Most Cook County homeowners treat a property-tax appeal as one decision: file once, get an answer, done.
It is actually two separate offices, two separate deadlines, and often two separate arguments.
Quick Answer
In Cook County you can appeal first to the Cook County Assessor (CCAO) and then again to the Cook County Board of Review (BOR). They are different government offices with different windows. A reduction at the Assessor does not use up your chance at the Board. The Board reviews the value the Assessor certified, so it can lower it a second time.
That is why a single tax year can hold two opportunities, not one.
Two offices, in order
The Cook County Assessor sets and mails your assessment, then runs the first appeal. Whatever value the Assessor certifies is the starting point for the Cook County Board of Review, which runs its own appeal afterward on its own calendar.
You do not pick one office. For most homeowners the path is: appeal the Assessor in your township's window, then appeal the Board of Review when its window for your township opens.
The numbers behind the second bite
We reviewed Cook County's own assessment records for the 2024 tax year. Across roughly 1.59 million residential parcels:
- About 86,000 homes had a lower value certified by the Assessor than the value first mailed.
- About 194,000 homes had their value lowered at the Board of Review.
- About 19,000 homes saw a reduction at both stages in the same year.
- About 175,000 homes got a Board of Review reduction even though the Assessor had left their value unchanged.
Read that last line again. The single largest group is homes that did not get relief from the Assessor and still got it from the Board. The second office is a real second chance, not a formality.
Two different arguments
The two offices both accept two kinds of evidence, and you do not have to use the same one twice.
- A uniformity argument says your home is assessed higher than similar homes nearby. It is about fairness across comparable properties.
- A market-value argument says the assessment is higher than what the home is actually worth, using sales and property facts.
You can lead with the stronger argument at one stage and the other argument at the next. A home that looks evenly assessed against its neighbors might still be above market value, and the opposite is also common.
Most homes have more than one case
When we scored a sample of 2,000 Cook County homes with our model, about three out of four had both a uniformity case and a market-value case worth researching, not just one.
That is the practical reason the two-office structure matters. Many homeowners stop after one argument or one office and never test the second path that was sitting right there.
What this does not mean
This is not a promise of a reduction. These are historical county counts, and every property is different. Some homes are assessed correctly and should not appeal at all.
It also does not mean you need a lawyer. For Board of Review residential cases, a homeowner can self-submit. Censum's role is to help you see the evidence and prepare the packet, not to file on your behalf in a representation lane.
A simple way to think about it
- Find your township's Assessor window and Board of Review window. Deadlines change, so confirm them on the official calendar before relying on any date.
- Check whether your home has a uniformity case, a market-value case, or both.
- Treat the Board of Review as a separate opportunity, not a tie-breaker.
Sources
- Cook County Assessor, residential appeals and the assessment calendar and deadlines.
- Cook County Board of Review, residential appeals and how to present a case based on lack of uniformity.
- Stage counts are Censum's analysis of Cook County assessment records for the 2024 tax year (residential parcels), comparing the mailed, Assessor-certified, and Board values.
Next step
One appeal is the common mistake. Two offices is the actual system.
Censum helps homeowners see whether a property has a uniformity case, a market-value case, or both, before they file, hire help, or give up a percentage of the result. Censum is independent and is not affiliated with Cook County or any government agency.