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ADU rules in New York

Representative cities: New York City, Buffalo.

Verify locally. New York uses the statewide Uniform Code / Residential Code of NY State, but New York City administers its own building code (filed by a NYS PE or RA). Buffalo and other cities follow the state code. Verify locally. ADU rules below are drawn from official sources — always confirm with the issuing building department before designing or building.

ADU permit rule

Permit requiredRestrictedcity authority
Fee basis
Permit and plan-review fees set by the city. Verify with the local building department.
Typical timeline
Varies by city; NYC ADU filings may take several weeks.
Setback
Per local zoning.
Area threshold
Allowed only where the local law permits.
Exempt if
None — where allowed, ADUs require a permit.
Go / no-go
restricted
New York has no statewide by-right ADU mandate; ADUs are allowed where local law permits (e.g., the NYC ADU program, Buffalo). Zoning applies.

Frequently asked questions

Do I need a permit to build an ADU in New York?

Per New York rules, an ADU is "yes" for a permit and the authority is "city". New York has no statewide by-right ADU mandate; ADUs are allowed where local law permits (e.g., the NYC ADU program, Buffalo). Zoning applies. Always confirm with the issuing building department.

How big can an ADU be in New York?

Area threshold: Allowed only where the local law permits.

What are the ADU setbacks in New York?

Setback: Per local zoning.

How much does an ADU permit cost in New York?

Fee basis: Permit and plan-review fees set by the city. Verify with the local building department.

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