# Gwinnett County, GA — Permit Site Plans, Shed Exemptions, and the Accessory Building Setback Grid
Georgia's second-largest county processes tens of thousands of residential permits a year, and it has one of the cleaner rule sets for small structures in metro Atlanta: accessory buildings under 120 square feet skip the permit entirely. The moment you hit 121 square feet, the rules change — but the county's location plan requirements are homeowner-friendly in most of its incorporated cities.
Here's what you need to know before you start building.
Do You Need a Site Plan for a Small Permit in Gwinnett County?
For accessory structures: A building permit is required for any accessory building or structure 121 square feet or larger. Also required — regardless of size — if the structure includes electrical or plumbing.
For decks: Required regardless of size.
For pools, garages, and additions: Required. Site plan rules apply.
When a permit is required, the county wants an Accessory Building Location Plan (or equivalent site plan), drawn to scale — 1″=10′ or 1″=20′ — showing lot boundaries, the existing home, driveways, easements, and the proposed structure's footprint and setbacks.
The key threshold: Sheds and outbuildings under 120 square feet are fully exempt from permits in unincorporated Gwinnett. This exemption does not extend to structures with power or plumbing.
Gwinnett County's Sliding Setback Scale
This is the piece most people get wrong. Setbacks for accessory structures in Gwinnett County scale with the structure's size:
| Structure size | Minimum setback from property line |
|---|---|
| Under 120 sq ft (exempt) | 5 feet |
| 121–300 sq ft | 10 feet |
| 301–500 sq ft | 15 feet |
| Over 500 sq ft | 20 feet |
Accessory structures must also be located in the rear or side yard — front yard placement isn't allowed. And an accessory structure cannot exceed 50% of the primary dwelling's square footage or be used for commercial operations or human habitation.
Who Runs Into This in Gwinnett County
Gwinnett's mix of newer subdivisions and established communities generates steady permit traffic from:
- Sugar Hill and Buford homeowners building detached garages and pool houses on larger suburban lots
- Lawrenceville contractors pulling shed and deck permits for renovation clients
- Duluth and Norcross homeowners adding backyard structures to smaller infill lots where setback math is tight
- Snellville owner-builders who benefit from the city's explicit acceptance of non-professional location plans
- Chattahoochee River Corridor property owners whose projects trigger impervious surface calculations within the corridor
What Needs a Site Plan in Gwinnett County
Every project type below triggers the Accessory Building Location Plan requirement once it hits the permit threshold:
- Fence permit site plan — Fences over 4 feet in front yards or 6 feet in rear/side yards may require approval. HOA restrictions often add layers — confirm before starting.
- Shed permit site plan — Under 120 sq ft: no permit needed. 121+ sq ft: permit plus location plan required. Setback rules above apply.
- Deck permit site plan — Requires a permit regardless of size. Plan must show footprint, height above grade, and setbacks.
- Pool permit site plan — Permit required. Accessory structure setback rules apply. Plan must show equipment location, barriers, and setbacks.
- ADU permit site plan — ADUs require a permit and a site plan showing footprint, setbacks, and parking.
- Garage permit site plan — Detached garages are accessory structures; permit plus location plan required. Setback rules apply.
- Addition permit site plan — Site plan must show existing house footprint, expanded footprint, and updated setbacks.
- Driveway permit site plan — May require a permit; site plan shows driveway location, right-of-way, and curb cuts.
Why This Trips People Up in Gwinnett County
The 120 sq ft line is exact — and commonly misunderstood. Many homeowners assume a "small shed" means no paperwork no matter what. In Gwinnett, 120 square feet exactly is the limit; 121 square feet triggers the full permit and location plan process.
Each of Gwinnett's 16 cities has its own rules. What works for a Snellville homeowner may not apply to a Duluth property. If your address falls within an incorporated city, that city's building department — not the county — issues your permit.
The Chattahoochee River Corridor. Properties within the corridor must show impervious square footage within that area on the site plan. This catches Gwinnett homeowners near the river off guard, especially in the Berkeley Lake and Duluth areas.
Legal lot of record requirement. Gwinnett County requires that "the lot upon which a building is located must be a legal lot of record." Before applying, confirm your property is recognized as a buildable lot.
City-by-City Notes in Gwinnett County
| City | What to know |
|---|---|
| Snellville | Explicitly allows non-professional location plans: "need not be prepared by a registered surveyor or engineer, but may be done by the individual proposing the improvements." |
| Lawrenceville | Confirmed city page live. Homeowners can serve as general contractor with a Homeowner Affidavit; permits require a House Location Plan (HLP). |
| Sugar Hill | Confirmed city page live. Accepts scaled site plans showing property lines and setbacks. |
| Berkeley Lake | Accepts homeowner-drawn site plans with actual lot dimensions, setback measurements, and building dimensions. |
| Duluth | Requires a site plan drawn in accordance with an accurate boundary line survey. |
| Buford | Accepts non-certified site plans; one-page sketch with dimensions often sufficient. |
| Norcross | Accepts homeowner-drawn plans for residential projects. |
> If your property is in an incorporated city, that city's building department handles your permit. Always confirm requirements before starting.
How the Tool Handles This — 5 Steps
SitePlans.ai loads Gwinnett County parcel data so you're working from your actual lot, not a blank canvas:
- Enter your address — The tool pulls your lot boundaries and building footprint from county records.
- Place your project — Drop your shed, deck, garage, or pool onto the real lot layout.
- Set the correct setback — The tool shows distances to property lines. Adjust based on your structure's size using the setback grid above.
- Mark easements and stream buffers — Add utility easements, drainage easements, and Chattahoochee Corridor boundaries where relevant.
- Export a scaled PDF — Download a dimensioned 1″=10′ or 1″=20′ plan ready for permit submission or professional review.
Where This Tool Fits — and Where It Doesn't
| Situation | Best path |
|---|---|
| Shed under 120 sq ft | No permit needed — but SitePlans.ai helps you confirm setback compliance before building |
| Shed 121+ sq ft, deck, or small accessory structure | SitePlans.ai for layout; homeowner-drawn plans accepted in Snellville, Lawrenceville, Sugar Hill, and others |
| Commercial or multi-family project | Georgia-registered engineer or architect required — seal mandatory |
| Property near Chattahoochee River Corridor | Include impervious area calculation on plan; verify buffer status |
| Property line dispute or unclear boundaries | Licensed land surveyor |
| Plan rejected by reviewer | SitePlans.us for human-reviewed revision, or engage a licensed professional |
What This Doesn't Replace
SitePlans.ai helps create preliminary, conceptual, permit-style site plans for smaller residential projects where local rules allow homeowner- or contractor-prepared drawings. It is not a licensed land survey, sealed engineering drawing, PE/PLS/architect stamp, or a guarantee of permit approval. In Gwinnett County, commercial and multi-family projects require sealed plans from a Georgia-registered professional. Where a jurisdiction requires a licensed professional's certification, that requirement must still be followed.
Comparison: Your Options for a Gwinnett County Location Plan
| Method | Cost | Time | Stamp | Notes |
|---|---|---|---|---|
| Hand sketch | Free | 30 min–2 hrs | ✗ | May be accepted for smaller residential projects in DIY-friendly cities |
| Generic floor plan app | Free–$50 | 1–3 hrs | ✗ | Usually lacks parcel data; you'll need to manually enter lot dimensions |
| SitePlans.ai | Free first plan | Minutes | ✗ | Pulls Gwinnett parcel data; produces scaled, titled plan; accepted in most residential permit offices |
| CAD drafter | $300–$800+ | 1–2 weeks | Sometimes | Better for complex projects or commercial work |
| Licensed surveyor/engineer | $500–$2,000+ | 1–3 weeks | ✅ | Required for commercial/multi-family; always valid for residential |
| SitePlans.us (done-for-you) | Custom | 1–3 days | ✗ (human-reviewed, non-certified) | Best for rejections, complex projects, or tight timelines |
Common Mistakes That Delay Gwinnett County Permits
- Assuming 120 sq ft sheds always need a permit — They don't, but 121+ sq ft does.
- Missing minimum setback — The setback jumps from 5 ft to 10 ft the moment you hit 121 sq ft.
- Placing structure in the front yard — Not allowed; rear or side yard only.
- No scale indicated — Plans must explicitly state 1″=10′ or 1″=20′.
- No north arrow — Required for orientation reference.
- No easements shown — Utility and drainage easements must appear on the plan.
- Not checking the city — Gwinnett County's permit office only covers unincorporated areas; if you're in a city, go to that city's building department.
- Chattahoochee Corridor not addressed — Properties within the corridor need impervious surface calculations.
Support and Local Resources
- Gwinnett County Planning & Development — gwinnettcounty.com — permits, plan review, zoning
- Gwinnett County GIS Data Browser — over 245,000 parcels across 2,300 miles of road
- Lawrenceville Building Permits — lawrencevillega.org/249/Building-Permits
- Georgia DCA Building Codes — dca.ga.gov
- FEMA Flood Map Service Center — msc.fema.gov
Nearby Counties
- Fulton County site plan guide
- DeKalb County site plan guide — Gwinnett's western neighbor
- Forsyth County site plan guide — North Gwinnett
- Hall County site plan guide — Northeast
- Walton County site plan guide — East Gwinnett
Frequently Asked Questions
1. What size shed requires a permit in Gwinnett County?
Any accessory structure 121 square feet or larger requires a building permit. Structures under 120 square feet are exempt — unless they contain electrical or plumbing, which requires a permit regardless of size.
2. What is an Accessory Building Location Plan and do I need one?
It's Gwinnett County's term for the site plan submitted with an accessory structure permit. It must be drawn to scale (1″=10′ or 1″=20′) and show lot boundaries, existing structures, driveways, easements, and the proposed structure. You need one whenever your project requires a permit.
3. What are the setback requirements for a shed in Gwinnett County?
Setbacks scale with size: 5 feet for structures under 120 sq ft, 10 feet for 121–300 sq ft, 15 feet for 301–500 sq ft, and 20 feet for structures over 500 sq ft. Accessory structures must be in the rear or side yard.
4. Can a homeowner draw their own site plan in Gwinnett County?
For residential projects in many of Gwinnett's cities — including Snellville, which explicitly allows it — yes. Snellville states the location plan "need not be prepared by a registered surveyor or engineer." Commercial and multi-family projects require a Georgia-registered professional's seal.
5. Do I need a permit for a deck in Gwinnett County?
Yes. Decks require a permit regardless of size. A site plan showing the deck footprint, height above grade, and setbacks is required.
6. Can an accessory structure in Gwinnett County be in the front yard?
No. Accessory structures must be located in the rear yard or side yard only.
7. What is the Chattahoochee River Corridor requirement?
Properties within the Chattahoochee River Corridor must include the impervious square footage within the corridor on their site plan. Check with the Planning & Development Department to confirm whether your property is within the corridor.
8. Can I use SitePlans.ai for a Gwinnett County permit?
Yes — for residential project layouts. The tool pulls Gwinnett County parcel data so you start from your real lot dimensions. Plans produced are accepted in many Gwinnett cities for homeowner-prepared location plans. Always confirm with your specific city's building department.
9. What happens if my project is in an incorporated city within Gwinnett County?
That city's building department handles your permit, not the county. Rules can differ significantly — Duluth requires plans "in accordance with an accurate boundary line survey," while Snellville allows homeowner-drawn plans.
10. What is SitePlans.us and when should I use it?
SitePlans.us is the human-reviewed, done-for-you service for when a project has been rejected, is complex, or has a hard deadline. Plans are reviewed by professionals and are non-certified; they serve as a permit-ready draft for building department review.
11. Does SitePlans.ai guarantee permit approval in Gwinnett County?
No. The tool produces preliminary, conceptual, permit-style plans. Approval depends on your building department's review, zoning compliance, HOA rules, and project completeness.
12. What if my property lines look wrong in SitePlans.ai?
Verify against Gwinnett County's GIS Data Browser. The GIS parcel data is an approximation — if boundaries look significantly off, consult a licensed land surveyor for your specific lot.
13. Can a contractor use SitePlans.ai for multiple client projects in Gwinnett County?
Yes. The Contractor Pro and Builder subscription tiers are built for exactly this — GCs, fence contractors, deck builders, and pool contractors pulling multiple permits per month.
14. What is the legal lot of record requirement?
Gwinnett County requires that any lot where a building permit is applied for must be a recognized legal lot of record. If your property was created by an informal split or doesn't appear on a recorded plat, confirm its status with the county before starting a permit application.
15. How is Gwinnett County different from DeKalb County for residential permits?
DeKalb County requires a Georgia-registered engineer or surveyor's stamp on every residential site plan — no homeowner-drawn plans accepted. Gwinnett County's residential rules allow homeowner-prepared location plans in many cities, and the permit exemption for sub-120 sq ft structures doesn't exist in DeKalb.
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