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.
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:
But millage rates vary dramatically by county. Here's what that same $500,000 new build costs across metro Atlanta:
That $2,600 gap between DeKalb and Cobb compounds every year you own the home.
Not every project with a hammer and nails will change your tax bill. Georgia counties draw a clear line between improvements that add value and routine maintenance.
The mechanism is straightforward: when you pull a building permit, your county's building department forwards that permit to the Board of Tax Assessors (O.C.G.A. § 48-5-264.1). That's the assessor's cue to take a closer look. If you're planning a renovation and wondering whether it will affect your taxes, ask yourself: does it require a building permit? If yes, assume the assessor will know about it.
January 1 is the controlling date for all Georgia property tax assessments. Whatever condition your property is in at midnight on January 1 determines that year's taxable value.
This creates timing dynamics that catch people off guard:
Scenario 1: You finish construction in March. Your home was still under construction on January 1, so this year's assessment reflects a partially completed structure. The full value won't hit until next year's assessment cycle.
Scenario 2: You finish construction in November of the prior year. The home was complete on January 1, so this year's assessment captures the full value. Your first tax bill reflects the finished home.
Scenario 3: You're mid-renovation on January 1. The assessor values the property in its partially improved state. If you're adding a $100,000 addition that's 60% complete on January 1, expect the assessment to reflect roughly that proportion of added value.
Unlike California, Georgia doesn't issue supplemental tax bills for mid-year completions. You won't get a surprise bill six months after your certificate of occupancy. The adjustment waits until the next annual assessment cycle.
During the assessment and appeal process, Georgia uses a temporary tax bill system. For most properties, the temporary bill is the lesser of the prior year's tax or 85% of the current year's tax.
But there's a critical exception for new construction. If you have a homestead property with a building permit or structural improvements, the temporary bill defaults to 85% of the current year's assessed value. There's no prior-year comparison to cushion the blow, because the prior year didn't include the improvement.
This means your first tax bill after construction will be roughly 85% of what the county thinks you owe on the full value. If you're appealing, you still need to pay this temporary bill on time to avoid penalties.
For existing homes, assessors primarily use comparable sales to determine fair market value. For new construction, they lean heavily on the cost approach.
The cost approach works like this:
The result is the assessor's estimate of your home's fair market value. In theory, this should approximate what the market would pay. In practice, it often overshoots.
County assessors get new construction values wrong more often than you'd expect. In Gwinnett County, 49% of homes were overvalued in 2025 based on assessment-to-sale comparisons. In Fulton County, the figure was 41%. New construction is especially prone to overvaluation for several reasons.
Cost tables don't reflect your actual costs. Assessors use standardized cost manuals that estimate construction costs by region. These tables don't account for your specific contractor's pricing, bulk material discounts, or the fact that you acted as your own general contractor and saved 15%.
The “market adjustment” add-on. Some assessors tack on a percentage increase above documented construction costs to account for market appreciation. In the case study below, a Gwinnett County assessor added $52,500 beyond the actual renovation cost with no specific justification.
Square footage and feature errors. The assessor's property record card may list the wrong square footage, an extra bathroom, or materials you didn't use. These errors get baked into the cost calculation and inflate the result.
Land value overestimates. If the assessor's land value is based on peak-market vacant lot sales rather than current conditions, the entire assessment starts from an inflated baseline.
No depreciation applied to recent renovations. Even a renovation completed two years ago has some functional depreciation, but assessors frequently assign zero depreciation to anything recent.
Georgia has an important protection for homeowners called the three-year assessment freeze under O.C.G.A. § 48-5-299(c). After a successful appeal, your assessed value is locked for three years. The county can't raise it during that period without cause.
New construction is one of the exceptions that breaks this freeze. If you win an appeal and lock in a value, then add a pool or expand your kitchen, the county can reassess the entire property. The freeze resets.
This is worth understanding before you start a project. If you're two years into a three-year freeze and planning a major renovation, consider whether the timing makes sense. Once the freeze breaks, the assessor can reassess everything, not just the improvement.
There's a flip side, though. If you appeal your new construction assessment and win, the three-year assessment freeze kicks in on the new, lower value. At 30 mills, getting your assessed value reduced by $40,000 saves $1,200 per year, or $3,600 over the three-year freeze period.
Georgia voters approved Amendment 1 in November 2024 with 63% support. The implementing legislation, HB 581, caps how much a homestead property's assessed value can increase due to inflation each year.
There's a major catch: new construction is excluded from this cap. If you build a new home, your property is assessed at full current fair market value with no inflation adjustment. Meanwhile, your neighbor who has owned an identical home for a decade may have an assessed value tens of thousands of dollars lower, thanks to the cap protecting them from years of market appreciation.
This creates a real disparity. A long-time homeowner with a $500,000 home might have an assessed value of only $134,000 (40% of a historically lower FMV), while your brand-new $500,000 home is assessed at $200,000. You're paying significantly more in taxes for the same home on the same street.
Some appeal practitioners are beginning to raise uniformity arguments based on this disparity, though the legal landscape is still developing.
Note that Gwinnett County has opted out of HB 581 entirely, so the cap doesn't apply there regardless.
If your new construction assessment looks inflated, you have every right to challenge it. When the Board of Tax Assessors increases a returned value, the burden of proof is on them to justify the change.
You'll receive a PT-306 (Annual Notice of Assessment) from your county, typically between April and July depending on where you live. Fulton County usually mails notices in April or May, while Gwinnett and DeKalb send theirs in May. Compare the listed fair market value against what you actually paid to build (land + construction) and what similar completed homes are selling for.
Request your property record card from the assessor's office. Look for wrong square footage, incorrect number of bedrooms or bathrooms, inaccurate construction quality ratings, or features you don't have. Errors here are surprisingly common for new construction because the record is being created for the first time.
For new construction appeals, the strongest appeal evidence typically includes:
The uniformity angle is particularly powerful for new construction. If the assessor valued your home at $250 per square foot but comparable new builds in the same subdivision are assessed at $210 per square foot, that discrepancy is hard for the county to explain away.
You have 45 calendar days from the date on your assessment notice to file an appeal using the PT-311A form. File with the Board of Tax Assessors (not the Board of Equalization, not the tax commissioner). Filing with the wrong office doesn't stop the clock.
If you want to file a property tax appeal in Georgia without navigating the process alone, AppealAlly's Do-It-Yourself Appeal Kit ($79) includes a complete evidence packet with comparable sales analysis and step-by-step instructions, backed by a 100% money-back guarantee. For homeowners who'd rather not deal with paperwork at all, the Full-Service Appeal handles everything for 30% of first-year savings with nothing due upfront.
After filing, the Board of Tax Assessors reviews your appeal and may send a counter-offer. You have 30 days to accept or reject it. If you reject, the appeal proceeds to one of three forums:
One concern people have: can your assessment go up if you appeal? Technically, the BOE can set a value higher than what the assessor proposed, though this is rare. The far more common outcome is a reduction.
A Gwinnett County homeowner completed a $120,000 renovation that included a kitchen expansion and master suite remodel. Before the renovation, the home's fair market value was $412,500.
After the project, the county assessor increased the FMV to $585,000. That's the $412,500 original value plus the $120,000 renovation cost, plus an additional $52,500 “market adjustment” with no clear documentation.
The homeowner appealed to the Board of Equalization with three pieces of evidence: the actual contractor invoices totaling $120,000, comparable sales of similar renovated homes showing values around $530,000, and the property record card (which listed an extra half-bathroom that didn't exist).
The BOE reduced the fair market value to $530,000, lowering the assessed value by $22,000. At Gwinnett's ~34 mill rate, that's roughly $748 per year in savings. With the three-year assessment freeze, the total savings exceeded $2,200.
AppealAlly users appealing new construction and renovation assessments see average savings of $497 per year, roughly $1,500 over three years, with an 86% success rate.
Not every improvement adds dollar-for-dollar to your assessment. Here's a realistic range for common projects, assuming a 30-mill blended rate:
The range depends on how aggressively your county values the improvement and whether comparable sales support the full cost being reflected in market value. Renovation costs don't always translate one-to-one into market value. A $50,000 kitchen remodel might only add $35,000 in resale value, and your assessment should reflect the market value, not the construction cost.
If you're buying your first home in Georgia and it's new construction, these numbers are especially important for budgeting. Your mortgage lender estimated property taxes based on something, and it may not match what the county eventually assesses.
Assessment timelines vary across Georgia's 159 counties. Here are the major metro counties:
Fulton County — Notices typically mailed April–May. Appeals accepted online, by mail, or in person. Phone: 404-612-6440.
Gwinnett County — Notices mailed in May. Has opted out of HB 581. Appeals accepted online, by mail, or in person. Phone: 770-822-7200.
DeKalb County — Notices mailed late May. The county was granted an extra 180 days for assessment review in 2025. Phone: 404-371-0841.
Cobb County — Notices mailed around May 23 in 2025 with a July 7 deadline. Phone: 770-528-3100.
Regardless of county, the 45-day appeal window starts from the date printed on your notice, not the date you received it. Mark your calendar the day the notice arrives.
New construction in Georgia, whether it's a brand-new home, a major addition, or a significant renovation, triggers reassessment and is valued primarily using the cost approach. The January 1 assessment date controls timing, building permits alert the assessor automatically, and the temporary billing rules for new construction default to 85% of the current year with no prior-year cushion.
Check your property record card for errors the moment you receive your assessment notice. The cost approach frequently overstates value because standardized cost tables don't reflect your actual construction costs or the market's willingness to pay. You have 45 days from the date on your notice to file a PT-311A appeal with the Board of Tax Assessors.
New construction breaks the 299(c) freeze, but winning an appeal on your new assessment locks in the reduced value for three years. Amendment 1 / HB 581 doesn't protect new construction from full-value assessment, creating potential disparities with neighboring homes. And the burden of proof is on the assessor when they increase a returned value, so bring your contractor invoices, comparable sales, and any independent appraisal to the appeal.
Whether you just completed a build or you're still in the planning phase, understanding these rules puts you in a much stronger position to manage your property tax burden going forward.