Chicago Property Tax Appeals Guide

How to appeal your property tax in Cook County and the Chicago suburbs through the Board of Review and PTAB.

How to Appeal Your Property Tax Assessment in Cook County and the Chicago Suburbs

Property taxes in the Chicago metro are among the highest in the nation. Cook County's effective rate averages approximately **2.1%**, and many suburban townships are even higher. On a median-priced home of $300,000, that's **$6,300/year** — and rising.

But there's a compelling reason to appeal: the Cook County Assessor's office has faced well-documented criticism over inequitable assessment practices. A landmark ProPublica Illinois investigation — "The Tax Divide" — found systematic patterns of over-assessing lower-value homes while under-assessing higher-value properties. This documented inequity means many Chicago-area homeowners are paying more than their fair share.

The Cook County Appeal Process

Cook County has a **multi-step appeal process** that gives homeowners multiple chances to reduce their assessment:

Step 1: Appeal to the Cook County Assessor When your township is reassessed (Cook County reassesses on a triennial cycle by geographic area), you can file an appeal directly with the Assessor's office during the open appeal period. This is the first opportunity and is free to file.

Step 2: Appeal to the Cook County Board of Review (BOR) After the Assessor finalizes values, the Board of Review opens a separate appeal window — organized by township. **The BOR filing window is township-specific**, meaning your deadline depends on which township your property is in. Check the BOR website for your township's specific dates.

The BOR review is more formal. You submit evidence (comparable sales, photos, condition documentation), and the BOR makes an independent determination.

Step 3: Appeal to the Illinois Property Tax Appeal Board (PTAB) or Circuit Court If you disagree with the BOR's decision, you can file a further appeal with the state-level PTAB. This is a more formal administrative process. Alternatively, you can appeal to the Circuit Court of Cook County.

Evidence That Wins Appeals

The strongest Cook County appeals include:

• **Comparable sales**: Properties similar to yours (size, age, condition, neighborhood) that sold recently for less than your assessed value. The Assessor's office uses a classification system — understanding your property's class helps you select appropriate comps.
• **Property condition documentation**: Photos of needed repairs, foundation issues, roof age, outdated systems. The Assessor can't see inside your home from a desk review.
• **Assessment inconsistency data**: If similar properties on your block are assessed at lower values per square foot, this is powerful evidence. ProPublica's analysis showed this kind of inconsistency is common in Cook County.
• **Market analysis**: If recent comparable sales demonstrate that the market has cooled from the values used in your assessment, present the data clearly.

Suburban Counties: Separate Processes

The Chicago metro extends across multiple counties, each with its own assessment and appeal process:

• **DuPage County**: Quadrennial reassessment cycle. Appeals go to the DuPage County Board of Review.
• **Kane County**: Quadrennial reassessment. Kane County Board of Review handles appeals.
• **Lake County**: Quadrennial reassessment. Lake County Board of Review.
• **Will County**: Quadrennial reassessment. Will County Board of Review.

Each suburban county has its own deadlines, typically 30 days from the date of your assessment notice. The evidence requirements are similar to Cook County, but the processes are generally simpler due to smaller scale.

Exemptions Chicago Homeowners Should Claim

Illinois offers several property tax exemptions that many homeowners miss:

• **Homeowner exemption**: Reduces the Equalized Assessed Value (EAV) by up to $10,000 for owner-occupied primary residences.
• **Senior citizen homestead exemption**: Additional $8,000 EAV reduction for homeowners age 65+.
• **Senior freeze (Senior Citizens Assessment Freeze)**: Freezes the EAV at the base year level for qualifying seniors (age 65+ with household income below a threshold, currently approximately $65,000). This can be enormously valuable during periods of rising assessments.
• **Home improvement exemption**: Excludes up to $75,000 of increased value from qualifying home improvements for 4 years.
• **Disabled veterans exemption**: Various levels of exemption based on disability rating.

**Critical**: These exemptions are not automatic. You must apply for each one, and some require annual renewal.

Frequently Asked Questions

How often is my property reassessed in Cook County? Cook County uses a triennial (3-year) reassessment cycle, organized geographically. The north suburbs, south suburbs, and city of Chicago are each assessed in separate years. Check the Assessor's website to confirm when your area was last reassessed.

Is it worth hiring a property tax attorney in Cook County? For properties assessed above $250,000, many homeowners find that a tax attorney or tax reduction firm — typically working on contingency (30–50% of first-year savings) — provides strong ROI. They bring experience with the BOR process and access to comparable data. For lower-value properties, self-representation is often effective.

What is the ProPublica "Tax Divide" and does it help my appeal? ProPublica Illinois published "The Tax Divide" investigation documenting systematic inequities in Cook County assessments — specifically, over-assessment of lower-value properties relative to higher-value ones. While citing the investigation itself isn't direct evidence, the underlying assessment inconsistency patterns it documented can support your appeal if you can show similar properties in your area are assessed at lower rates.

Can I appeal every year in Cook County? You can appeal during every reassessment cycle (every 3 years in Cook County). You can also appeal to the Board of Review in the years between reassessments if you believe your assessment is incorrect relative to market value or comparable properties.

---

[Get Your Free Savings Report for Chicago](/start)

**Related**: [Chicago Home Insurance Guide](/guides/chicago/home-insurance-savings) | [Chicago Flood Insurance Guide](/guides/chicago/flood-insurance-savings) | [Back to Chicago Hub](/guides/chicago)

Get early access

We're expanding our partner network here. Join the early-access list — typical activation within 30 days.