ADU · Columbia County

Can you build an ADU in Chatham, NY?

Village of Chatham has 6 districts. 3 districts prohibit ADUs, 3 require a special-use permit. Check your address to confirm the district that applies to your parcel:

Check my address for ADU feasibility → Free · no account needed to start

What the Chatham code says

An accessory dwelling is allowed only by special use permit from the Planning Board, and only in R, SR and C-2. There is no by-right route anywhere in the village, and the use is prohibited in C-1, C-3 and I.

Conditions the code attaches:

On a lot with less acreage than is required for two or more dwellings in the district, an accessory dwelling is limited to 700 square feet of floor area with a special use permit.
On a lot carrying the acreage for two dwellings, no floor area limit is stated; the unit must still be subordinate in size, location and appearance to the principal dwelling.
The unit may be attached, detached, or placed over an existing garage, subject to the maximum structure height (§ 110-5).
It must be independent of the principal dwelling, with complete living facilities including a kitchen.
No owner occupancy, kinship or age requirement applies to the unit.

What the Chatham 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
Residential (1- & 2-family)	0.17 ac	30 / 15 / 30 ft	35 ft	Special permit
Suburban Residential	0.34 ac	30 / 20 / 50 ft	35 ft	Special permit
Commercial 1	—	0 / 0 / 30 ft	40 ft	No
Commercial 2 (Church-Coleman)	0.17 ac	30 / 15 / 30 ft	35 ft	Special permit
Commercial 3 (Southern Gateway)	0.46 ac	30 / 20 / 50 ft	35 ft	No
Industrial	0.92 ac	50 / 30 / 30 ft	35 ft	No

Residential (1- & 2-family) - The lot minimum shown covers the first dwelling unit at 7,500 sq ft; a second unit requires another 2,500 sq ft. Residential coverage is capped by a formula rather than a flat percentage: 2,400 sq ft plus 25% of lot area up to 3 acres plus 5% of the area beyond 3 acres.

A multifamily dwelling needs 5,000 sq ft for the first unit plus 2,500 sq ft for each additional one, on a 100 ft lot, with 20 ft side and 40 ft rear yards and up to 3 storeys and 40 ft.
The residential coverage formula counts associated accessory uses along with the dwelling.
A nonresidential use requires 10,000 sq ft of lot area and 75 ft of lot width.
There is a floor as well as a ceiling on building height: minimum 1 storey, maximum 2 1/2 storeys.
In the Historic Overzone (HO), the density regulations of the underlying district apply.
Existing undersized lots are treated under § 110-47 and accessory structures and uses under § 110-24.

Suburban Residential - A two-family home needs 15,000 sq ft for the first unit plus 5,000 sq ft for the second, and residential coverage is set by a formula: 2,400 sq ft plus 25% of the lot area up to 3 acres plus 5% of the lot area beyond 3 acres, including accessory uses.

A nonresidential use takes 20,000 sq ft, with a minimum lot width of 100 ft.
The schedule sets a floor as well as a ceiling on height: minimum 2 storeys, maximum 2 1/2 storeys and 35 ft.
Existing undersized lots are handled under § 110-47.
Accessory structures and uses are governed by § 110-24.
The Historic Overzone (HO) applies the density regulations of the underlying district and adds no figures of its own.

Commercial 1 - For residential uses, including their accessory uses, lot coverage is capped at 2,400 sq ft plus 25% of the lot area up to 3 acres plus 5% of the lot area beyond 3 acres.

Buildings must be at least 2 storeys and no more than 3 storeys.
Minimum lot area and lot width are not required in C-1.
The front yard ranges from 0 to 10 ft for residential uses and is 0 ft for nonresidential uses, and it is reduced or enlarged to conform to neighbourhood conditions.
A parcel in the Historic Overzone follows the density regulations of the underlying district.
Existing undersized lots are covered by § 110-47, and accessory structures and uses by § 110-24.

Commercial 2 (Church-Coleman) - A nonresidential use needs 15,000 sq ft of lot on a 75 ft width, well above the residential minimum shown, and the coverage percentage shown is the nonresidential figure. Residential coverage runs off a formula instead.

Residential lot area is 7,500 sq ft for the first dwelling unit plus 2,500 sq ft for the second.
Residential coverage, including associated accessory uses, is capped at 2,400 sq ft plus 25% of the lot area up to 3 acres plus 5% of the lot area beyond 3 acres.
The schedule sets a minimum of 2 storeys as well as a maximum of 2 1/2 storeys and 35 ft, so there is a floor on building height as well as a ceiling.
The Historic Overzone (HO) applies the density regulations of the underlying district and adds no figures of its own.
Existing undersized lots are addressed at § 110-47, and accessory structures and uses at § 110-24.

Commercial 3 (Southern Gateway) - The lot size, width and coverage figures shown are the nonresidential standard. Residential uses, including associated accessory uses, are capped instead by a formula: 2,400 sq ft plus 25% of lot area up to 3 acres plus 5% of lot area beyond 3 acres.

A multifamily dwelling needs 5,000 sq ft for the first unit plus 2,500 for each additional, on a 100 ft lot, up to 3 storeys and 40 ft.
The schedule sets a floor as well as a ceiling on height: minimum 2 storeys, maximum 2 1/2 storeys and 35 ft.
More than one business may be allowed on a lot, with the number fixed when the special use permit is issued.
The Planning Board may modify the side yard setback on a multiple-use site.
The Historic Overzone (HO) applies the density regulations of the underlying district, so it adds no figures of its own.
Existing undersized lots are covered by § 110-47, and accessory structures and uses by § 110-24.

Industrial - The figures shown apply to nonresidential uses. For residential uses, including their accessory uses, lot coverage is capped at 2,400 sq ft plus 25% of the lot area up to 3 acres plus 5% of the lot area beyond 3 acres.

A parcel in the Historic Overzone follows the density regulations of the underlying district.
Existing undersized lots are covered by § 110-47, and accessory structures and uses by § 110-24.

ADUs vs. short-term rentals in Chatham

No local short-term-rental law on record - which is not the same as permission for Village of Chatham. The village has no confirmed short-term rental law of its own. The rule here is not confirmed, so check with the building department before counting on renting a home short term. 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 minimum0.17–0.34 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/29136282
Building dept(518) 392-5821

ADU FAQ — Chatham, NY

Are ADUs allowed in Chatham, NY?

Village of Chatham has 6 districts. 3 districts prohibit ADUs, 3 require a special-use permit. Check your address with the free ADU checker, or confirm with the building department at (518) 392-5821.

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

It depends on the district: 3 of 6 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 Chatham?

No local short-term-rental law on record - which is not the same as permission for Village of Chatham. 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 Chatham

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $195k–260k 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 Chatham, priced by size.

How we know this

Sections analyzed: 110 Attachment 1 (Table of Use Regulations) · § 110-5 · § 110-16
Districts confirmed: 6 of 6 — every mapped district.
Last reviewed: 2026-06-02
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 Chatham: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Columbia County · All Columbia County towns

ADU information for Village of Chatham is compiled from the municipal code (last reviewed 2026-06-02) 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 (518) 392-5821 before relying on any answer. Source: the Offsite / Aldo zoning dataset.