Property Tax Appeal:
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Cook County Property Tax Appeals 2025: Deadlines, Evidence & How to File

By Harsha N Hegde

Property taxes feel high because assessments feel high. You can’t appeal your tax bill directly—but you can appeal the assessed value that drives it.
In Cook County, homeowners get two chances to appeal each year—first with the Assessor’s Office (CCAO), then with the Board of Review (BOR).
This guide covers both appeal steps, 2025 township deadlines, evidence that actually works, and what to do if you miss a window.

Quick answer

Who assesses your property and when

Cook County reassesses properties on a three-year cycle across three regions: North/Northwest suburbs, South/Southwest suburbs, and the City of Chicago.
In 2025, the North suburbs are being reassessed. Even if your township isn’t, you can still appeal annually when its appeal window opens.

2025 deadlines: how to find your exact last day to file

Appeal windows open and close by township. Your assessment notice shows the last file date, and both the Assessor and BOR publish calendars.

Example (as of November 2025)

  • Schaumburg Township: open for Assessor appeals until November 17
  • Niles Township: open for Assessor appeals until December 5

Typical timing is about 30 days from the open date.
If you miss the Assessor window, you can still appeal later at the BOR. Both calendars are here:

Two appeal tracks (pick one or run both)

  1. CCAO → BOR → PTAB

    • File first with the CCAO. If the result is unsatisfactory, file again at the BOR when that window opens.
    • If still unsatisfied, file at PTAB within 30 days of the BOR written decision.

  2. Direct to BOR

    • You may skip the Assessor and file directly with the BOR for that tax year’s window.
    • If the BOR result is weak, you can still appeal to PTAB.

What evidence actually helps

Bring facts, not feelings.

  • Recent sales comps for similar homes (size, style, location, condition)
  • Unequal assessment (equity) comps showing your assessed value per square foot is higher than similar nearby properties
  • Property record errors (bed/bath count, finished area, condition, or class) with proof such as photos, permits, or appraisals

Missed a window or found a factual error later? Ask about a Certificate of Error (CoE) to fix prior-year assessed values or missed exemptions.

Step-by-step: filing your appeal

  1. Check your township window (Assessor and BOR). Mark the last file date.
  2. Pull evidence (sales + equity comps, and fix any property-record errors).
  3. File online with the CCAO during its window—or pre-file with BOR when it opens.
  4. Monitor decisions:
    • If CCAO result is weak, file at BOR.
    • If BOR result is weak, file at PTAB within 30 days.
  5. Confirm your savings: ensure the reduction reflects on your next tax bill.

FAQs

How long do I have to appeal?

About 30 days from your reassessment notice (CCAO); BOR windows are separate by township. Always verify the last file date on both official calendars.

Can I appeal my Cook County property taxes every year?

Yes. Even if your township isn’t being reassessed, you can still appeal each year when your township window opens. Annual appeals help correct data errors and keep your assessment fair.

What happens after I file my appeal?

The Assessor or Board of Review reviews your evidence and issues a written decision. If your reduction isn’t reflected on your next tax bill, follow up or appeal to PTAB within 30 days.

Can I skip the Assessor and go straight to the Board of Review?

Yes—direct to BOR is allowed. Some owners file both (Assessor → BOR) to maximize chances.

What if I miss both the Assessor and BOR windows?

If there’s a factual error in a prior year or a missed exemption, ask about a Certificate of Error to correct it retroactively.

What is PTAB and what’s the deadline?

PTAB is a statewide appeal body. You generally have 30 days from the BOR decision notice to file. Read PTAB’s filing instructions here.

About the Author

Harsha N Hegde is the founder of squaredeal.tax, a DIY platform that helps homeowners protest unfair property tax assessments. He has helped thousands of homeowners save money using comps-based evidence and practical guidance.

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Articles presented here are for general information and education only. It is provided as a courtesy to the general public. SQD Taxtech LLC does not warrant that it is accurate or complete. Opinions expressed and estimates or projections given are those of the authors or persons quoted as of the date of the article with no obligation to update or notify of inaccuracy or change. This article may not be reproduced, distributed or further published by any person without the written consent of SQD Taxtech LLC. Please cite source when quoting.

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