New builds, additions, and major renovations in Georgia trigger a tax reassessment via building permits. Assessors often overvalue new homes using the cost approach. Learn the January 1 timing rules and how to appeal within 45 days to lower your bill.
How New Construction Affects Property Tax Assessments in Georgia You just built your dream home, finished that kitchen expansion, or added a second story. Then the county sends you an assessment notice, and the number makes your stomach drop. If you're trying to understand how new construction property tax in Georgia actually works, you're not alone. The system is surprisingly opaque, and the stakes are real: a $500,000 new build in DeKalb County can mean $8,600 a year in property taxes, while the same home in Cobb might cost you $6,000. This guide breaks down how Georgia counties assess new construction, what triggers a reassessment (and what doesn't), the temporary billing rules that catch people off guard, and exactly how to appeal if the assessed value looks inflated. How Does Georgia Calculate Property Tax on New Construction? Georgia assesses all real property at 40% of fair market value under O.C.G.A. § 48-5-7. Fair market value means the price a knowledgeable buyer would pay a willing seller, with neither under pressure to close the deal (O.C.G.A. § 48-5-2). That 40% figure is called your assessed value, and it's what gets multiplied by the local millage rate to produce your tax bill. If you build a $500,000 home in a county with a blended 30-mill rate, the math looks like this: Fair market value: $500,000 Assessed value (40%): $200,000 Annual tax: $200,000 × 0.030 = $6,000 But millage rates vary dramatically by county. Here's what that same $500,000 new build costs across metro Atlanta: County Approx. Millage Rate Assessed Value Annual Tax -------- --------------------- ---------------- ------------ Fulton ~34 mills $200,000 ~$6,800 DeKalb ~43 mills $200,000 ~$8,600 Gwinnett ~34 mills $200,000 ~$6,800 Cobb ~30 mills $200,000 ~$6,000 That $2,600 gap between DeKalb and Cobb compounds every year you own the home. What Triggers…