ADU · Putnam County
Are ADUs allowed in Putnam County, NY?
There is no county-wide answer. In New York an accessory dwelling unit is governed by the town, city or village — so the rule changes at every municipal line, and often between districts inside one town. Below is each of the 9 municipalities in Putnam County, with what its zoning districts actually say.
- 9municipalities with mapped districts
- 8allow an ADU in at least one district
- 1allow one by right somewhere
ADU rules by municipality in Putnam County
Can you build an ADU in Carmel, NY?
10 districts prohibit ADUs, 2 allow them with occupancy restrictions.
Accessory dwelling units are allowed in the LDR and MDR districts only, one per property, and only inside an existing single-family dwelling or an accessory building that legally existed when the zoning chapter took effect. The owner must live in one of the two units.
Can you build an ADU in Kent, NY?
4 districts prohibit ADUs, 3 require a special-use permit.
In Kent, an accessory apartment needs a special use permit from the Zoning Board of Appeals under § 77-70, and it must be created inside an existing single-family dwelling. A detached accessory unit is not available anywhere in town.
Can you build an ADU in Patterson, NY?
5 districts allow ADUs with a special-use permit, 4 do not.
One accessory apartment is allowed inside an existing one-family home in Patterson with a special use permit under § 154-105. The owner has to live in one of the two units.
Can you build an ADU in Philipstown, NY?
8 districts allow ADUs with a special-use permit, 1 does not.
In RC, RR, HM, HR, SR, HC and OC, an accessory apartment is available by special permit under §§ 175-60 through 175-64. The code also describes circumstances where one may be permitted by right in those districts, but those conditions are not confirmed.
Can you build an ADU in Putnam Valley, NY?
5 districts prohibit ADUs, 5 require a special-use permit.
Where the use schedule lists an accessory apartment, it can be sought only with a special permit, not by right, and in other districts it is not a permitted use. A second unit should not be assumed for a given parcel.
Can you build an ADU in Southeast, NY?
12 districts prohibit ADUs, 5 require a special-use permit, 2 allow them.
Can you build an ADU in Brewster, NY?
9 districts prohibit ADUs, 1 requires a special-use permit.
An accessory single-family dwelling is allowed only in the R district, by special exception permit from the Board of Trustees. The owner has to live on the property.
Can you build an ADU in Cold Spring, NY?
8 districts prohibit ADUs, 4 require a special-use permit.
An accessory apartment is listed as a prohibited use in this district under Table 6A (§ 134-6.I). The use table names accessory apartments only for R-O, R-N, R-L and PMU.
Can you build an ADU in Nelsonville, NY?
All districts prohibit ADUs.
Nelsonville's zoning creates no accessory apartment or accessory dwelling use anywhere in the village, so an accessory unit is not something to count on here. Confirm with the village before planning one.
ADU questions people ask about Putnam County
Are ADUs allowed in Putnam County?
There is no single county-wide answer — ADUs are governed by each town, city and village, not by the county. Of the 9 Putnam County municipalities with mapped zoning districts, 8 allow an accessory dwelling unit in at least one district, and 1 allow one by right somewhere. The section for your municipality below gives the specific answer.
Does Putnam County issue ADU permits?
No. Zoning approval and building permits both come from the municipality — the town, city or village — not the county. County health departments do commonly review septic and water supply for a new dwelling unit, which is often the binding constraint on a rural lot.
What size ADU can I build in Putnam County?
Size caps are set per municipality and frequently per district, and they are one of the details most often stated wrongly by national ADU sites. Open your municipality's page below for the code sections analyzed, then confirm the current figure with the building department before you design to it.
What an ADU costs to build in Putnam County
Permission and budget are separate questions. See the Putnam County cost-to-build breakdown for current per-square-foot ranges — an accessory unit runs above a full house per square foot, because the kitchen, bath, panel and heating plant cost the same at any size.
More on Putnam County: Zoning for new construction by town · Cost to build · ADU rules across every county we cover
ADU information for Putnam County is compiled from each municipality's own code , most recently reviewed 2026-07-27, and provided for decision-support only — not legal or architectural advice. Eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; confirm with the municipality before relying on any answer. Source: the Offsite / Aldo zoning dataset.