ADU Rules: Alpharetta vs Roswell
How do adu rules rules compare between Alpharetta, GA and Roswell, GA?
Roswell has fewer restrictions than Alpharetta.
Alpharetta, GA
Fulton County
Accessory Dwelling Units in unincorporated Fulton County are permitted in residential zones with a maximum of 750 sq ft under Zoning Article 4. Atlanta amended its ADU rules in 2018 to allow ADUs in most R-zones.
View full Alpharetta rules →Roswell, GA
Fulton County
Roswell's Unified Development Code allows accessory dwelling units (ADUs) in limited residential zoning districts subject to size caps, owner-occupancy of the primary unit, and architectural-review standards. Garage conversions and second-floor apartments above garages are the most common forms.
View full Roswell rules →Key Facts Comparison
| Fact | Alpharetta | Roswell |
|---|---|---|
| County size cap | 750 sq ft | - |
| Owner occupancy | Required | - |
| Atlanta zones | R-5, R-4A, R-4B, PD-H | - |
| Authority | - | Roswell UDC residential districts |
| Typical Size Cap | - | 25% of primary residence |
| Owner Occupancy | - | Generally required |
| STR Use | - | Prohibited - residential STR ban applies |
| Permit | - | Building permit + architectural review |
Highlighted rows indicate differences between cities.
Alpharetta FAQ
Can I rent my ADU on Airbnb?
Only with STR license (Atlanta) — owner-occupancy still required.
Does an ADU need its own address?
Yes for utility/911 purposes; treated as a separate dwelling.
Roswell FAQ
Can I build an ADU in my Roswell backyard?
Only if the property's zoning district permits ADUs. Check the UDC's residential district article (Art. 3) or contact Community Development to confirm your zoning allows them.
Can I Airbnb my Roswell ADU?
No. The 2024 STR ordinance prohibits short-term rentals in residential zoning districts, which is where ADUs are allowed. ADUs must be owner-occupied or used as long-term rentals.
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