Most Marion County homeowners treat their assessment notice as a verdict. It is not — it is an opening number, and the county's own results prove it. A WRTV Investigates review of appeal data found that in 2024, Marion County homeowners filed 7,744 assessment appeals and 3,097 of them succeeded — a 40% success rate. Across the Central Indiana counties WRTV surveyed (Boone, Delaware, Hamilton, Hancock, Hendricks, Johnson, and Marion), the average was even higher: 48% of appeals ended in a reduction for the homeowner.
Here is the part that should get your attention: despite those odds, only about 2-3% of Marion County homeowners ever file.
What the Numbers Actually Say
The 2024 figures are worth sitting with, because they cut against the two most common assumptions homeowners make.
| Assumption | What the 2024 data shows |
|---|---|
| "Appeals never work" | 40% of Marion County appeals succeeded; 48% on average across surveyed Central Indiana counties |
| "The assessor fights every appeal" | Many appeals resolve at an informal review with assessor staff, before any hearing |
| "Everyone who is over-assessed appeals" | Only 2-3% of Marion County homeowners file at all |
Marion County Assessor Joseph O'Connor — who has held the office since winning re-election in 2022 and told WRTV his office does not view appeals as a bad thing — put it plainly: "We want to fix that mistake or make that property assessed at what it's truly worth."
O'Connor also explained the mechanism that makes so many assessments contestable: "We use the 12 months of preceding sales, so really this bill in your hand is representing a 2024 real estate market." Your assessment is a mass-appraisal estimate built from the prior year's sales across your area. It is not an appraisal of your house. When the market model and your specific property diverge, that gap is exactly what an appeal corrects.
He noted the scale of recent movement, too: the median assessed value in Marion County increased over 25% across the four years preceding the WRTV report. Mass appraisal moving that fast produces individual errors — in both directions.
A "Should You Appeal?" Decision Framework
A 40% base rate is the average across everyone who filed — well-prepared appeals and hopeless ones alike. Your personal odds depend almost entirely on which category you are in.
When the odds favor you
- Comparable sales sit clearly below your assessed value. This is the strongest position in Indiana. If recent arm's-length sales of genuinely similar homes in your area cluster below your AV, you have the kind of evidence boards act on. Our guide to comparable sales evidence for PTABOA appeals walks through building that package.
- Your property record card has errors. Wrong square footage, a finished basement you don't have, a phantom bathroom, an incorrect construction grade. These are objective, checkable facts — and the easiest wins, because there is nothing to argue about.
- You own income-producing property with documented income. For rentals and commercial parcels, actual rent rolls and operating expenses can support an income-approach value below the assessor's model. Documentation is the whole game here.
- Condition problems the model can't see. Foundation issues, an aging roof, functional obsolescence — mass appraisal assumes typical condition. Photos and repair estimates make the invisible visible.
When the odds don't favor you
- Comps support the assessment. If similar homes nearby are selling at or above your AV, you are asking the board to ignore the market. That appeal loses.
- Your only argument is the tax bill. "My taxes went up too much" is not evidence of an incorrect value. The board reviews the assessment, not your budget.
- You're comparing against list prices or Zestimates. Boards weigh closed, arm's-length sales. Asking prices and algorithmic estimates carry little weight.
Tip
Quick screen before you invest any time: pull three to five recent sales of homes like yours. If most sit below your assessed value, keep going. If they straddle or exceed it, your energy is better spent verifying the record card for objective errors.
What a Win Is Actually Worth
The WRTV report did not publish average dollar savings, so treat the following as straightforward arithmetic rather than a statistic. Your annual savings are roughly your assessed-value reduction multiplied by your effective tax rate:
| AV reduction | At 1.0% effective rate | At 1.5% | At 2.0% |
|---|---|---|---|
| $10,000 | $100/yr | $150/yr | $200/yr |
| $25,000 | $250/yr | $375/yr | $500/yr |
| $50,000 | $500/yr | $750/yr | $1,000/yr |
Two things amplify these numbers. First, a corrected assessment carries forward — the assessor's new value becomes the baseline that future trending builds on, so a win compounds across years. Second, the cost of filing is essentially your time: the Form 130 is free, and many appeals resolve at the informal review stage without a hearing. That asymmetry — meaningful recurring savings against a modest one-time effort — is why the 2-3% participation rate is so striking.
Why do so few people file? The honest answers are inertia, unfamiliarity with the process, and the assumption that fighting city hall is futile. The 2024 data says otherwise: four in ten Marion County filers walked away with a lower value.
The June 15 Deadline Has Passed — Here's What You Can Still Do
For most Marion County homeowners, the Form 130 deadline for the current assessment was June 15, 2026, and it has now passed. That closes the standard appeal window for this cycle, but it does not close every door:
- Objective errors have a longer window. Under IC 6-1.1-15-1.1, certain objective errors — a clerical, mathematical, or typographical mistake; an incorrect property description; an assessment against the wrong person; or a wrongly applied deduction, credit, exemption, or tax cap — can be appealed up to three years after the taxes were first due. If your record card overstates your square footage, you do not have to wait.
- Audit your record card now. Pull your property record card and verify square footage, grade, year built, features, and land value while there is no deadline pressure. Errors you document today become the core of next year's filing — or an objective-error appeal you can file immediately.
- Be ready for the next Form 11. When your 2027-cycle assessment notice arrives, you want your comps and documentation already assembled, not a scramble in the final week before June 15, 2027.
If you did file before this year's deadline, see what happens after you file a Form 130 in Marion County, and start preparing your evidence with our PTABOA hearing evidence guide. For the full procedure end to end, the Indiana property tax appeal guide covers every step.
Note
Marion County appeals can be filed online, in person, or by mail. The online route typically triggers an informal meeting with assessor staff who review the property record with you — many disputes end there, without a PTABOA hearing.
Run Your Own Odds Before Next Cycle
The single best predictor of appeal success is the quality of your comparable sales — and that is exactly what AribaTax is built for. Our property lookup tool puts your assessed value, record-card details, and nearby comparable sales side by side, so you can run the "should I appeal?" screen in minutes instead of guessing. Browse parcel-level data for Marion County to see how your assessment stacks up against your neighbors.
If the comps say you are over-assessed, our tax appeal service assembles the evidence package and files on your behalf when the next window opens. The 2024 numbers say 40% of filers win. The prepared ones win more often than that.