Georgia's booming Atlanta metro and historic coastal and university markets create strong ADU demand. City-by-city cost data across Atlanta, Savannah, and Athens — built from permit records, contractor data, and regional labor rates.
Illustrative 1-bedroom layout. Actual floor plans vary by ADU type, size, local code, and homeowner needs.
Unlike California, Oregon, or Massachusetts, no Georgia statute requires any city or county to allow accessory dwelling units. Whether you can build one — and what it can look like — depends entirely on which of Georgia's roughly 600 cities and 159 counties your property sits in. That makes "what are the rules" the first question here, not an afterthought.
2026 update — this almost changed. House Bill 1166 would have overridden local zoning statewide to allow a self-contained accessory unit up to 400 sq ft on any residential lot, with added protections barring institutional investors from adding ADUs to properties they own. It passed the Georgia House 111–50 on Crossover Day, March 6, 2026 — a wide margin — but the Senate never took it up before the legislature adjourned Sine Die on April 2, 2026. Georgia's zoning stayed exactly as fragmented as before. Watch for a reintroduction in a future session; a bill that clears the House by that margin tends to come back.
No broad statewide ADU siting mandate exists in Georgia as of this review — HB 1166 (2026) would have created one but died without a Senate vote. City, county, zoning, building, utility, and site rules control until or unless that changes.
Source: 2026 state housing-reform tracker → · Atlanta's current & proposed ADU rules →
These are planning benchmarks, not a permit quote, eligibility ruling, or legal opinion. Confirm zoning, building, utility, site, private-covenant, fee, and timing requirements with the current local authorities. See the 51-jurisdiction law directory and national permit guide.
Freestanding backyard structure with the highest rental income and property value uplift. Atlanta's zoning reforms have expanded eligibility citywide, pushing this toward the top of the range.
Detached ADU Guide →Uses an existing structure to cut cost significantly versus new detached construction while generating similar rental income in most Georgia markets.
Garage Conversion Guide →Factory-built construction offers a faster, more predictable timeline, with less exposure to Metro Atlanta's permitting backlogs and weather delays.
Prefab ADU Overview →Shares one wall with the primary residence. DeKalb County permits attached ADUs up to 900 sq ft, making this a strong option for smaller in-town lots.
Attached ADU Guide →Fulton County's hilly terrain makes walkout basement conversions common and cost-effective, particularly for homes built into sloped lots.
Basement ADU Guide →Local control: Local rules control. No broad statewide ADU siting mandate was identified in this review. Atlanta permits detached ADUs only, and historic-district review adds another layer in older neighborhoods; other cities and counties set their own rules. Permit fees and review timing remain planning estimates until confirmed for the specific property.
Calculate My ROI →Georgia is already one of the more affordable states to build in — these moves push savings further and prevent the most common costly mistakes.
Calculate My ADU ROI →
Start with the ROI calculator. Free, no signup, no contractor pitch. Just the data.