ADU Rules: Buffalo vs Clarence
How do adu rules rules compare between Buffalo, NY and Clarence, NY?
Buffalo and Clarence have similar restriction levels.
Buffalo, NY
Erie County
Buffalo Unified Development Ordinance (Green Code) permits accessory dwelling units (ADUs) in most residential zones. ADUs must be on lots at least 2,500 sq ft, occupy no more than 800 sq ft, and meet parking and design standards. Owner-occupancy of the primary dwelling is required.
View full Buffalo rules →Clarence, NY
Erie County
Erie County does not zone for accessory dwelling units. Whether an ADU, in-law suite, or backyard cottage is allowed on your lot is decided by your town, city, or village zoning code, not by county government.
View full Clarence rules →Key Facts Comparison
| Fact | Buffalo | Clarence |
|---|---|---|
| Max size | 800 sq ft or 33% of main | - |
| Min lot | 2,500 sq ft | - |
| Owner-occupancy | Required | - |
| STR use | Prohibited | - |
| Code | Green Code UDO | - |
| Zoning authority | - | Your town, city, or village |
| County ADU ordinance | - | None (home rule) |
| State program | - | HCR Plus One ADU (voluntary) |
| Building standard | - | NYS Uniform Code / RCNYS |
Highlighted rows indicate differences between cities.
Buffalo FAQ
Can I convert my Buffalo double into a duplex plus an ADU?
In most N zones a two-family plus one accessory dwelling is allowed if lot area and parking support it. Consult the zoning administrator before designing.
Does the Green Code allow backyard cottages?
Yes. Detached ADUs are permitted in most residential N districts subject to size, setback, and height limits.
Clarence FAQ
Does Erie County allow ADUs?
Erie County has no ADU zoning. Whether an ADU is allowed is set by your town, city, or village. Check with your local zoning or building department for size, setback, and permit rules.
Did New York State legalize ADUs everywhere?
No. The state promotes ADUs through the voluntary HCR Plus One ADU grant program, but zoning approval still rests with each municipality, which controls whether and how ADUs may be built.
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