Why assessed value and market value drift apart
Mass appraisal is a reasonable way to value a whole county and a poor way to value one house. The model works from public records, recent sales in the area, and broad property characteristics. It does not know:
- What condition your house is in. A renovated kitchen and a 1980s kitchen look identical in county data.
- Whether the recorded square footage is right. County records are wrong often enough that measuring on site regularly changes the answer.
- What is wrong with the property. A failing roof, foundation movement, an unpermitted addition or a functional layout problem are all invisible to the model.
- Which nearby sales were not arm's length. Family transfers and distress sales get absorbed into the averages.
When a neighbourhood is appreciating quickly, the model tends to catch up in steps rather than smoothly, which is why assessments sometimes jump in a way that does not match what the property would actually sell for on January 1.
When an appeal is worth filing, and when it is not
Worth saying plainly, because most pages on this subject will not: an appeal is not always worth the cost.
The saving from a successful appeal is a function of the assessment reduction and your millage rate. If the county's figure is within a few percent of market value, the likely reduction may not cover the appraisal fee, and the honest answer is to leave it alone. An appeal is usually worth pursuing when:
- The assessment rose sharply and nothing about the property changed.
- The property has condition problems the county has no way of knowing about.
- The recorded square footage or bedroom and bathroom count is simply wrong.
- Comparable homes nearby are assessed materially lower without an obvious reason.
- You bought recently, at arm's length, for less than the assessed value.
We will tell you when we think the gap is too small to be worth chasing. An appraisal that confirms the county was right is still a legitimate outcome, and it is better to know that before you have built a case around it.
What the board of equalization is weighing
An appeal is an evidentiary exercise. The board is comparing what the county says the property is worth against what you can show it is worth. Evidence that carries weight:
- An independent appraisal with a stated effective date matching the assessment date.
- Photographs of condition issues, with repair estimates where they exist.
- Verified comparable sales selected on a defensible basis rather than the cheapest sales you could find.
- Corrections to the county's property record, where square footage or features are recorded wrong.
Arguments that carry little weight: that the tax bill is high, that you cannot afford it, that neighbours pay less without a supporting valuation reason, or that an online estimate shows a lower figure.
Counties across Metro Atlanta do not work the same way
Cobb, Fulton, DeKalb, Cherokee, Gwinnett and Forsyth each run their own assessment and appeal process. They differ in how notices are issued, how hearings are scheduled, how quickly they move, and how receptive they are to different kinds of evidence.
Two things are consistent across all of them. First, the assessment date is January 1, so the appraisal must be written to that date. Second, the window to appeal runs from the date on your annual notice of assessment, and it is short.
Check the deadline printed on your own notice. Filing windows change from year to year and county to county, and a deadline repeated from a website is not a deadline you should rely on. If the notice has arrived, the clock is already running, and the appraisal needs to be ordered with enough time to be completed before it closes.
