building dept(845) 794-2500
- Last reviewed2026-08-16
ADU FAQ — Thompson, NY
Are ADUs allowed in Thompson, NY?
Town of Thompson has 8 districts. 5 districts prohibit ADUs, 3 allow them. Check your address with the free ADU checker, or confirm with the building department at (845) 794-2500.
Do I need a special permit for an ADU in Thompson?
No district in Town of Thompson requires a special-use permit for an ADU - 5 districts prohibit ADUs, 3 allow them. Site-plan review or a building permit may still apply.
Can I use an ADU as a short-term rental in Thompson?
No local short-term-rental law on record - which is not the same as permission for Town of Thompson. 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 Thompson
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $190k–250k 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 Thompson, priced by size.
More on Thompson: Full zoning for new construction · ADU build cost · House build cost · All Sullivan County towns
ADU information for Town of Thompson 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) 794-2500 before relying on any answer. Source: Offsite / Aldo zoning dataset, municipalData.js.