The Board of Review is not the last word on your assessment. If the Board's decision still leaves your property assessed higher than comparable ones, you can take the case to the Illinois Property Tax Appeal Board — a state agency, independent of Cook County, that hears the case fresh. The window is short: 30 days from the date on the Board's final decision.
What the Property Tax Appeal Board is
The Illinois Property Tax Appeal Board, usually shortened to PTAB, is a state body that reviews local assessment decisions from every county in Illinois. It is not part of the Cook County Assessor's office and not part of the Cook County Board of Review. Its members are appointed by the Governor, and it exists so that an owner who believes a county got the assessment wrong has somewhere outside that county to be heard.
PTAB hears the case de novo — Latin for "anew". It does not ask whether the Board of Review made a reasonable decision on the papers in front of it. It looks at the evidence presented to it and decides what the assessment should be.
When you can use it
Two conditions, and both are strict:
- You must have appealed to the Board of Review first for that tax year. PTAB reviews a Board of Review decision, so if there is no decision there is nothing for it to review. An owner who skipped the county appeal cannot start at the state.
- You must file within 30 days of the Board's final decision. The clock runs from the date on the written decision, not from the day it reaches your mailbox and not from the day you open it. This deadline is jurisdictional: miss it and PTAB cannot hear the case at all, however strong it is.
Because Cook County decides township by township, your 30 days depend on when your township's Board decisions are issued — not on a single county-wide date. Our deadlines page tracks each township's dates as the county publishes them.
What it costs
Filing with PTAB is free. There is no filing fee for a residential appeal, and no fee to be represented. What a PTAB case actually costs an owner is usually evidence: a PTAB case is often won or lost on a professional appraisal, and appraisals are not free.
What PTAB looks at
The same arguments that work at the county work at the state, but the standard of proof is higher and the record is more formal:
- Uniformity — your assessment compared with genuinely comparable properties. This is the backbone of most residential cases.
- Market value — evidence that the property is assessed above what it would sell for. A recent arm's-length sale of the property itself is powerful. An independent appraisal close to the assessment date carries real weight.
- Income — for commercial and multi-unit property, actual rent rolls and operating expenses, analysed the way a buyer would.
Evidence is exchanged on a schedule, and the Board of Review can submit evidence defending its own decision. Assertions without documents do not carry a PTAB case.
How long it takes
Be realistic: PTAB is slow. A residential case commonly takes a year or more, and complex commercial cases can run considerably longer. Meanwhile the tax bill based on the county's assessment still arrives and still has to be paid. If PTAB later reduces the assessment, the county refunds the difference — but the money comes back afterwards, not instead.
That timing is exactly why the county appeal matters so much. A reduction won at the Assessor or the Board of Review shows up in the next bill. A reduction won at PTAB shows up eventually, as a refund.
The risk worth knowing about
PTAB decides what the correct assessment is, and that cuts both ways: it can leave the assessment where it is, lower it, or raise it. That is rare in residential cases with sound comparables, but it is a real feature of the process and it is the reason a PTAB appeal deserves a considered look at the evidence before anything is filed, rather than an automatic filing after every disappointing decision.
PTAB or the Circuit Court?
An owner who has paid the tax bill has a second route: a tax objection complaint in the Circuit Court of Cook County. The two are alternatives, not steps — you choose one path or the other for a given year, and the choice has consequences for timing, cost and what has to be proved. Court cases involve litigation costs that a PTAB appeal does not, and the deadlines are calculated differently. Which route fits is a case-by-case judgement, and it is worth an attorney's view before the 30 days run out.
What we do
We appeal residential and commercial assessments at the Cook County Assessor and the Board of Review as a matter of course, and we look at every unsuccessful Board decision to see whether the evidence would support a state appeal. Where it would, we say so; where the comparables do not support it, we say that too, because filing a weak case costs the owner time and can expose the assessment to an increase.
Our fee is contingent — there is no upfront cost, and no fee at all if the assessment is not reduced. If you have a Board of Review decision in hand and the 30 days are running, speak to a property tax attorney before the window closes, or start with a free review of your parcel.
See our appeal FAQs for how the Cook County process works from the beginning, and the Board of Review guide for the county stage that has to come first.
