ADU · Putnam County
Can you build an ADU in Putnam Valley, NY?
Town of Putnam Valley has 10 districts. 5 districts prohibit ADUs, 5 require a special-use permit. Check your address to confirm the district that applies to your parcel:
What the Putnam Valley 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 |
|---|---|---|---|---|
| Preservation District (min lot area is 10 acres of NET area and no minimum building area or road frontage is stated; minimum open area 98% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 2% of the gross site. Single-family dwellings are NOT a permitted use here. Maximum building length 50 ft. Rear yard on a lakefront lot is 120 ft) | 10 ac | 120 / 50 / 120 ft | 25 ft | No |
| Conservation District (5 acres NET, plus a 30,000 sf minimum BUILDING area and 300 ft of road frontage; minimum open area 90% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 10% of the gross site. Rear yard on a lakefront lot rises to 100 ft) | 5 ac | 100 / 40 / 100 ft | 35 ft | Special permit |
| Low Density Residence (3 acres NET, plus a 30,000 sf minimum BUILDING area and 200 ft of road frontage; minimum open area 85% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 15% of the gross site. Rear yard on a lakefront lot rises to 75 ft) | 3 ac | 50 / 40 / 50 ft | 35 ft | Special permit |
| Moderate Density Residence (2 acres NET, plus a 30,000 sf minimum BUILDING area and 200 ft of road frontage; minimum open area 75% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 25% of the gross site. Rear yard on a lakefront lot rises to 75 ft) | 2 ac | 50 / 40 / 50 ft | 35 ft | Special permit |
| Medium Density Residence (1 acre NET, plus a 20,000 sf minimum BUILDING area and 150 ft of road frontage; minimum open area 60% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 40% of the gross site. Rear yard on a lakefront lot rises to 75 ft. Maximum building length 100 ft) | 1 ac | 50 / 30 / 30 ft | 35 ft | Special permit |
| Lake Peekskill (2 acres NET, plus a 30,000 sf minimum BUILDING area, but only 75 ft of road frontage; minimum open area 75% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 25% of the gross site. Rear yard on a lakefront lot rises to 75 ft. Maximum building length 100 ft) | 2 ac | 50 / 20 / 30 ft | 35 ft | Special permit |
| Neighborhood Commercial (10,000 sf NET lot area, 80 ft of road frontage; no minimum building area and no minimum open area are set. Rear yard on a lakefront lot rises to 75 ft) | 0.23 ac | 25 / 20 / 25 ft | 35 ft | No |
| Community Commercial One (8,000 sf NET lot area — the smallest minimum in town — on 80 ft of road frontage; no minimum building area and no minimum open area are set. Rear yard on a lakefront lot rises to 75 ft) | 0.18 ac | 25 / 20 / 25 ft | 35 ft | No |
| Community Commercial Two (10,000 sf NET lot area, 80 ft of road frontage; no minimum building area and no minimum open area are set. Rear yard on a lakefront lot rises to 75 ft) | 0.23 ac | 25 / 20 / 25 ft | 35 ft | No |
| Planned Commercial Park (5 acres NET on 100 ft of road frontage, with the deepest front yard in town at 200 ft; minimum open area 70% — i.e. buildings, structures, paving and every other impervious surface together may cover no more than 30% of the gross site. Rear yard on a lakefront lot is 100 ft) | 5 ac | 200 / 100 / 100 ft | 35 ft | No |
ADUs vs. short-term rentals in Putnam Valley
Short-term rentals restricted for Town of Putnam Valley. Short-term transient rentals require a SPECIAL PERMIT: § 165-36.1 sits in Article X, Special Permit Uses, of the Zoning Code, added 11-15-2023 by L.L. No. 3-2023 and amended 4-16-2025 by L.L. No. 1-2025. The Town's stated intent is to impose mandatory requirements on every owner renting on a short-term transient basis, proportional to those on bed-and-breakfasts, inns, motels and hotels. Discretionary approval means an STR is not available as of right anywhere in the Town. New York State's 2025 short-term rental registry (Ch. 99 of the Laws of 2025) separately requires every host statewide to register the unit regardless of local law. Confirm with Town of Putnam Valley at (845) 526-2377 before listing. 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 minimum1–10 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityNYSEG territory.
- Building dept(845) 526-2377
- Last reviewed2026-07-22
ADU FAQ — Putnam Valley, NY
Are ADUs allowed in Putnam Valley, NY?
Town of Putnam Valley has 10 districts. 5 districts prohibit ADUs, 5 require a special-use permit. Check your address with the free ADU checker, or confirm with the building department at (845) 526-2377.
Do I need a special permit for an ADU in Putnam Valley?
It depends on the district: 5 of 10 require a special-use permit, the rest do not. Check the district that applies to your parcel before you design.
Can I use an ADU as a short-term rental in Putnam Valley?
Short-term rentals restricted for Town of Putnam Valley. 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 Putnam Valley
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $215k–285k 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 Putnam Valley, priced by size.
More on Putnam Valley: Full zoning for new construction · ADU build cost · House build cost · All Putnam County towns
ADU information for Town of Putnam Valley is compiled from the municipal code (last reviewed 2026-07-22) 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) 526-2377 before relying on any answer. Source: Offsite / Aldo zoning dataset, municipalData.js.