Property tax appeals in Cook County take longer than most owners expect — and that’s not a bad thing. A thorough appeal requires comparable-property research, assessment data, and strategic timing around the county’s filing calendar. Here’s what to plan for.
The short answer
From the day you file your Assessor-level appeal to the day you receive your final decision, expect 3 to 6 months — sometimes longer. If the case continues to the Cook County Board of Review, add another 2 to 4 months. If it continues to the Illinois Property Tax Appeal Board (PTAB), the timeline stretches into multiple years.
Understanding the three-level system
Cook County uses a three-tier appeal process, and the length of your appeal depends on how far you take it.
Level 1 — Cook County Assessor’s Office
This is the first and most common appeal level. The Assessor’s Office accepts appeals during a township-specific filing window that lasts roughly 30 days. You must file your appeal, including comparable property evidence, before that window closes.
From filing to decision, the Assessor typically issues results in 2 to 4 months. Some townships move faster, others slower. The timing depends on the Assessor’s internal caseload and your specific township’s schedule.
Most residential appeals are resolved at this level. If you get the reduction you need, you’re done. If not, you move to level two.
Level 2 — Cook County Board of Review
If you disagree with the Assessor’s decision, you file a second appeal with the Board of Review — a separate three-commissioner panel. The Board’s filing window opens after the Assessor closes that township, typically giving owners a 30-day window to file.
The Board reviews evidence, holds hearings if requested, and issues its own decision. Expect 3 to 5 months from filing to Board decision.
By the time both the Assessor appeal and the Board appeal are complete, you’re looking at 6 to 9 months total — and this represents the majority of successful appeals.
Level 3 — Illinois Property Tax Appeal Board (PTAB)
If you’re still unsatisfied, you can appeal to the state-level PTAB within 30 days of the Board of Review’s final decision. This is where timelines stretch considerably — PTAB cases routinely take 12 to 36 months to resolve.
PTAB is also more formal. Commercial cases typically require legal representation and appraisal evidence. For most residential owners, the cost-benefit doesn’t favor PTAB unless the potential reduction is substantial.
Why the timeline matters
Cook County property tax bills don’t wait for your appeal. If you file an appeal and the township’s second-installment bill comes due before your appeal is decided, you must pay the higher amount. If your appeal later succeeds, you receive a refund — but the refund process itself takes additional time.
This is why timing matters. Filing early in your township’s window gives the Assessor and Board the maximum time to decide before bills come due, reducing the cash flow burden.
What speeds things up (and what slows them down)
Several factors affect how quickly your specific appeal moves:
Faster cases tend to have:
- Clear, well-organized comparable property evidence
- Accurate assessment data from the county’s own records
- Straightforward residential property types
- Filings made early in the township’s window
Slower cases tend to involve:
- Commercial or mixed-use property
- Condo association-level appeals (which must be coordinated across units)
- Complex assessment disputes requiring appraisal
- Cases that continue to the Board of Review or PTAB
Planning your appeal timeline
The best approach: start thinking about your appeal before your township opens. Review your current assessment, identify comparable properties, and prepare your evidence in advance. When the filing window opens, you’re ready to file on day one.
At Gertner & Gertner, we track every Cook County township’s opening dates and prepare cases in advance for our clients. If you’d like us to review your assessment and give you a realistic timeline for your specific property, request a free consultation — we’ll tell you honestly whether an appeal is worth filing and how long it’s likely to take.
This article is for informational purposes only and is not legal advice. For guidance on your specific property, contact Gertner & Gertner, Ltd. at (312) 782-9222.
