How many ADUs have been filed in NYC?

261 distinct ADU projects have been filed with the NYC Department of Buildings and verified filing-by-filing against DOB records, as of July 31, 2026. That figure counts properties, not filings: one project can carry several DOB filings. The number is a floor, because filings that never use the word ADU in their description are not searched for.

Which borough has the most ADU projects?

Queens, with 164 of the 261 projects. The other four boroughs hold 97 between them: Staten Island 55, Bronx 24, Brooklyn 16, Manhattan 2.

What kinds of ADUs are New Yorkers building?

Attached 104, basement or cellar 80, detached 35, garage 33 and attic 6. Another 3 filings do not state a type. Attached and basement or cellar ADUs are the two most common, together about 70 percent of all projects.

Where does this ADU data come from?

NYC Department of Buildings job filings, published through NYC Open Data. Second Key verifies each one filing-by-filing against DOB records, using the filing description or the DOB NOW PW1 ADU declaration, and groups filings by property so a project is counted once. The map is refreshed monthly; it was last updated July 31, 2026.

The NYC ADU Project Map

Name: The NYC ADU Project Map
Creator: Second Key
License: https://www.secondkeynyc.com/

A free map of every ADU project filed with the NYC Department of Buildings, verified filing-by-filing against DOB records. 261 projects as of July 31, 2026. Updated monthly.

SECOND KEY · NYC ADU PROJECT MAP

Every verified ADU project in New York City

261 projects since the program opened · hover or tap a dot

one ADU project Showing all 261 verified ADU projects, updated July 31, 2026 Verified filing-by-filing against DOB records by Second Key · Source: NYC DOB filings via NYC Open Data

NYC ADU Project Map · Key Numbers

261

ADU projects across New York City, verified filing-by-filing against DOB records.

By boroughQueens 164 · Staten Island 55 · Bronx 24 · Brooklyn 16 · Manhattan 2

By ADU typeAttached 104 · Basement or cellar 80 · Detached 35 · Garage 33 · Attic 6 · Type not stated 3

Status60 have a DOB permit, 17 are approved and waiting on one and 184 are still in DOB review.

Median cost$176,520 as declared in DOB filings · 166 of the 261 projects state one

Last updated July 31, 2026. Source: NYC Department of Buildings filings via NYC Open Data.

Queens has 164 of the 261 projects, more than the other four boroughs together (97). Two types make up about 70 percent of them: 104 attached and 80 in a basement or cellar. Filing volume is rising, from 88 projects in 2025 to 169 in 2026 through July 31. Permits lag well behind. Of the 261, 60 have pulled a DOB permit and 184 are still in DOB review. DOB records show no certificate of occupancy for any of them yet.

How We Count

The source is NYC Department of Buildings job filings, published through NYC Open Data. Second Key reads every candidate filing and verifies it filing-by-filing against DOB records: either the filing's own description names an ADU, or the DOB NOW PW1 application answers that the scope of work includes one.

One property can carry several DOB filings, so this page counts distinct properties rather than filings — a property with three filings is counted once. A project enters the count if it was filed or reviewed as an ADU on or after June 1, 2025.

Declared construction cost is the number the applicant puts on the DOB filing, and it is usually lower than what the work costs to build. The count is a floor, not an audited figure: a filing from before the window opened whose description never uses the word ADU is not searched for, so projects like that are missing from the count.

What we deliberately do not publish: owner names, contact details, addresses and DOB job numbers. This page is compiled and verified by Second Key, a licensed New York City general contractor. It is not a City of New York product and is not affiliated with the Department of Buildings or HPD.

The rules that decide whether a property qualifies are in our NYC ADU eligibility guide, and our analysis of the filing data covers the trends behind the map.

Frequently Asked Questions

261 distinct ADU projects have been filed with the NYC Department of Buildings and verified filing-by-filing against DOB records, as of July 31, 2026. That figure counts properties, not filings: one project can carry several DOB filings. The number is a floor, because filings that never use the word ADU in their description are not searched for.
Queens, with 164 of the 261 projects. The other four boroughs hold 97 between them: Staten Island 55, Bronx 24, Brooklyn 16, Manhattan 2.
Attached 104, basement or cellar 80, detached 35, garage 33 and attic 6. Another 3 filings do not state a type. Attached and basement or cellar ADUs are the two most common, together about 70 percent of all projects.
Of the 261 verified projects, 60 have a DOB permit, 17 are approved and waiting on one and 184 are still in DOB review. DOB records show no certificate of occupancy for any of them yet. The program is young: the Zoning Resolution's definition of an ancillary dwelling unit (ZR 12-10) dates to December 5, 2024.
NYC Department of Buildings job filings, published through NYC Open Data. Second Key verifies each one filing-by-filing against DOB records, using the filing description or the DOB NOW PW1 ADU declaration, and groups filings by property so a project is counted once. The map is refreshed monthly; it was last updated July 31, 2026.