New York ADU Laws & Rules by City (2026)

Key New York ADU Laws

New York ADU Laws

No statewide ADU law. Unlike California, New York has no state mandate. ADUs are decided town by town, village by village, under municipal home rule (Town Law, Village Law, General City Law). The 2021–22 statewide proposal died in committee and the FY2023 budget mandate was withdrawn in February 2022.
The word matters. Outside New York City almost nobody says “ADU” — the local terms are accessory apartment, mother-daughter and in-law apartment. Search your town's code for those.
Long Island runs permit regimes, not bans. Several Suffolk and Nassau towns have had accessory-apartment permits for decades, typically with owner-occupancy, registration and renewal conditions. Suffolk County Health Services may also need to sign off on sanitary capacity.
NYC is its own universe — City of Yes changed what is allowed, but the cellar-versus-basement distinction still decides most basement conversions, and legalization programme status changes often.
There is grant money. New York State's Plus One ADU programme funds ADU construction through local administrators in participating municipalities.

New York Cities ADU Comparison

City	Max Size	Setbacks	Permit Fees	Build Cost	1BR Rent	Score
Buffalo	1,000 sq ft gross floor area; a detached unit must also be shorter and smaller-footprint than the principal building (Green Code UDO 6.1.2.B)	15 feet	$2,000-$3,500	$110,000-$220,000	$1,100-$1,500/mo	7/10
New York City	Up to 800 sq ft (and no more than 33% of the required rear yard) where permitted under City of Yes; not allowed in historic districts or R1-2A/R2A/R3A zones outside the Greater Transit Zone	N/A	$5,000-$10,000	$150,000-$300,000	$2,200-$3,200/mo	5/10
Rochester	Not applicable yet - the pending Zoning Alignment Project code would newly allow ADUs (by special permit in low-density zones); no adopted dimensional standards exist	15 feet	$1,900-$3,300	$105,000-$210,000	$1,050-$1,450/mo	2/10

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New York ADU Laws & Rules (2026)

Key New York ADU Laws

New York ADU Laws

New York Cities ADU Comparison

Get Free ADU Quotes in New York

Finance Your ADU Project

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