The Cook County Property Tax Appeal Process: A Complete Timeline and Checklist
Missing a deadline can cost you thousands. Here's everything you need to know about Cook County's appeal process and when to act.
Understanding Cook County's Triennial System
Cook County Reassesses in 3-Year Cycles
Cook County is divided into three assessment districts, each reassessed every 3 years:
North District
Reassessed: 2019, 2022, 2025, 2028...
Includes: Barrington, Evanston, Schaumburg, Wheeling, and others
South District
Reassessed: 2017, 2020, 2023, 2026...
Includes: Berwyn, Cicero, Oak Park, Orland Park, and others
City District
Reassessed: 2018, 2021, 2024, 2027...
Includes: All Chicago townships
Which Townships Are Reassessed When
Each district is further divided into townships. The reassessment schedule varies by township within each district. Check the Cook County Reassessment Schedule to find your specific township and upcoming reassessment years.
Why Your Assessment Might Jump Dramatically
During reassessment years, the county evaluates all properties in that district. If property values have increased significantly in your area over the past 3 years, your assessment could jump dramatically—even if your property hasn't changed.
Example: If your home was worth $300,000 in 2019 and is now worth $400,000, your assessed value could increase from $30,000 to $40,000 (10% of market value), leading to significantly higher property taxes.
Stage 1 - The Assessor's Office Appeal
When: Within 30 Days of Receiving Your Assessment Notice
This is your first opportunity to appeal. The clock starts ticking the day your assessment notice is mailed (check the date on your notice).
⚠️ Critical: You have exactly 30 days from the notice date. Missing this deadline means you cannot appeal for that tax year.
What Happens
- You file a formal appeal with the Assessor's office
- Provide evidence your assessment is too high (comparable sales, property issues, etc.)
- The Assessor reviews your case
- Decision typically within 30-60 days
Success Rate: Moderate - Many cases are resolved here, but many also move to the Board of Review if the reduction isn't sufficient.
Your Checklist
- ✓Note your appeal deadline date (30 days from notice date) - mark it in your calendar immediately
- ✓Gather 3-5 comparable sales (similar properties sold within last 12-18 months)
- ✓Take photos of any property issues (foundation problems, outdated systems, etc.)
- ✓Complete the appeal form (available on Cook County Assessor's website)
- ✓Submit before deadline (consider submitting early to avoid last-minute issues)
- ✓Keep copies of everything (forms, evidence, correspondence)
Stage 2 - Board of Review Appeal
When: If Unsatisfied with Assessor's Decision
If the Assessor doesn't reduce your assessment enough (or denies it), you can appeal to the Board of Review. You typically have 30 days after the Assessor completes their review, but check the Board of Review website for exact dates.
Important: The Board of Review publishes deadlines each year. These deadlines vary by township and are typically in late summer or fall.
What Happens
- More formal hearing process
- You present evidence to a 3-person board
- May be asked questions about your property
- Decision can take several months
Success Rate: Higher for well-documented cases. The Board of Review tends to be more thorough in their review.
Your Checklist
- ✓File appeal with Board of Review before their deadline
- ✓Prepare written testimony explaining why your assessment is too high
- ✓Organize all evidence and comparable sales in a clear, professional format
- ✓Attend your scheduled hearing (or send a representative if you can't attend)
- ✓Follow up on decision (can take 2-4 months after hearing)
Stage 3 - Circuit Court (If Necessary)
When: If Board of Review Denies Your Appeal
If the Board of Review denies your appeal and you believe they're wrong, you can take your case to Circuit Court. However, this is a significant step that requires careful consideration.
What Happens
- ⚖️This is litigation - you'll likely need an attorney
- ⚖️Formal court proceedings with legal rules and procedures
- ⚖️Can take 1-2 years to resolve
- ⚖️Legal costs involved (attorney fees, court costs, etc.)
Reality Check: Most homeowners stop at the Board of Review. Circuit Court is typically only for high-stakes cases where the potential savings justify the legal costs and time investment.
Critical Dates You Cannot Miss
Annual Timeline
Assessment Notices Mailed:
Typically mailed in the year your township is reassessed (every 3 years). Check your notice for the exact date.
Assessor Appeal Deadline:
30 days after your assessment notice is mailed
Board of Review Filing Opens:
Typically opens after Assessor completes review (varies by township, check Board of Review website)
Board of Review Deadline:
Typically 30 days after filing opens (exact dates published annually on Board of Review website)
Tax Bills Issued:
Usually issued in the fall, after appeals are resolved
How to Stay on Top of Deadlines
- 📅Mark your calendar as soon as you receive your assessment notice
- 📅Check the Board of Review website for exact filing dates
- 📅Set multiple reminders (1 week before, 3 days before, 1 day before)
- 📅Consider using a property monitoring service that alerts you to deadlines
What If You Miss a Deadline?
The Consequences
- ✗You cannot appeal for that tax year - The deadline is strict with no exceptions
- ✗You can appeal the following year - But only during the next reassessment cycle (3 years later)
- ✗You'll pay the higher taxes - In the meantime, you'll pay taxes based on the higher assessment
Set Calendar Reminders NOW for Next Cycle
If you've missed this year's deadline, don't make the same mistake next time:
- ✓Find your next reassessment year using the reassessment schedule
- ✓Set a reminder 1 month before your expected assessment notice
- ✓Start gathering evidence early so you're ready when the notice arrives
Pro Tips from Successful Appeals
- 💡Start gathering evidence immediately - Don't wait until you receive your notice. Research comparable sales and document property issues year-round.
- 💡Be specific and factual, not emotional - Focus on data: comparable sales, assessment ratios, property characteristics. Avoid emotional arguments about financial hardship.
- 💡Focus on comparable sales, not your financial situation - The assessor cares about market value, not whether you can afford the taxes.
- 💡Attend hearings in person when possible - Being present shows you're serious and allows you to answer questions directly.
- 💡Keep detailed records of everything - Save all forms, evidence, correspondence, and decisions. You may need them for future appeals.
- 💡Consider professional help for properties over $400k - The potential savings and complexity often justify the cost of a consultant.
Don't Want to Track All These Deadlines Yourself?
Sign up for our monitoring service and we'll alert you when it's time to appeal, plus provide the data you need to win.
This information is provided for educational purposes. For the most current information about Cook County's appeal process, visit the Cook County Assessor's Office or the Cook County Board of Review.