A property tax assessment appeal asks the county to lower the value it put on your property, and so your tax. In Cook County you usually appeal to the Assessor, then the Board of Review, each in your township's filing window, then to the state Property Tax Appeal Board (PTAB) or the Circuit Court. Filing at the Assessor, the Board of Review and PTAB is free.
What an appeal changes, and what it does not
An appeal is about your property's assessed value, the figure your tax bill is calculated from. You do not appeal the bill itself, and the tax rate is not part of it. Homes and apartment buildings are assessed at 10% of market value, and most commercial property at 25%. The tax rates, and the amounts your school district, village and the county ask for, are set elsewhere, so an appeal cannot change them. A lower assessment usually lowers your bill, because your share of the total falls. If your assessment is reduced, the lower tax shows on your second-installment bill the following year.
The grounds: similar properties, market value, record errors
You have a case if any of these is true: similar properties nearby are assessed lower; the Assessor's market value is higher than the property would sell for; or the county's record of it is wrong, for example its size.
- Similar properties assessed lower. Compare homes in the same neighborhood and the same class code, as close to yours in age and style as you can find. Divide each home's building assessment by its building square footage; if yours is higher per square foot, that gap is your case.
- Market value. If you bought the property in the past three years, in an arm's-length sale, for less than the Assessor's market value, your closing documents are your evidence. Recent sales of similar homes, or an appraisal, can show the same.
- Record errors. If the county lists the wrong size, age or features, correcting the record can lower the assessment on its own.
Where an appeal is filed
You can challenge a Cook County assessment at up to three levels, in this order: the Cook County Assessor, the Board of Review, and then the Illinois Property Tax Appeal Board (PTAB) or the Circuit Court. The Assessor is optional, but filing there gives you two chances at a reduction instead of one.
- The Assessor decides after your township's window closes, usually within a few weeks to a few months.
- The Board of Review decides later the same assessment year, before second-installment bills are issued.
- After the Board of Review decides, you can go to PTAB or to the Circuit Court, not both. PTAB cases often take two years or more.
Each township's filing dates are on our deadlines page.
How often you can appeal
You can appeal every year, not only in your reassessment year. For a home, a reduction usually stays in place for the rest of your township's three-year reassessment cycle. The county can change it in a later year, so we review your assessment each year.
What it costs
Filing at the Assessor, the Board of Review and PTAB is free. If you choose the Circuit Court, you pay the court's filing fee; we tell you the amount before we file. If we file for you, our fee is 25% of first-year savings, only if your assessment is reduced.
Homes and commercial property
Homes are usually appealed on similar homes nearby or a recent purchase. A commercial assessment is an income calculation. The Assessor values most commercial buildings from the rent they earn and what they cost to run. So the case is built from the building's own records. If an LLC, corporation or other company owns the property, the Board of Review and PTAB require a licensed attorney to represent it.
How to start
The full guide: How do I appeal my Cook County property taxes? →
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