ADU Rules in Buffalo, NY (2026)
ADU rules, permit requirements, size limits, and fees for Buffalo, NY. Source-cited from official municipal code.
Yes, ADUs are allowed in Buffalo, NY.
Buffalo, 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 Buffalo, the Buffalo Office of Strategic Planning — Building Inspection Division handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Buffalo.
ADU Size Limits
ADU Size Limits in Buffalo: Detached ADU: up to 900 sq ft (max height: 20 feet). Attached ADU: 40% of primary dwelling floor area. Buffalo Green Code allows accessory dwelling units in N-1 residential zones. Maximum 900 sqft for detached ADUs. JADU is a California-specific concept — not applicable in Buffalo. Buffalo is fundamentally different from NYC in scale, density, housing market, and regulatory context.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 900 sq ft | 20 feet |
| Attached ADU | 40% of primary dwelling floor area | Per zone height limit |
Permit Fees
ADU Permit Fees in Buffalo: Plan check fee: $150–$600. Building permit fee: Based on construction value — typically $600–$2,500. Impact fees: None. School fees: None or N/A. Total estimated permit cost: $1,000–$4,000 total permit fees. Buffalo does not charge development impact fees for residential ADU scale projects. Buffalo's affordable land values make ADU construction economically accessible.
| Fee Type | Amount |
|---|---|
| Plan Check | $150–$600 |
| Building Permit | Based on construction value — typically $600–$2,500 |
| Impact Fees | None |
| School Fees | None |
| Total Estimate | $1,000–$4,000 total permit fees |
Permit Timeline
Buffalo ADU Permit Timeline: Buffalo Office of Strategic Planning building permit: typically 4-8 weeks for review. Online permit portal available. Construction 3-9 months. Apply through the Buffalo Office of Strategic Planning — Building Inspection Division online permit portal. Phone: (716) 851-5400.
Setback Requirements
ADU Setback Requirements in Buffalo: Front setback: follows zone standard. Side setback: 3 feet. Rear setback: 5 feet. Buffalo Green Code minimum ADU setbacks: 5 ft rear, 3 ft side. Buffalo's aging housing stock with many abandoned lots creates opportunities for rear-lot ADU construction.
Parking Requirements
Parking Requirements: 1 off-street parking space per ADU. Near NFTA Metro Rail stations or major bus routes, parking may be waived.
Restrictions & Requirements
- ADU must comply with Buffalo Green Code accessory use standards
- Only one ADU per single-family lot
- Cannot be separately conveyed from primary lot
- Must maintain minimum lot coverage per zone
- Historic preservation review in Allentown, Elmwood Village, and other designated areas
- Lead paint and asbestos remediation required for older properties — very common in Buffalo
How Many ADUs Are Allowed?
Number of ADUs Allowed in Buffalo: Single-family lots: 1. Multifamily properties: Multiple units in N-2R, N-3E, N-3R, and district zones per development standards. One ADU per single-family lot. Buffalo's abundant vacant lot inventory creates opportunities for new detached ADU construction beyond garage conversions.
Single-Family Lots
1
Multifamily Properties
Multiple units in N-2R, N-3E, N-3R, and district zones per development standards
Historic District Considerations
Historic District Requirements: Buffalo has 11 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. Buffalo has extraordinary architectural heritage for a post-industrial city. The work of Henry Hobson Richardson (Buffalo State Hospital), Louis Sullivan (Guaranty Building), Frank Lloyd Wright (Darwin D. Martin House — National Historic Landmark), Eliel and Eero Saarinen, and the City Beautiful Movement era all left significant marks. The Allentown Historic Preservation District is a large mixed-use neighborhood with Victorian-era commercial and residential buildings. The Richardson Olmsted Campus (former Buffalo State Hospital) is being adaptively reused as a hotel and cultural center. Buffalo's Preservation Board reviews exterior changes in locally designated historic districts. Look up historic district boundaries at: https://buffalony.gov/preservation
Frequently Asked Questions
Can I build an ADU in Buffalo?
Yes. Buffalo, NY allows accessory dwelling units. On a single-family lot you can build 1.
How big can an ADU be in Buffalo?
The maximum size for a detached ADU in Buffalo is 900 square feet.
How long does it take to get an ADU permit in Buffalo?
The typical ADU permit timeline in Buffalo is Buffalo Office of Strategic Planning building permit: typically 4-8 weeks for review. Online permit portal available. Construction 3-9 months.. Total estimated permit fees are $1,000–$4,000 total permit fees.
Do I need extra parking for an ADU in Buffalo?
No, Buffalo does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in Buffalo?
No, owner-occupancy is not required for ADUs in Buffalo.
Source: Buffalo Green Code (Unified Development Ordinance, 2017); NY Zoning Law. Last verified April 6, 2026. View source