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ADU Rules in New York City, New York

Complete guide to building an Accessory Dwelling Unit in New York City — zoning, setbacks, permits, costs, and more.

Max Size: 800 sq ft of zoning floor area (ZR 12-10), which counts toward the lot's floor area ratio; a backyard ADU may also cover no more than one-third of the required rear yard (ZR 23-341(b)(4)), so a 500 sq ft footprint needs a 1,500 sq ft rear yard. Converting a garage or shed that existed before Dec 5, 2024 is not a 'backyard ADU' and is allowed even where new ones are barred. Setbacks: A free-standing backyard ADU may stand inside the required rear yard as a permitted obstruction but must be at least 5 ft from the rear lot line and cover no more than one-third of the rear yard (ZR 23-341(b)(4)). A converted pre-Dec 2024 garage may keep its existing non-complying position (DOB ADU Types page). Parking: Varies Verified: 2026-09-20

Researched by ADU Zoning Hub · verified 2026-09-20 against New York City planning code and New York ADU law · methodology · 24 sources cited ↓

ADU Score: 5/10
Moderately friendly · how we score

Are ADUs allowed in New York City, NY? [1][2][3][4][5][6][7][8]

Yes. New York City allows ADUs on most residential lots. A detached unit can be up to 800 sq ft, set 5 ft back from the rear line. Parking varies by lot and unit size. Owner-occupancy rules vary — confirm with the city. A building permit is required and applications are reviewed through the standard permit process.

Maximum size800 sq ft of zoning floor area (ZR 12-10), which counts toward the lot's floor area ratio; a backyard ADU may also cover no more than one-third of the required rear yard (ZR 23-341(b)(4)), so a 500 sq ft footprint needs a 1,500 sq ft rear yard. Converting a garage or shed that existed before Dec 5, 2024 is not a 'backyard ADU' and is allowed even where new ones are barred.
SetbacksRear A free-standing backyard ADU may stand inside the required rear yard as a permitted obstruction but must be at least 5 ft from the rear lot line and cover no more than one-third of the rear yard (ZR 23-341(b)(4)). A converted pre-Dec 2024 garage may keep its existing non-complying position (DOB ADU Types page). · Side 5 ft minimum from any side lot line for a free-standing backyard ADU (ZR 23-341(b)(4)). The unit must also be reachable from the street by a side yard or open strip at least 5 ft wide (ZR 12-10), which DOB and FDNY enforce as a clear 5 ft access path; this rules out most attached row houses.
ParkingNone. The parking requirement for an ancillary dwelling unit is 0 percent in every district (Column B of the ZR 25-222 and 25-232 tables), and a garage converted to an ADU need not replace the lost space where zoning permits (DOB ADU FAQ).
Owner-occupancyAt the time the ADU is first occupied, the zoning lot must be the primary residence of an owner of that lot (ZR 12-10(f); 1 RCNY 105-08(d)(2)); DOB may require the proof of primary residence listed in 19 RCNY 46-03. The code writes no continuing owner-occupancy requirement after that point; a Plus One ADU loan adds its own 15-year regulatory agreement.

Do I need a permit to build an ADU in New York City? [9][10][11][12][13][14]

Yes. Every ADU in New York City needs a building permit. Review process: File in DOB NOW: Build (ADU filings accepted since September 30, 2025): an Alt-CO-GC job for a unit inside the house, or a New Building-GC job for a detached or fire-wall-separated unit, answering the Ancillary Dwelling Unit questions on the PW1. A NYS-licensed architect or engineer files; detached ADUs get their own BIN, house number and Certificate of Occupancy (1 RCNY 105-08(e))..

Permit feesDOB filing fee (Admin. Code 28-112.1): a detached ADU filed as a New Building pays $0.06 per sq ft with a $100 minimum, so $100 for 800 sq ft; an interior conversion filed as an Alt-CO pays $170 for the first $5,000 of work plus $2.60 per $1,000 above that (about $550 on a $150,000 job).
Typical timelineDOB publishes no ADU-specific review time. ADU jobs may be filed Professionally Certified by the architect (DOB ADU FAQ), except pilot-program legalizations; HPD's ADU guidebook puts design-to-completion at two months to two and a half years depending on the ADU type.
Official New York City links:

Three things to know before you build in New York City

  • Check your lot first: HPD's free ADU for You Eligibility Lookup Tool (housing.hpd.nyc.gov/adu) reads your zoning district, flood status and rear yard; new backyard ADUs are barred in R1-2A, R2A and R3A outside the Greater Transit Zone, in historic districts and in DEP's flood risk areas, but converting a garage that stood before December 5, 2024 is allowed even there
  • Two-family owners: an attic, basement, cellar or attached ADU turns the house into a three-family Multiple Dwelling Law building (R-2 occupancy) with far heavier requirements; a detached unit or one separated by a masonry fire wall keeps R-3 status
  • Every ADU needs its own entrance, separate heating, cooling, electric and gas shutoffs, emergency escape openings in every habitable room, and sprinklers except in an above-grade unit inside a one-family home (attic units are always sprinklered) per Building Code Appendix U

Last verified 2026-09-20 against New York City planning code. How we verify

Yes: since City of Yes for Housing Opportunity (adopted December 5, 2024) any New York City lot with a one- or two-family home may add one "ancillary dwelling unit" of up to 800 sq ft of zoning floor area, in an attic, basement, cellar, garage, addition or a new backyard building (Zoning Resolution 12-10). A new backyard ADU is limited to one story and 15 ft, one-third of the required rear yard and 5 ft from the rear and side lot lines (ZR 23-341), needs no parking (ZR 25-222), and is barred in LPC historic districts, in R1-2A, R2A and R3A outside the Greater Transit Zone, and in DEP's flood risk areas; basement and cellar units are barred in those flood areas too. An owner must use the lot as a primary residence when the ADU is first occupied. Construction is governed by Local Laws 126 and 127 of 2024 (Building Code Appendix U) and filed in DOB NOW since September 30, 2025; the DOB filing fee is $100 for an 800 sq ft detached unit, but sprinklers, a separate entrance and a licensed architect or engineer are required, and outer-borough builds run about $100,000 for a basement conversion to $450,000 for a new backyard unit.

NYC Accessory Apartment & ADU Overview

New York City's accessory apartment rules have undergone a major transformation. The City of Yes zoning reform, adopted in December 2024, expanded ADU eligibility across all five boroughs — Manhattan, Brooklyn, Queens, the Bronx, and Staten Island. Under the new NYC accessory apartment rules, homeowners in qualifying residential zones can create accessory dwelling units through basement conversions, garage conversions, and in some cases new detached structures.

ADU Manhattan: Manhattan has the most limited ADU opportunities due to high-density zoning, but owners of townhouses and brownstones in residential zones (R1-R5) may qualify for accessory apartment conversions. The most common path is converting a basement or cellar level into a legal dwelling unit. Brooklyn ADU rules and Queens offer significantly more opportunities due to larger lot sizes and lower-density zoning.

Building an ADU in Brooklyn: Brooklyn has become the epicenter of NYC's ADU movement. Neighborhoods like Bay Ridge, Dyker Heights, Bensonhurst, Flatlands, East New York, and Canarsie have the highest concentration of ADU-eligible properties. Basement ADU conversions are the most popular option, with typical costs of $80,000-$150,000. The City of Yes ADU provisions removed many of the barriers that previously prevented Brooklyn homeowners from legalizing accessory apartments.

Important reality check: While headlines celebrated City of Yes as a blanket ADU legalization, eligibility is narrower than widely reported. Only about 12% of NYC residential lots currently meet the zoning, lot size, and dimensional requirements for ADUs. Applications opened in September 2025, and the city is still processing early submissions. A basement legalization pilot has run in East New York and selected neighbourhoods, but its application window has opened and closed more than once and DOB rulemaking is still in progress — verify the current status on nyc.gov/buildings before relying on it, and be aware HPD has warned about scams targeting basement-apartment owners.

NYC ADU legalization in 2026 continues to evolve as the city implements the City of Yes framework. Key changes include streamlined DOB approval processes, reduced parking requirements, and new pathways for legalizing previously unpermitted basement apartments. Owner-occupancy is required — you or a family member must live in either the primary home or the ADU. Whether you call it an accessory apartment, an ADU, or a granny flat — verify your specific property's eligibility before investing in plans.

Zoning & Size Requirements [1][2][3][4][5][6][7][8]

Yes — New York City allows ADUs. A detached ADU can typically be up to 800 sq ft under current New York and New York City zoning rules.

See what this means for your lot — ask New York City ADU builders for a quote →

Allowed ZonesAny zoning lot with a one- or two-family home where residential use is permitted: the ZR 12-10 definitions of single- and two-family residence (amended Dec 5, 2024) include an ADU, and Use Group II (ZR 22-121) allows those homes in every Residence District R1-R12. New backyard ADUs are barred in R1-2A, R2A and R3A outside the Greater Transit Zone, in LPC historic districts and in the Special Bay Ridge District; backyard, basement and cellar ADUs are barred in DEP's flood risk areas.
Max Size (Detached)800 sq ft of zoning floor area (ZR 12-10), which counts toward the lot's floor area ratio; a backyard ADU may also cover no more than one-third of the required rear yard (ZR 23-341(b)(4)), so a 500 sq ft footprint needs a 1,500 sq ft rear yard. Converting a garage or shed that existed before Dec 5, 2024 is not a 'backyard ADU' and is allowed even where new ones are barred.
Max Size (Attached)800 sq ft of zoning floor area whether the unit is in an attic, basement, cellar, horizontal or vertical addition, or attached garage (ZR 12-10). Cellar ADUs need ceilings at least 2 ft above grade and 7 ft of ceiling height in every habitable room (DOB ADU FAQ; BC Appendix U).
Max Size (JADU)No junior ADU category exists in NYC zoning; the 800 sq ft ancillary dwelling unit is the only accessory unit type, and only one is allowed per one- or two-family home on a zoning lot (ZR 12-10).
Max HeightA backyard ADU on a detached, semi-detached or zero-lot-line lot: one story and 15 ft, measured to the top of the roof; two stories and 25 ft where an accessory parking space sits beneath the unit (ZR 23-341(b)(4)). The rest of the house keeps the district's normal height rules.
Max UnitsOne ADU per one- or two-family residence on the zoning lot (ZR 12-10; 1 RCNY 105-08(d)(1)), and DOB allows no more than one ADU per tax lot. A two-family home adding an attic, basement, cellar or attached ADU becomes a three-family building under the state Multiple Dwelling Law unless a masonry fire wall separates the ADU (DOB ADU page; BC U203).

Setback Requirements [1][2][3][4][5][6][7][8]

New York City requires a rear setback of about 5 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is set by local rules (confirm with the city).

Rear SetbackA free-standing backyard ADU may stand inside the required rear yard as a permitted obstruction but must be at least 5 ft from the rear lot line and cover no more than one-third of the rear yard (ZR 23-341(b)(4)). A converted pre-Dec 2024 garage may keep its existing non-complying position (DOB ADU Types page).
Side Setback5 ft minimum from any side lot line for a free-standing backyard ADU (ZR 23-341(b)(4)). The unit must also be reachable from the street by a side yard or open strip at least 5 ft wide (ZR 12-10), which DOB and FDNY enforce as a clear 5 ft access path; this rules out most attached row houses.
Front SetbackNot applicable: a backyard ADU is a rear-yard building (ZR 12-10, 23-341) and the house's front yard rules (ZR 23-321) are unchanged. A detached ADU must also stand at least 10 ft from the main house (ZR 23-371(b)).
Parking RequiredNone. The parking requirement for an ancillary dwelling unit is 0 percent in every district (Column B of the ZR 25-222 and 25-232 tables), and a garage converted to an ADU need not replace the lost space where zoning permits (DOB ADU FAQ).
Owner OccupancyAt the time the ADU is first occupied, the zoning lot must be the primary residence of an owner of that lot (ZR 12-10(f); 1 RCNY 105-08(d)(2)); DOB may require the proof of primary residence listed in 19 RCNY 46-03. The code writes no continuing owner-occupancy requirement after that point; a Plus One ADU loan adds its own 15-year regulatory agreement.
Min Lot SizeNo minimum lot size or lot width is written for an ADU. What limits a backyard ADU is the rear yard: the unit may cover at most one-third of the required rear yard and needs a 5 ft side access path (ZR 12-10, 23-341); interior units are limited only by the 800 sq ft cap and the lot's remaining floor area.

Permit Process & Fees [9][10][11][12][13][14]

An ADU permit in New York City goes through a standard permit review. DOB publishes no ADU-specific review time. ADU jobs may be filed Professionally Certified by the architect (DOB ADU FAQ), except pilot-program legalizations; HPD's ADU guidebook puts design-to-completion at two months to two and a half years depending on the ADU type. Permit fees: DOB filing fee (Admin. Code 28-112.1): a detached ADU filed as a New Building pays $0.06 per sq ft with a $100 minimum, so $100 for 800 sq ft; an interior conversion filed as an Alt-CO pays $170 for the first $5,000 of work plus $2.60 per $1,000 above that (about $550 on a $150,000 job).

Approval ProcessFile in DOB NOW: Build (ADU filings accepted since September 30, 2025): an Alt-CO-GC job for a unit inside the house, or a New Building-GC job for a detached or fire-wall-separated unit, answering the Ancillary Dwelling Unit questions on the PW1. A NYS-licensed architect or engineer files; detached ADUs get their own BIN, house number and Certificate of Occupancy (1 RCNY 105-08(e)).
Review TimelineDOB publishes no ADU-specific review time. ADU jobs may be filed Professionally Certified by the architect (DOB ADU FAQ), except pilot-program legalizations; HPD's ADU guidebook puts design-to-completion at two months to two and a half years depending on the ADU type.
Permit FeesDOB filing fee (Admin. Code 28-112.1): a detached ADU filed as a New Building pays $0.06 per sq ft with a $100 minimum, so $100 for 800 sq ft; an interior conversion filed as an Alt-CO pays $170 for the first $5,000 of work plus $2.60 per $1,000 above that (about $550 on a $150,000 job).
Impact FeesNone. New York City levies no development impact fee; beyond the DOB filing fee, expect a DEP site-connection permit for new water or sewer lines and a higher property tax assessment once the unit is on the Certificate of Occupancy (HPD ADU guidebook).
Plan CheckStandard plan examination, or Professional Certification by the architect or engineer (DOB ADU FAQ). For a pre-approved plan, DOB's review is limited to site-specific items such as zoning analysis, foundations and utility connections (DOB OTCR page).
Pre-Approved PlansYes: DOB's OTCR list shows 8 pre-approved backyard ADU designs from 6 design firms (September 2026), reviewed by DOB for code and zoning and by FDNY for sprinklers, and browsable in HPD's ADU for You Plan Library; the design firm still files a site-specific job.

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Construction Costs [15][16][17]

Building an ADU in New York City typically costs $150,000-$450,000 ($300-$580 per sq ft); a garage conversion runs $150,000-$280,000.

See what this means for your lot — ask New York City ADU builders for a quote →

Average Build Cost$150,000-$450,000
Cost per Sq Ft$300-$580
Garage Conversion$150,000-$280,000
Prefab ADU (Installed)$220,000-$450,000

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Rental Income Potential [18][19][20][21]

A 2-bedroom ADU in New York City rents for around $2,900-$4,000/mo, an estimated 7-15% gross rental yield on a $220,000-$450,000 backyard build at $2,500-$3,400/mo; a $100,000-$230,000 basement conversion renting at one-bedroom rates can gross 13-30% (before taxes, vacancy, insurance and financing; a.

Avg Rent (1 Bedroom)$2,500-$3,400/mo
Avg Rent (2 Bedroom)$2,900-$4,000/mo
Short-Term RentalNo, unless you live in the ADU yourself while hosting: stays under 30 days require Local Law 18 of 2022 registration with the Office of Special Enforcement, a host present and at most two guests (HPD ADU guidebook, Ch.
Est. Annual ROI7-15% gross rental yield on a $220,000-$450,000 backyard build at $2,500-$3,400/mo; a $100,000-$230,000 basement conversion renting at one-bedroom rates can gross 13-30% (before taxes, vacancy, insurance and financing; a.

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Recent Law Changes

What's Changed Recently

  • April 9, 2026: DOB began accepting filings for a new one-family house built with a cellar ADU under 1 RCNY 105-08(d)(4) and Local Law 80 of 2026; the Local Law 126 basement and cellar legalization pilot is still not taking applications until DOB promulgates its rule (DOB ADU page, revised 04/09/26)
  • June 12, 2026: HPD closed intake for the Plus One ADU Program (up to a $220,000 HPD loan plus a $175,000 HCR grant per the program term sheet, so up to $395,000 combined); a mailing list is open for the next round
  • September 30, 2025: ADU filings opened in DOB NOW: Build; Local Laws 126 and 127 of 2024 (Building Code Appendix U) took effect June 16, 2025
  • December 5, 2024: City of Yes for Housing Opportunity adopted: 'ancillary dwelling unit' defined in ZR 12-10 (800 sq ft, one per one- or two-family home, owner primary residence at initial occupancy), backyard ADU height, rear-yard and 5 ft lot-line rules in ZR 23-341, 10 ft building separation in ZR 23-371, 0 percent parking in ZR 25-222 and 25-232
  • Pre-Approved ADU Plan Library: 8 DOB- and FDNY-reviewed backyard designs listed by DOB's Office of Technical Certification and Research as of September 2026
  • New York State has no statewide ADU mandate; NYC's rules come from the Zoning Resolution and Local Laws 126 and 127 of 2024

Tips for Building an ADU in New York City

  • Check your lot first: HPD's free ADU for You Eligibility Lookup Tool (housing.hpd.nyc.gov/adu) reads your zoning district, flood status and rear yard; new backyard ADUs are barred in R1-2A, R2A and R3A outside the Greater Transit Zone, in historic districts and in DEP's flood risk areas, but converting a garage that stood before December 5, 2024 is allowed even there
  • Two-family owners: an attic, basement, cellar or attached ADU turns the house into a three-family Multiple Dwelling Law building (R-2 occupancy) with far heavier requirements; a detached unit or one separated by a masonry fire wall keeps R-3 status
  • Every ADU needs its own entrance, separate heating, cooling, electric and gas shutoffs, emergency escape openings in every habitable room, and sprinklers except in an above-grade unit inside a one-family home (attic units are always sprinklered) per Building Code Appendix U
  • Basement and cellar units need 7 ft ceilings, a cellar ceiling at least 2 ft above grade, water sensors, 1-hour fire separation and DOHMH-certified radon and vapor mitigation, and are prohibited in the special flood hazard area and DEP's 10-year rainfall and coastal flood risk areas
  • The Local Law 126 legalization pilot for existing basement and cellar apartments (15 community districts, units occupied before April 20, 2024, applications due by April 20, 2029) is not yet accepting Authorization for Temporary Residence applications; HPD warns that anyone charging to 'file' for it is not affiliated with the city
  • Plus One ADU intake closed June 12, 2026 after thousands of responses; eligible owners (up to 165% AMI, owner-occupant, current on mortgage and city bills, outside the coastal risk district) may get up to $220,000 in HPD loans at 5% or less over 15-30 years plus a $175,000 state grant, in exchange for a 15-year regulatory agreement
  • Cost basis: 2026 industry guides for Queens and the outer boroughs put a basement conversion at $80,000-$230,000, a garage conversion at $150,000-$280,000 and a new backyard unit at $220,000-$450,000 ($300-$580 per sq ft); a factory-built unit still needs a foundation, utility connections, sprinklers and DOB site approval, so budget as for a detached build. Rents: HUD FY2026 FMR for the New York metro is $2,655 (1BR) and $2,910 (2BR); Zumper's September 2026 Queens medians are $3,400 and $3,500
  • Renting: leases of 30 days or more fall under state and city landlord-tenant law; stays under 30 days require Local Law 18 registration, a host living in the unit and no more than two guests. Homes built before 1987 need an asbestos assessment before DOB issues the permit, and expect a property tax increase once the ADU is on the Certificate of Occupancy
  • Cost basis (2026-09-20 re-verification): short term allowed: No, unless you live in the ADU yourself while hosting: stays under 30 days require Local Law 18 of 2022 registration with the Office of Special Enforcement, a host present and at most two guests (HPD ADU guidebook, Ch. 8) | roi estimate: 7-15% gross rental yield on a $220,000-$450,000 backyard build at $2,500-$3,400/mo; a $100,000-$230,000 basement conversion renting at one-bedroom rates can gross 13-30% (before taxes, vacancy, insurance and financing; a Plus One-financed unit may carry rent restrictions)

ADU Builders in New York City

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Sources & References

All data on this page is sourced from official government records and verified market data. View our full methodology.

  1. NYC Zoning Resolution 12-10, definitions: ancillary dwelling unit, backyard ancillary dwelling unit, single- and two-family residence, Greater Transit Zone (amended 12/5/2024) Municipal Code — Accessed 2026-09-20
  2. NYC Zoning Resolution 23-341, Permitted obstructions in required rear yards (backyard ADU height, one-third rear yard, 5 ft lot-line rule) Municipal Code — Accessed 2026-09-20
  3. NYC Zoning Resolution 23-371, Standard minimum distance between buildings (10 ft to an ADU) Municipal Code — Accessed 2026-09-20
  4. NYC Zoning Resolution 22-121, Use Group II general use allowances Municipal Code — Accessed 2026-09-20
  5. NYC Zoning Resolution 25-222, Requirements where group parking facilities are provided (ADU parking 0 percent) Municipal Code — Accessed 2026-09-20
  6. Local Laws 126/127: Ancillary Dwelling Units — NYC Department of Buildings (revised 04/09/26) Planning Department — Accessed 2026-09-20
  7. Ancillary Dwelling Unit (ADU) Types — NYC Department of Buildings Planning Department — Accessed 2026-09-20
  8. FAQs: Ancillary Dwelling Units — NYC Department of Buildings Planning Department — Accessed 2026-09-20
  9. 1 RCNY 105-08, Ancillary Dwelling Units outside the Temporary Residence Program Municipal Code — Accessed 2026-09-20
  10. FAQs: Ancillary Dwelling Units — NYC Department of Buildings (filing, Pro-Cert, effective dates) Planning Department — Accessed 2026-09-20
  11. OTCR: Pre-Approved Ancillary Dwelling Unit (ADU) — NYC Department of Buildings Planning Department — Accessed 2026-09-20
  12. Local Law 56 of 2016, amending the Admin. Code 28-112.1 fee schedule (1-3 family new building and alteration fees) Municipal Code — Accessed 2026-09-20
  13. DOB Service Update: Permit Fees for One-, Two-, or Three-Family New Buildings and Alteration Applications (effective January 17, 2017) Planning Department — Accessed 2026-09-20
  14. ADU for You Guidebook — NYC HPD (process, timeline, costs, renting) Planning Department — Accessed 2026-09-20
  15. ADU for You Guidebook, Chapter 4: Budgeting For Your ADU — NYC HPD Planning Department — Accessed 2026-09-20
  16. Building an ADU in Queens, NYC: Eligibility, Costs & Plans (2026) industry — Accessed 2026-09-20
  17. ADU Cost in New York: NYC, Westchester & Statewide Pricing (updated September 2026) industry — Accessed 2026-09-20
  18. HUD Fair Market Rents FY2026, New York, NY HUD Metro FMR Area Government Data — Accessed 2026-09-20
  19. Zumper Queens, NY rent research (September 19, 2026) Market Data — Accessed 2026-09-20
  20. Zumper Brooklyn, NY rent research (September 19, 2026) Market Data — Accessed 2026-09-20
  21. ADU for You Guidebook, Chapter 8: Moving Into Your ADU (short-term rental rules, Local Law 18) — NYC HPD Planning Department — Accessed 2026-09-20
  22. Plus One Ancillary Dwelling Unit (ADU) Program — NYC HPD Planning Department — Accessed 2026-09-20
  23. Plus One ADU Program Term Sheet — NYC HPD Planning Department — Accessed 2026-09-20
  24. ADU for You: NYC's ADU resource hub (eligibility lookup, plan library, budgeting tool) — NYC HPD Planning Department — Accessed 2026-09-20

Frequently Asked Questions

Can I build an ADU in New York City?

Yes. ADUs are allowed in Any zoning lot with a one- or two-family home where residential use is permitted: the ZR 12-10 definitions of single- and two-family residence (amended Dec 5, 2024) include an ADU, and Use Group II (ZR 22-121) allows those homes in every Residence District R1-R12. New backyard ADUs are barred in R1-2A, R2A and R3A outside the Greater Transit Zone, in LPC historic districts and in the Special Bay Ridge District; backyard, basement and cellar ADUs are barred in DEP's flood risk areas. in New York City. The maximum size for a detached ADU is 800 sq ft of zoning floor area (ZR 12-10), which counts toward the lot's floor area ratio; a backyard ADU may also cover no more than one-third of the required rear yard (ZR 23-341(b)(4)), so a 500 sq ft footprint needs a 1,500 sq ft rear yard. Converting a garage or shed that existed before Dec 5, 2024 is not a 'backyard ADU' and is allowed even where new ones are barred.. Owner-occupancy: At the time the ADU is first occupied, the zoning lot must be the primary residence of an owner of that lot (ZR 12-10(f); 1 RCNY 105-08(d)(2)); DOB may require the proof of primary residence listed in 19 RCNY 46-03. The code writes no continuing owner-occupancy requirement after that point; a Plus One ADU loan adds its own 15-year regulatory agreement.

How much does an ADU cost in New York City?

ADU construction in New York City typically costs $150,000-$450,000. Garage conversions run $150,000-$280,000, and prefab ADUs cost $220,000-$450,000.

How much can I rent an ADU for in New York City?

Average ADU rents in New York City are $2,500-$3,400/mo for a 1-bedroom and $2,900-$4,000/mo for a 2-bedroom unit.

Do I need parking for an ADU in New York City?

None. The parking requirement for an ancillary dwelling unit is 0 percent in every district (Column B of the ZR 25-222 and 25-232 tables), and a garage converted to an ADU need not replace the lost space where zoning permits (DOB ADU FAQ).. Check with New York City planning department for the latest New York ADU parking rules, as many states have relaxed requirements in recent years.

How long does it take to get an ADU permit in New York City?

New York City does not publish a standard ADU review timeline. specific review time. ADU jobs may be filed Professionally Certified by the architect (DOB ADU FAQ), except pilot-program legalizations; HPD's ADU guidebook puts design-to-completion at two months to two and a half years depending on the ADU type. Permit fees: DOB filing fee (Admin. Code 28-112.1): a detached ADU filed as a New Building pays $0.06 per sq ft with a $100 minimum, so $100 for 800 sq ft; an interior conversion filed as an Alt-CO pays $170 for the first $5,000 of work plus $2.60 per $1,000 above that (about $550 on a $150,000 job).

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ADU Guides for New York City Homeowners

FAQ

New York City ADU FAQ

Answers to every common question about building an ADU in New York City — costs, rules, permits, rental income.

Read FAQ → Cost Guide

New York City ADU Costs

Detailed cost breakdown: construction $150,000-$450,000, garage conversion $150,000-$280,000, plus ROI analysis.

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Garage Conversion ADU Guide

Complete guide to costs ($80K-$180K), impact fee savings, and permits for garage-to-ADU conversions.

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ADU vs Mother-in-Law Suite

Legal differences that affect what you can build, how you can use it, and rental rights.

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About this information: This page is an informational summary of publicly available regulations - it is not legal, financial, or professional advice, and it is not a substitute for confirming requirements with your local planning department. Rules change frequently; always verify current requirements before designing, budgeting, or building. Last verified: 2026-09-20. Contractors we introduce are independent businesses - verify license and insurance directly before hiring. Spotted an error? Tell us - we verify against primary sources and correct quickly.

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