If a property assessment notice just landed in your Fulton, Cobb, Gwinnett, or DeKalb mailbox, the most important number on the page is not the value the county put on your home. It is the date printed at the top. Under Georgia law, your clock to appeal started ticking on that Notice Date — the mailing or print date — not the day you actually opened the envelope. You have 45 days, and missing them forfeits your appeal for the entire tax year.
Metro Atlanta values have stayed elevated even as the broader market has softened, so a fresh notice can read higher than what you think your house would fetch today. That gap is exactly what the appeal process exists to test. This guide walks through how Georgia's assessment math works, the firm 45-day rule, the evidence that actually moves value, the three-year freeze and the 2025 change that reshaped it, and how a lower assessment eventually reaches your monthly mortgage payment.
How Georgia assessment math works
Georgia does not tax your home on its full fair market value. By law, property is assessed at 40% of fair market value unless a statute says otherwise (Georgia Department of Revenue). That 40% figure is your assessed value, and it is what the tax is calculated against. The basic formula is:
Fair market value × 40% × millage rate, less any exemptions = your tax.
Two consequences follow. First, because only 40% of the value is taxed, a change in fair market value translates into a smaller change in assessed value — but it still flows straight through to the bill. Second, the value on your notice reflects the property as of the January 1 valuation date. An appeal is an argument about what your home was worth on that date, which is why the comparable sales and condition evidence you gather should cluster around it rather than reflect today's listings months later.
The 45-day rule, in detail
Georgia's appeal window comes from O.C.G.A. 48-5-311, which gives owners 45 days from the assessment notice's Notice Date to file a written appeal with the county Board of Tax Assessors (Georgia Department of Revenue). The clock runs from the mailing/print date shown on the notice — not from when it reached you, and not from when you read it.
Timing of your filing is judged generously, but only in specific ways. A notice of appeal is deemed filed as of the USPS postmark date, a statutory overnight delivery receipt, or — only if your county has formally adopted a written e-service policy — the email transmission date (O.C.G.A. 48-5-311 summary, Georgia House of Representatives). If the 45 days pass with nothing filed, the appeal for that tax year is gone. There is no general extension for a late notice or a busy month.
Filing the appeal
You can appeal using the state's uniform PT-311A form or a written letter to the Board of Tax Assessors. Georgia recognizes four grounds: value (the most common — you believe the fair market value is too high), uniformity (your assessment is out of line with comparable properties), taxability, or denial of an exemption (Georgia Department of Revenue).
At filing, you must also elect one of three triers of fact — the body that decides your appeal if the assessor doesn't resolve it first (Georgia Department of Revenue):
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County Board of Equalization (BOE): no cost to the owner and the most common choice. A panel of citizens hears value, uniformity, taxability, and exemption appeals.
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Hearing officer: generally used for non-homestead real property and wireless property, and typically for higher-value parcels.
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Arbitration (binding or nonbinding): requires you to obtain a certified appraisal, which adds cost but puts a professional valuation on the table.
The process usually has a built-in off-ramp before any hearing. The assessor reviews your appeal first and may change the value, sending what's often called a 30-day letter. If you accept the revised value, you're done; if you don't respond or reject it, the appeal is certified to the trier of fact you chose.
One caution worth stating plainly: the trier of fact can move your value up, down, or leave it unchanged. There is genuine downside risk to filing an appeal you can't support with evidence. This is not a no-lose lottery ticket.
The three-year freeze — and the HB 581 change
The prize many owners are after is the three-year freeze under O.C.G.A. 48-5-299(c). When it applies, it locks your assessed value for the appeal year plus the next two tax years. During that window, county-wide reassessments and ordinary market appreciation cannot push the frozen value higher (Ownwell).
Here is the critical update, and it changes the whole calculus: HB 581, the Save the Homes Act — approved by voters in November 2024 and effective for the 2025 tax season — eliminated the old automatic freeze that used to apply simply because you filed an appeal (Appen Media). Under current law, the appeal must succeed with an actual value reduction — through the BOE, a hearing officer, an arbitrator, a settlement, or Superior Court — to earn the 299(c) freeze (Ownwell).
So set expectations honestly. Filing alone no longer buys you anything but a hearing. To lock the freeze, you have to win a lower number, and that decision needs to carry the 299(c) language. An informal, assessor-only adjustment may not trigger the freeze — the 299(c) protection should appear in the written decision or settlement, not just show up as a quietly revised value.
What breaks the freeze
Even once you have a 299(c) freeze, several events end it early (Ownwell):
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Sale or transfer of the property.
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Substantial improvements or new construction that add value.
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Filing a new appeal on the property.
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Filing a property tax return at a different value.
The first two are the common surprises: a renovation that adds square footage or a sale resets the clock, so a freeze is best thought of as protection for a home you plan to keep as-is for a few years.
The evidence that wins
Because you now need an actual reduction, the quality of your evidence is everything. The strongest material for a value appeal (Ownwell) includes:
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Recent comparable sales — closed sales of similar nearby homes, dated near the January 1 valuation date rather than current asking prices.
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A fee appraisal — a professional valuation, which is also required if you choose arbitration.
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A listing or sale of your own home below the assessed fair market value — direct evidence about the subject property itself.
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Documented condition issues — photos and repair estimates for foundation, roof, or system defects that the assessor's mass appraisal wouldn't have captured.
Remember the two-way risk: if your evidence is thin and the comps actually point higher, the trier of fact can raise your value. Build the case before you commit to a hearing.
Metro Atlanta specifics
Counties mail notices on their own schedules between roughly April and June, and the deadline printed on each notice is what governs. The 2025 cycle illustrates how much they vary:
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Fulton County made 2025 notices available with an appeal deadline of August 1, 2025 (Fulton County, GA).
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DeKalb County mailed notices in May/early June for 2025 (DeKalb County Tax Commissioner).
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Gwinnett County uses 45 days from the date printed on the notice for its 2025 window (Gwinnett County).
Cobb follows the same statewide 45-day framework. The practical rule for every metro county is identical: defer to the Notice Date and deadline printed on your own notice, and don't assume your county matches a neighbor's calendar.
One more HB 581 wrinkle: the floating homestead exemption
HB 581 did more than change the freeze. It also created a separate statewide floating homestead exemption that caps annual growth in a homestead's taxable assessed value to inflation, measured by CPI (Newton County, GA). This is distinct from — and not a substitute for — the 299(c) appeal freeze. The two can coexist, and the floating exemption isn't universal: the City of Atlanta and some taxing districts opted out. If you're counting on either protection, confirm which ones apply where your property sits.
From assessment to your monthly payment
For most homeowners with a mortgage, this is the part that matters. A lower assessed value lowers the annual property tax bill. If your taxes are escrowed, your servicer recalculates the escrow account at its next annual escrow analysis — which can lower your monthly payment, generate an escrow surplus refund, or both.
The important caveat is timing. The relief lags the appeal by a tax and escrow cycle: you win a reduction, the county adjusts the tax bill, and only at the next analysis does the servicer reset your monthly payment. Don't expect the win to change your statement the following month — but over the cycle, a meaningful reduction is real money back in your budget.
Action checklist
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Read the Notice Date on your assessment notice — that's when the clock started.
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Calendar the 45-day deadline (or the explicit deadline your county printed) and work backward.
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Gather evidence: closed comps near January 1, a fee appraisal if warranted, and photos plus repair estimates for any condition issues.
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Decide your grounds (value, uniformity, taxability, or exemption) and elect a trier of fact — BOE for no cost, hearing officer for higher-value/non-homestead, or arbitration if you have a certified appraisal.
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File before the clock runs, using PT-311A or a written letter, by mail (mind the postmark), statutory overnight, or e-service if your county allows it.
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Insist on 299(c) language in any reduction you accept, so a genuine win locks the three-year freeze rather than evaporating next cycle.
The single discipline that decides most appeals isn't legal cleverness — it's the calendar. Find the Notice Date, count 45 days, and start building your evidence today.
Related reading
Sources
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PT-311A Appeal of Assessment Form — Georgia Department of Revenue
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Summary of Appeal Process, O.C.G.A. 48-5-311 — Georgia House of Representatives
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Appealing tax assessment won't freeze values starting next year — Appen Media
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Fulton County 2025 Assessment Notices Are Now Available Online — Fulton County, GA
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Deadline to Appeal Notice of Assessment — DeKalb County Tax Commissioner
