Two offices, one path
Two county offices handle a Cook County appeal: the Assessor's Office sets your home's value, and the Board of Review hears appeals of it. Each of the county's 38 townships opens on its own schedule, first at the Assessor, then at the Board.1, 4
- Cook County Assessor's Office
Estimates your home's market value and reassesses each region every three years. You can appeal during your township's window, typically 30 days after your reassessment notice.2, 3
- Cook County Board of Review
A separate, quasi-judicial agency, independent of the Assessor. Its decision sets the final county value on your property for that tax year.4
- Property Tax Appeal Board or Circuit Court
Optional next steps, after the Board of Review.4
When your township opens
Cook County reassesses property every three years, one region at a time.2
| Region | Reassessed in |
|---|---|
| City of Chicago | 2024 and 2027 |
| North suburbs | 2022 and 2025 |
| South and west suburbs This year | 2023 and 2026 |
In 2026, it's the south and west suburbs' turn. Homes in the City of Chicago and the north suburbs aren't being reassessed this year, but their owners can still appeal when their township opens.1
Open at the Assessor's Office
| Township | Area | Last day |
|---|---|---|
| Leyden | North suburbs | Oct 14 |
| Worth | South and west | Oct 15 |
| Wheeling | North suburbs | Oct 22 |
| Proviso | South and west | Oct 27 |
| Lake | Chicago | Oct 29 |
| Palatine | North suburbs | Nov 4 |
| Orland | South and west | Nov 6 |
| Jefferson | Chicago | Nov 12 |
| Schaumburg | North suburbs | Nov 19 |
| Thornton | South and west | Nov 23 |
| North Chicago | Chicago | Nov 24 |
Not yet open on that calendar: Rich and Bloom in the south suburbs, and Niles, Hanover and South Chicago. The rest have closed for 2026 at the Assessor.1
Open at the Board of Review
Lyons, Northfield, Stickney and West Chicago, through November 6, 2026. Evidence is due by November 16.5 This window has now closed.
See your free savings estimateWhat an appeal can question
The Assessor's guide to residential appeals names three grounds.3
- The value
- Overvaluation: the estimated market value is more than your home is worth. Recent closing statements, or the purchase prices of similar homes, can support it.3
- Uniformity
- Your assessment is out of line with comparable homes in your assessment neighborhood, similar in characteristics such as class, age, building size, land size and construction.3
- The facts
- Incorrect information about your home, such as the wrong square footage.3
You don't have to submit comparable properties. The Assessor's analysts review similar homes themselves.3
Market value and assessed value. Estimated market value is what the Assessor believes homes like yours are worth in the current market. For residential property, the assessed value used to calculate your taxes is usually 10 percent of it.3
The Assessor offers its own test for whether an appeal is worth filing:
“If the property characteristics on this notice are correct and the estimated market value is within 10 percent of what you think your home is worth then it is unlikely that an appeal would change your property's assessed value enough to significantly affect its property tax bill.”
If an appeal is granted and nothing about the property changes, that value stays your assessed value until the next reassessment.3
Before you file
Start with your own number. Get a free savings estimate. No commitment.
See your free savings estimateAt the Board of Review
The Board of Review opens each township after the Assessor has finished it, for at least 30 days. Its dates vary every year and aren't set in advance. Once a township closes, appeals wait until the next year.4
“You are at no disadvantage if the Assessor has granted or denied a request to reduce the assessment.”
- Filing
- Online, in person, or at an outreach seminar held in the community. Filing at the Board of Review is free.4
- A lawyer
- Not required for a home held in your own name, though you may hire one if you choose. Property held by a corporation or LLC must be represented by an attorney.4
- Evidence
- A photo of the property you're appealing is required. Evidence can be submitted up to 5 days before your hearing.4
- The hearing
- Hearings for homeowners representing themselves are held by phone. If you have nothing to add, you can waive the hearing; the Board says it won't penalize you for that, and its analysts review files the same way either way.4
- The year
- The Board can only hear the current year, not a prior one.4
Up or down. The Board of Review can confirm, raise or lower an assessment. Before changing one on its own motion, it must notify you and give you a chance to be heard.6
If you still disagree
After the Board of Review, you can appeal further to the Illinois Property Tax Appeal Board (PTAB) or to the Cook County Circuit Court.4 PTAB is a state board whose five members are appointed by the Governor. It decides the correct assessment, not the size of your bill or the tax rate.7
In Cook County, a PTAB appeal is due within 30 days of the Board of Review's notice, or of the date the Board sends its final action on your township to the Assessor, whichever is later.7
Your tax bill while you wait
An increase or decrease in your assessment doesn't lead to the same change in your taxes. Your bill also depends on exemptions, the total assessed value of your community and the levies passed by local taxing bodies.3
- First installment
By law, 55 percent of last year's total bill, with a March 1 due date.4
- Second installment
Not issued until the Board of Review has finished every appeal in all 38 townships.4
- When a change shows
Bill changes from a reassessment show up on the second installment bill the year after.3
So don't hold your payment for a decision.4
