ADU Rules in New York City, NY (2026)
ADU rules, permit requirements, size limits, and fees for New York City, NY. Source-cited from official municipal code.
Yes, ADUs are allowed in New York City, NY.
New York City, NY permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In New York City, the NYC Department of Buildings (DOB) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in New York City.
ADU Size Limits
ADU Size Limits in New York City: Detached ADU: up to 1200 sq ft (max height: 20 feet). Attached ADU: No greater than existing primary dwelling floor area. NYC does not use the term JADU. Interior accessory apartments (basement/attic conversions) allowed in 1- and 2-family homes. Detached ADUs allowed as new construction. Maximum size follows NYC Zoning Resolution Article II. Specific size limits depend on lot area and FAR for the district.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 1200 sq ft | 20 feet |
| Attached ADU | No greater than existing primary dwelling floor area | Per primary dwelling zone height limit |
Permit Fees
ADU Permit Fees in New York City: Plan check fee: Plan examination fee varies by construction cost — approximately $200–$2,500. Building permit fee: Filing fee plus construction cost percentage — typically $500–$5,000. Impact fees: None. School fees: None or N/A. Total estimated permit cost: $1,000–$8,000 total permit fees. NYC DOB fee schedule: https://www.nyc.gov/site/buildings/business/fee-schedule.page. Penalty exemption program for certain existing illegal conversions converting to ADUs.
| Fee Type | Amount |
|---|---|
| Plan Check | Plan examination fee varies by construction cost — approximately $200–$2,500 |
| Building Permit | Filing fee plus construction cost percentage — typically $500–$5,000 |
| Impact Fees | None |
| School Fees | None |
| Total Estimate | $1,000–$8,000 total permit fees |
Permit Timeline
New York City ADU Permit Timeline: NYC DOB permits typically 3-6 months for plan examination. Expedited review available through NYC Development Hub. Construction 6-18 months. ADU Express program in development as of 2025. Apply through the NYC Department of Buildings (DOB) online permit portal. Phone: (212) 566-5000.
Setback Requirements
ADU Setback Requirements in New York City: Front setback: Per zoning district required front yard. Side setback: 8 feet. Rear setback: 30 feet. Required yards vary significantly by district. R1 and R2 require deep front yards (20-30 ft) and side yards. Rear yard minimum 30 ft in most low-density residential districts. Detached ADUs in rear yards must maintain required setbacks. City of Yes text amendment provides additional flexibility for ADUs added after September 30, 2025.
Parking Requirements
Parking Requirements: Parking requirements for ADUs waived citywide under City of Yes for Housing Opportunity (effective September 30, 2025). Previously ADUs in some districts required 1 additional space.
Restrictions & Requirements
- Owner must reside on property as primary residence
- ADU must comply with NYC Building Code habitability standards
- Basement/cellar ADUs must meet ceiling height minimums (7 ft minimum in habitable rooms)
- Fire safety and egress requirements must be met
- Landmark designation or historic district designation may limit alterations
- Rent stabilization may apply to new rental units in buildings with 6+ units
How Many ADUs Are Allowed?
Number of ADUs Allowed in New York City: Single-family lots: 1 ADU per 1-family dwelling lot. Multifamily properties: 1 ADU per existing unit for conversions; site-specific for new construction. City of Yes for Housing Opportunity (Dec 2024) allows: interior accessory apartments in 1- and 2-family homes, attached and detached ADUs on qualifying lots. Lots must meet minimum size thresholds which vary by district.
Single-Family Lots
1 ADU per 1-family dwelling lot
Multifamily Properties
1 ADU per existing unit for conversions; site-specific for new construction
Historic District Considerations
Historic District Requirements: New York City has 152 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. NYC Landmarks Preservation Commission (LPC) designated 152 Historic Districts and approximately 36,000 individual landmarks as of 2026. Any exterior alteration to a landmarked property or building in a historic district requires LPC Certificate of Appropriateness (CofA) or Staff-Level Approval. LPC reviews are public and can take 2-24 months for complex projects. Look up historic district boundaries at: https://www.nyc.gov/site/lpc/designations/designated-sites.page
Frequently Asked Questions
Can I build an ADU in New York City?
Yes. New York City, NY allows accessory dwelling units. On a single-family lot you can build 1 ADU per 1-family dwelling lot.
How big can an ADU be in New York City?
The maximum size for a detached ADU in New York City is 1,200 square feet.
How long does it take to get an ADU permit in New York City?
The typical ADU permit timeline in New York City is NYC DOB permits typically 3-6 months for plan examination. Expedited review available through NYC Development Hub. Construction 6-18 months. ADU Express program in development as of 2025.. Total estimated permit fees are $1,000–$8,000 total permit fees.
Do I need extra parking for an ADU in New York City?
No, New York City does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in New York City?
No, owner-occupancy is not required for ADUs in New York City.
Source: NYC Zoning Resolution Article II; City of Yes for Housing Opportunity Text Amendment (approved December 2024). Last verified April 3, 2026. View source