Are ADUs Catching On in NYC? Here’s What the Data Says So Far
New York City's Accessory Dwelling Unit (ADU) program officially launched on September 30, 2025. For the first time, homeowners across the five boroughs can legally build backyard cottages and convert basements, garages, and attics into separate dwelling units.
The big question: are property owners actually building ADUs?
We analyzed every ADU filing submitted to the NYC Department of Buildings since the program launched, courtesy of Citytracker.ai, and what we found paints a fascinating early picture. The data shows a steady flow of about 16 filings per month, explosive momentum in Queens, and a clear preference in ADU configuration type.
Whether you're a Queens homeowner wondering if your neighbors are already planning an ADU project, or a Brooklyn property owner on the fence about whether it's worth the hassle, the data tells a story that NYC property owners need to hear.
What is an Accessory Dwelling Unit (ADU)?
An ADU is a secondary housing unit on a residential property. In New York City, the new ADU program allows 1- and 2-family homeowners to add a legal, self-contained dwelling unit to their property — complete with its own entrance, kitchen, and bathroom.
ADUs in NYC can take several forms:
Detached ADUs: A fully separate structure built in the backyard
Attached ADUs: A new addition built onto the rear, side or top of your home
ADU Garage Conversions: Transforming a detached or attached garage into living space
Subgrade ADUs: Converting a basement or cellar into a legal apartment
Attic ADUs: Finishing and converting attic space into a livable unit
The benefits are significant: rental income from a legal tenant, increased property value, housing for aging parents or adult children, and a contribution to New York's housing supply. New York City’s ADU program was created for 1- and 2-family homeowners — the backbone of housing in Queens, Staten Island, the Bronx and parts of Brooklyn.
NYC ADU Filings at a Glance
Here are the three most interesting highlights from the data:
Total ADU Filings: 94 (through March 6th, 2026)
Most Popular Borough For ADUs: Queens (66% of all ADU filings)
Most Popular ADU Type: Attached ADUs (54% of all ADU filings)
Insight #1: The NYC ADU Program Is Gaining Momentum
The city has received 94 total ADU project filings since June 6, 2025, which is considerable considering the program is brand new. Here's how filings have grown month by month:
October 2025 was the breakout month — the first full month after program launch — and filings have held steady in the mid-to-high teens ever since. At the current rate of 16 filings per month, NYC is on track for nearly 200 ADU applications in the program's first full year.
Insight #2: Queens is Dominating the ADU Market
It's not even close. Of the 94 ADU applications filed citywide, 62 came from Queens — accounting for nearly two-thirds of all filings in the city.
Queens accounts for nearly 4x more ADU applications than the next borough (Staten Island). This isn't surprising — Queens has the city's highest number of 1- and 2-family homes (over 246,000) — the exact housing stock that's eligible for the ADU program. Neighborhoods like South Ozone Park, Bayside, Jamaica, Flushing, Bayside, and Springfield Gardens are natural hotbeds for ADU activity.
Staten Island is ranked second, which is expected. Brooklyn's low number (just 7 filings) likely reflects its higher share of multi-family brownstones and attached rowhouses, which typically don't qualify. Manhattan has zero ADU filings — which tracks with our expectations. The city’s ADU zoning rules were written to spur low-scale development in the outer boroughs, not Manhattan.
Insight #3: Homeowners Prefer Attached ADUs
When it comes to what type of ADU NYC homeowners are building, attached additions lead the pack by a wide margin:
Attached ADUs — new additions built onto the side, rear or top of the house — are a clear favorite. We can extrapolate from the data that this could reflect homeowners maximizing square footage without sacrificing their backyard. Other reasons to choose an attached ADU for a single-family home - they are exempt from flood zone limitations and sprinkler requirements.
Basement conversions are a close second at 21%, which makes sense: NYC has a massive stock of underutilized basement space, and converting an existing structure is often faster and cheaper than building new. Garage conversions at 16% follow the same logic.
Detached ADUs — the classic "backyard cottage" — are surprisingly rare, at just 2 filings. NYC lot sizes are likely a major constraint; most city lots simply don't have enough rear yard space to accommodate a separate structure while meeting zoning setback requirements. As the ADU program gains popularity, we expect to see many more backyard cottages, especially in Staten Island.
Insight #4: ADUs Are Accessible at Many Price Points
One of the most encouraging findings in the data was that there is no single 'typical' ADU cost. Among the 68 filings that reported a project cost, spending is spread remarkably evenly across every budget range — from under $50,000 to over $1 million.
The right investment depends entirely on your property, your goals, and your timeline. The key insight from the data: NYC homeowners across the budget spectrum are moving forward with ADUs, not just deep-pocketed investors.
A Note on the Data
Small sample size: 94 filings is enough to identify trends, but patterns may shift as the program matures.
Approval isn’t guaranteed: there is a 3-6 month lag between filing date and approval date, and we anticipate some of the current filings will be rejected or withdrawn. We will provide periodic updates as filings move through the DOB plan review process.
Self-reported costs: Project costs are submitted by applicants and not verified at filing. They represent stated intent, not final construction spend. Further, for major alterations and new buildings with proposed ADUs, it’s impossible to identify how much of the construction costs are related specifically to construction of the ADU.
Data is sourced from Citytracker.ai, a search engine for NYC real estate that provides the latest data on filings, permits, and other property-specific documents. Analysis reflects filings through March 6th, 2026.
Thinking About an ADU on Your NYC Property?
The data is clear: New Yorkers are building ADUs, Queens is leading the pack, attached ADUs represent the preferred ADU type, and ADU costs vary from project to project. The question is whether you'll build one before your neighbors do.