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Cook County Property Tax Appeal Guide (2026)
Follow this proven step-by-step process to successfully challenge your Cook County property assessment and potentially save thousands on your property tax bill.
Varies
Filing Deadline by Township
FREE
Filing Fee
Online
Preferred Filing Method
Important Timeline Information
Cook County has a unique reassessment schedule. Chicago properties are reassessed annually, while suburban townships follow a triennial cycle. Filing periods are announced by township and typically last 30 days. Check the Cook County Assessor's website for your township's filing period.
3 Steps to File Your Appeal
Follow this proven process to successfully challenge your Cook County property assessment and maximize your chances of a successful reduction. Understanding Cook County's two-tier appeal system is critical to your success.
Gather Your Evidence
Collect comprehensive documentation that proves your property is overassessed compared to similar properties in your neighborhood. Cook County appeals require strong comparable sales evidence and documentation of any property condition issues.
File Your Appeal Online
Submit your appeal through the Cook County Assessor's Office online portal during your township's filing period. The online system allows you to upload supporting documentation and track your appeal status.
Attend Your Hearing
Present your case to the Cook County Board of Review if your initial appeal is denied or you're unsatisfied with the result. The Board of Review provides an independent hearing process with commissioners who evaluate your evidence.
Complete Filing Guide
Follow these detailed steps to successfully file your property tax appeal in Cook County. Each step includes specific requirements and important information about Cook County's unique two-tier appeal process.
Gather Your Evidence
Our Competitive Market Analysis will provide a strong foundation for your appeal, but you can supplement it with additional documentation for an even stronger case:
Evidence Checklist:
Pro Tip for Cook County Appeals
Cook County uses market value assessments at 10% for residential properties. Our Comparative Market Analysis (CMA) accounts for this and provides the specific comparable sales evidence that Cook County hearing officers and Board of Review commissioners expect to see. Strong comparable sales data is the most effective evidence in Cook County appeals.
File Your Appeal with the Assessor's Office
Complete and submit your appeal through the Cook County Assessor's Office online portal during your township's filing period. This is the first level of the appeal process.
Critical Filing Period Warning
Missing your township's filing period means you cannot appeal your assessment that year. Filing periods are announced by township and typically last 30 days. Monitor the Cook County Assessor's website closely for your township's dates. Chicago residents should note that annual reassessments mean annual appeal opportunities.
Filing Requirements:
Understanding Cook County's Two-Tier Appeal System
Cook County has a unique two-tier appeal process. First, you file with the Assessor's Office during the reassessment year. If you're unsatisfied with that decision, you can file a second appeal with the independent Board of Review. Many successful appellants use both levels to achieve maximum reductions.
File with the Board of Review (Second Level)
If your appeal with the Assessor's Office is denied or you're unsatisfied with the result, file a second-level appeal with the Cook County Board of Review.
Board of Review Process
The Board of Review is an independent body that conducts formal hearings. After the Assessor's decisions are published, the Board of Review opens for filings. You'll receive a hearing date by mail where you present your evidence to commissioners. This is often where significant reductions are achieved, especially if you have strong comparable sales evidence.
Board of Review Filing Requirements:
Board of Review Hearing Best Practices
Board of Review hearings are formal proceedings. Prepare a clear, concise presentation focusing on your strongest comparable sales. Commissioners appreciate factual evidence over emotional arguments. Practice your presentation beforehand and be ready to answer questions about property characteristics, sale conditions, and market trends in your neighborhood.
Receive Your Decision
Both the Assessor's Office and Board of Review will mail decisions after reviewing your appeal and conducting hearings.
What to Expect:
Success Timeline and Future Appeals
Successful appeals in Cook County can take 6-12 months to complete through both tiers. Your reduction will be reflected on your next tax bill. Keep all documentation for future appeal years, as assessments can increase again in subsequent reassessment cycles. Many Cook County homeowners file appeals each reassessment period to maintain fair assessments.
Cook County Triennial Reassessment Schedule
Understanding when your property is reassessed is critical for planning your appeal. Cook County follows a three-year cycle for most townships.
North Suburbs (2024 Reassessment Year)
Townships: Barrington, Elk Grove, Hanover, Leyden, Maine, New Trier, Northfield, Palatine, Schaumburg, Wheeling
South and West Suburbs (2025 Reassessment Year)
Townships: Berwyn, Bloom, Bremen, Calumet, Cicero, Lemont, Lyons, Oak Park, Orland, Palos, Proviso, Rich, Riverside, Stickney, Thornton, Worth
City of Chicago (Annual Reassessment)
Chicago properties are reassessed every year, providing annual appeal opportunities for city residents.
Cook County Quick Facts
Filing Method
Online Portal (Preferred) or Mail
Filing Fee
FREE for Residential Properties
Deadline
Varies by Township (30-day windows)
Appeal Levels
Two-Tier: Assessor + Board of Review
Reassessment Cycle
Triennial (Chicago: Annual)
Hearing Format
In-Person or Video Conference
Need More Information?
For complete Illinois property tax information including rates, exemptions, and appeal processes for other counties, visit our Illinois property tax guide. Abode Money is the best property tax protest company in IL.
Don't Miss Your Township's Filing Period
Cook County's township-based filing periods mean timing is critical. Start your appeal today to ensure you're ready when your filing window opens.
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