Appealing your Cook County property tax assessment is one of the most financially productive things a Chicago homeowner can do — yet most people never attempt it because the process feels opaque. This checklist removes the mystery. Work through it phase by phase and you will have everything you need to file a complete, well-documented appeal. Print it, bookmark it, or walk through it digitally. Either way, do not let a missed deadline or a missing document stand between you and a lower tax bill.
How to use this checklist: Work through each phase in order. Phases 1 and 2 apply to every homeowner — even if you decide not to appeal, you will learn something important about your tax situation. Phases 3 through 5 walk you through actually filing and following up. The deadline table at the end gives you a calendar at a glance.
Phase 1: Verify Your Assessment
Before you can evaluate whether your assessment is correct, you need to understand what it actually says and what it implies about your property's value. This phase takes 20–30 minutes and requires only a computer and internet access.
Find Your Property Index Number (PIN)
☐ Locate your most recent tax bill or Notice of Proposed Assessment — your 14-digit PIN appears on both
☐ If you cannot find it, go to cookcountytreasurer.com and search by address
☐ Write your PIN down and keep it accessible — you will use it throughout this process
Pull Your Property Record Card
☐ Go to cookcountyassessor.com and search your PIN
☐ Review and verify: square footage (above grade)
☐ Review and verify: number of bedrooms and bathrooms
☐ Review and verify: lot size (if single-family home)
☐ Review and verify: basement (finished vs. unfinished vs. none)
☐ Review and verify: garage (attached/detached/none, number of spaces)
☐ Review and verify: property type classification (condo, SFH, multi-unit, etc.)
☐ Review and verify: construction year and quality rating
☐ Note any errors — even small ones can support a reduction
Calculate the Implied Market Value
☐ Find your current Assessed Value (AV) on your Notice of Proposed Assessment or the Assessor website
☐ Divide the AV by 0.10 (Illinois residential assessment level) to get the Assessor's implied market value
☐ Example: AV = $52,000 → Implied market value = $520,000
☐ Compare this number to what you believe your property would sell for today in the current market
Verify Your Exemptions
☐ On the Assessor website, confirm the Homeowner Exemption is applied (saves ~$700–$900/year)
☐ If you are 65 or older and own/occupy the property, check whether the Senior Exemption is applied
☐ Check whether a Senior Freeze exemption applies (locks in EAV for qualifying seniors)
☐ If you are a veteran with a service-connected disability, verify the Veterans exemption
☐ Apply for any missing exemptions at cookcountyassessor.com
AV ÷ 0.10 = Implied Market Value
AV × 2.9 (approximate equalization factor) = EAV
EAV − $10,000 (Homeowner Exemption) = Net EAV
Net EAV × 0.078 (approximate Chicago tax rate) = Estimated Annual Tax
Phase 2: Gather Evidence
Now that you know your assessment and its implied market value, you need evidence to support a lower value. This is the phase where the work is done. Strong evidence wins appeals; weak evidence rarely does.
Pull Comparable Sales
☐ Identify at least 3 and ideally 5 comparable sales for your property type
☐ Sales must be arm's-length (standard market transactions — not foreclosures, estate sales, or related-party transactions)
☐ Sales must have closed within the past 12 months
☐ Properties should be within approximately half a mile of your property
☐ Properties should be the same type (condo, townhome, SFH)
☐ Square footage should be within 20–25% of your property
☐ Similar bedroom/bathroom count, age, and construction quality
☐ For each comparable, note: address, sale date, sale price, square footage, beds/baths, PIN
Where to find comparables: Zillow and Redfin show recent sales publicly. For the most reliable and complete data, ask your real estate agent to pull a CMA (Comparative Market Analysis) from the MLS. The Camille Canales Group provides this for our clients as a standard service — reach out if you need it.
Document Property Condition and Errors
☐ If you found errors on the property record card, document them with photos and measurements
☐ Take photos of any deferred maintenance, structural issues, or condition factors that reduce value
☐ If you have repair estimates from licensed contractors, include them
☐ Photograph the exterior and key interior spaces — assessors rarely inspect interiors, so photographic evidence of condition matters
Gather Purchase Documentation (If You Bought Recently)
☐ Locate your HUD-1 or ALTA settlement statement showing the purchase price
☐ Have a copy of your fully executed purchase contract ready
☐ If your purchase price is lower than the Assessor's implied value, this is your strongest single piece of evidence
Consider an Appraisal (Optional)
☐ If the potential annual savings exceed $1,500–$2,000, consider ordering a licensed appraisal ($400–$600)
☐ Ensure the appraiser knows the purpose is property tax appeal — they will frame the report appropriately
☐ An appraisal is the single strongest form of evidence for a market value argument
Phase 3: File the Assessor Appeal
This is the first formal step. If you received a Notice of Proposed Assessment, you have 30 days from the notice date to file. Do not delay.
Pre-Filing
☐ Confirm the filing deadline (printed on your Notice of Proposed Assessment)
☐ Go to assessor.cookcountyil.gov and create an account or log in
☐ Have your PIN, evidence documents (PDFs preferred), and comparable sales data ready
Filing the Appeal
☐ Select the appeal type: comparable sales, property record error, or both
☐ Complete the comparable sales grid for each comparable property
☐ Enter your requested assessed value (your target AV = your estimated market value × 0.10)
☐ Upload all supporting documents in the format required by the portal
☐ Review everything before submitting
☐ Submit and save your confirmation number — screenshot or print the confirmation page
After Filing
☐ Log your submission date and confirmation number in a safe place
☐ Wait for the Assessor's decision — this typically takes 6–12 weeks
☐ You will receive a written decision by mail (and often visible online via your PIN)
Phase 4: File the Board of Review Appeal (If Needed)
If the Assessor denies your appeal or the reduction is not sufficient, file with the Cook County Board of Review during your township's open window. You can also file directly with the BOR in the same year without first filing with the Assessor, if the Assessor window has closed.
Determine Your Township Window
☐ Go to borc.cookcountyil.gov and find the current year's township appeal schedule
☐ Identify which township your property falls in (your PIN's first two digits identify the township)
☐ Note the open and close dates for your township's BOR window
Prepare Your BOR Submission
☐ Update your comparables if new sales have occurred since your Assessor appeal
☐ Include the Assessor's decision letter as part of your submission
☐ Complete the BOR complaint form (available on the BOR website)
☐ Assemble a clear, organized evidence packet — BOR reviewers handle many files
File and Follow Up
☐ File online at borc.cookcountyil.gov during your township's open window
☐ Save your confirmation number
☐ If a hearing is scheduled, appear prepared with copies of all your evidence
☐ The BOR decision typically arrives within several months of filing
Phase 5: Track Outcomes and Plan Next Steps
After the Assessor Decision
☐ Review the decision: did the Assessor reduce, maintain, or increase your assessment?
☐ If reduced to your satisfaction, monitor the new assessment reflected in your next tax bill
☐ If denied or insufficiently reduced, proceed to the Board of Review
After the Board of Review Decision
☐ Review the decision carefully
☐ If satisfied, verify the new assessment appears correctly in subsequent tax bills
☐ If not satisfied, evaluate whether PTAB is appropriate (consult an attorney)
☐ Note: PTAB filing deadline is 30 days from the BOR decision
Annual Review
☐ Check the BOR township schedule each year — you can appeal every year during the open window
☐ Keep track of new comparable sales in your area — fresh data strengthens future appeals
☐ Re-verify your exemptions each year to ensure nothing has lapsed
Deadlines at a Glance
Deadline / Event | When | Where to File / Check | Consequence of Missing |
|---|---|---|---|
Assessor Appeal | 30 days from Notice of Proposed Assessment | Forfeit Assessor-level appeal; BOR still available | |
Board of Review Appeal | During township's open window (check annually) | Must wait until next year's BOR window | |
PTAB Appeal | 30 days from BOR decision | Illinois PTAB (ptab.illinois.gov) | Forfeit PTAB option; Circuit Court may still be possible |
First Installment Tax Payment | March 1 (each year) | Penalty and interest on unpaid balance | |
Second Installment Tax Payment | Approximately August (check Treasurer site) | Penalty and interest on unpaid balance | |
Next Chicago Reassessment | 2027 | Watch for notice in mail | Missing Assessor window forfeits first-level appeal |
Quick Reference: Is Your Assessment Worth Appealing?
Yes Strong Basis to Appeal You bought recently below the implied value, comparables support a lower market value, or the property record card has errors. | Maybe Worth Investigating Your assessment feels high but you have not yet pulled comparables or checked the record card for errors. | Still Check Exemptions Even if the assessed value looks right, verify all your exemptions are in place. Missing ones are free to claim. |
The Most Valuable Thing You Can Do Today
Spend 30 minutes with this checklist. Pull up your property record card on the Assessor website, calculate your implied market value, and compare it to what you know about current prices in your neighborhood. If there is a meaningful gap — and for many Chicago homeowners there is — file the appeal. The worst outcome is that the Assessor disagrees. The best outcome is a reduction that saves you money every single year until the next reassessment.
Continue Reading
Part of the Camille Canales Group property tax education series:
→ Chicago Property Taxes Explained: Key Dates, Tools, and Expert Help
→ Cook County Reassessment Years: What Chicago Homeowners Need to Know
→ How to Appeal Your Cook County Property Tax Assessment: A Step-by-Step Guide
→ What a Successful Property Tax Appeal Actually Looks Like: A Logan Square Case Study
→ Property Tax Appeal FAQ: Every Question Chicago Homeowners Ask Us
Need Comparable Sales Data for Your Appeal?
The Camille Canales Group regularly helps Chicago homeowners pull MLS comparable sales for their property tax appeals. We can run a CMA for your property and help you evaluate your grounds for appeal — no charge, no obligation.
Camille Canales Group | Compass | ccg-chicago.com | 773-377-9200. This checklist is for informational purposes only and does not constitute legal or tax advice. Deadlines and procedures are subject to change; verify current information at assessor.cookcountyil.gov and borc.cookcountyil.gov.
