Most Cook County homeowners never appeal, and many who do file without a lawyer. Filing is free. Here's the whole process for a single-family home or small multi-unit building you own and live in.
1. Find your township's window
Cook County is reassessed in three parts (the City of Chicago, the north suburbs, the south and west suburbs) on a three-year cycle, and appeal windows open township by township. After the Assessor mails your reassessment notice you have about 30 days to appeal to the Assessor. Later in the year the Board of Review opens your township for its own appeal window. See every township's dates.
2. Check whether your assessment looks high
The most common ground is lack of uniformity: similar homes nearby are assessed at a lower value per square foot than yours. Run the free check to compare your home with the most similar homes in your assessment neighborhood. Other grounds include a recent purchase price below the Assessor's market value, wrong characteristics (square footage, number of units), and damage or vacancy.
3. Gather your evidence
- 3 to 5 comparable homes: same neighborhood and class, similar size and age, with their PINs and assessed values.
- If you bought recently: the closing statement and sale price.
- If the square footage is wrong: a plat of survey, appraisal or floor plan.
- Photos, if condition is part of your case.
4. File with the Assessor
File online at the Assessor's appeals page while your township is open. You'll enter the PIN, choose the reason, and upload your evidence. There's no fee.
5. File with the Board of Review
The Board of Review is a separate office with its own window. You can appeal there whether or not you appealed to the Assessor, and whether or not the Assessor gave you a reduction. Filing is free and online. Only the owner or an Illinois attorney may file for a home, and property owned by an LLC or trust needs an attorney.
6. After you file
Each office reviews the evidence and posts a decision, often months later. A reduction shows up on a later tax bill. If the Board denies your appeal, you can appeal to the Illinois Property Tax Appeal Board within 30 days of the Board's decision.
Don't skip exemptions
The homeowner and senior exemptions can be worth more than an appeal, and missed ones can often be claimed for past years. Run the exemption check.
General information, not legal advice. Dates and rules come from the Assessor and the Board of Review; check their sites before you file.