The subject of a new bill may be tiny by design, but the impact it’s sure to have on New York City will be large.
New York City has formally legalized tiny homes and small accessory dwelling units (ADUs) in contexts where they were previously banned or legally unclear, marking a major shift in how the city approaches housing production and affordability.
The law is aimed at New Yorkers who are interested in constructing their own tiny homes on their property, primarily in backyards. This originally became a possibility with former mayor Eric Adams’ “City of Yes” for Housing Opportunity package, in which he signed a zoning reform allowing certain one- and two-family homeowners to add an additional home or ancillary dwelling unit to their property. On September 30th, 2025, the city finalized rules for backyard and attic ADUs and began accepting applications, while rules for basement ADUs are still being developed.
This move could significantly boost housing access, with the city projecting up to 25,000 new homes over 15 years from backyard cottages and converted garages, attics, and basements—if homeowners can manage the high construction costs and regulatory requirements. The goal of City of Yes is to add tens of thousands of new homes and address the city’s ongoing housing crisis.
So how would one go about applying for and constructing an ADU, and who qualifies?
✅ ADU eligibility
- According to the FAQ section on NYC Gov’s website, only one ADU per one‑ or two‑family home is allowed, and the homeowner must live on the property as their primary residence at the time the ADU is first occupied.
- ADUs are limited to a maximum of 800 sq ft of floor area and must meet zoning and building code requirements, including separate entrances and various fire, safety, and utility standards under Appendix U of the NYC Building Code.
- Certain types of units are restricted or prohibited in specific areas — for example, backyard ADUs can’t be built in historic districts or certain low‑density zones, and basement or cellar ADUs are not allowed in high‑risk flood zones
🏡 Types of ADUs
- Backyard cottages: Standalone units in the rear yard where allowed by zoning
- Attic and garage conversions: These are treated as above‑grade ADUs but still subject to construction and safety codes
- Basement/cellar units: These can be created or legalized in some cases, but strict safety standards and flood restrictions apply, and related applications for legalization are still being phased in by the city
This comes alongside several other housing advancements in the city, including a bill aimed at increasing transparency around affordable housing units and a new database designed to make finding affordable housing easier. Together, these measures signal a broader push to expand housing opportunities, streamline access, and address the city’s affordability challenges.
For more information on ADU’s and how to create one, see NYC GOV’s official website.