Illinois Property Tax Assessment Appeal

In Illinois, you typically must file your appeal within 30 days of the assessment notice. Miss this window and you generally lose your appeal rights for the year — you'll have to wait until the next assessment cycle.

The appeal is filed with the Board of Review (Cook County) or County Board of Review. The exact filing procedure varies by county within Illinois, but most allow online or mail-in filing with a small fee or no fee.

Three situations almost always justify an appeal: (1) your assessed value is meaningfully higher than recent comparable sales in your neighborhood; (2) your home has condition issues (deferred maintenance, structural problems, environmental issues) the assessor didn't account for; or (3) there's a factual error in the assessment record (wrong square footage, wrong number of bedrooms, wrong lot size).

Even a modest reduction — say, 5–10% — can save hundreds or thousands of dollars per year and compound over the time you own the property. Counter Gameplan organizes all of this into a clean, professional letter for you.

The strongest evidence for a property tax appeal is comparable sales (comps) — three to five recent sales of similar properties in your neighborhood, with sale prices below your assessed value. Pull these from public records, your county assessor's online portal, or a local real estate agent.

Independent appraisals carry weight but cost $400–$600. Photographs documenting condition issues, contractor estimates for needed repairs, and any discrepancies between your home and the assessment record (square footage errors, etc.) all strengthen your case.

The Board of Review (Cook County) or County Board of Review typically holds either a paper review or an informal hearing. Informal hearings last 10–20 minutes. You present your evidence, the assessor's office presents theirs, and the board (often 3 members) decides.

Many Illinois counties settle a substantial percentage of appeals before the hearing — once the assessor sees credible comps, they often reduce the value to avoid the hearing entirely.

A successful appeal reduces your assessed value for the current year (and sometimes future years, depending on local rules). Your tax bill is recalculated accordingly. In some Illinois counties, a successful appeal also caps the rate of future increases.

If the appeal board rules against you, most Illinois jurisdictions allow you to appeal further to a state board or court. The timeline for that appeal is short — usually 30–60 days after the initial decision — so don't wait.