When not to appeal your property taxes
Most advice tells you to always appeal. The county's own data says otherwise. Six situations where filing is a waste of an evening, and what to do instead.
Nearly every article on this subject reaches the same conclusion: appeal, because it is free and you might win. That advice made more sense in 2021, when 31.9% of decided Cook County appeals produced a reduction. In 2025 the figure was 16.2%.
Filing is still close to costless in money. It is not costless in time, and time spent on a hopeless filing is time not spent on the exemption that would have been worth more. Here is when the arithmetic says don't.
1. When you have not claimed your exemptions
This is first because it is the most common and the most expensive mistake.
A Cook County homestead exemption is worth more than the median successful appeal, is granted on an application rather than won on an argument, and takes a fraction of the time. Senior, senior freeze, veterans' and disability exemptions stack on top.
Appealing while an exemption sits unclaimed is optimising the smaller number at longer odds. Check the exemption lines on your bill before anything else.
2. When your assessment is close to your neighbours'
The core of a uniformity appeal is that similar properties are assessed lower. If your assessment per square foot sits within roughly 10% of comparable properties nearby, there is no argument to make — that is inside normal valuation tolerance and no board will move it.
In our comparison across two states, about 92% of properties fall in this category. Checking takes minutes; filing without checking takes an evening and, statistically, achieves nothing.
3. When your comparables are not comparable
A common failure is assembling five lower-assessed properties that differ from yours in ways that justify the difference — a different neighbourhood code, a different building class, materially different size or age.
4. When you just bought at or above the implied value
Your purchase price is the strongest single piece of evidence about what your property is worth, and it works in both directions. If you paid $420,000 and the county's implied value is $390,000, that document is the opposite of your case.
At the Cook County Assessor stage an assessment cannot be raised, so the downside is limited. At the Board of Review it can be — and when residential assessments are raised on appeal, an above-implied purchase price supplied by the appellant is the most common reason.
5. When you are late in the reassessment cycle
A reduction generally holds until the next reassessment: three years in Cook County, four in most other Illinois counties, five in Connecticut.
| When you win | Years of benefit | Value of an $574/yr reduction |
|---|---|---|
| Year 1 of the cycle | 3 | $1,721 |
| Year 2 | 2 | $1,147 |
| Year 3 | 1 | $574 |
The same work is worth three times as much at the start of a cycle. A marginal case in year three is usually better saved for the fresh assessment coming next year, when the same evidence has three years to run.
6. When the gap is so large it is a record error
If your property appears assessed 400% above its neighbours, you do not have an extraordinary appeal. You have a mistake in the county's file — a commercial classification on a house, a whole building's assessment on one condo unit, a transposed digit in the square footage.
Taking that to a uniformity hearing is the wrong forum. Call the assessor's office and ask about a record correction: faster, more likely to succeed, and unlike an appeal it does not expire at the next reassessment.
The one case where you should file regardless
If the county's facts about your property are wrong — the square footage, the bedroom count, the year built, the classification — pursue it whatever the odds look like. That is not a matter of judgement and the correction is permanent.
The honest position
Appeals are worth filing when the arithmetic supports them, which is roughly one property in twelve. The rest of the time the better move is to claim every exemption you are entitled to, check the record card for errors, and put the evening back.
"Always appeal, it's free" is advice that costs you nothing to give and an evening to follow.