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How Much Can You Save by Appealing Your Illinois Property Taxes?

March 22, 2026

The question every homeowner asks before starting a property tax appeal: is it actually worth it?

Short answer: almost always yes. Here's what the numbers look like.

Average Savings for Cook County Homeowners

Based on Cook County Board of Review data, homeowners who appeal their assessments see reductions on a majority of cases filed. Average annual savings range from:

These are annual savings — meaning every year until the next reassessment cycle (every 3 years in Cook County), you pay less.

The Math on a Successful Appeal

Let's say you own a home assessed at $85,000 (triennial assessed value). The Assessor is claiming your home is worth $850,000.

If comparable homes in your area sold for $700,000, your assessed value should be closer to $70,000.

That $15,000 reduction in assessed value translates to roughly $1,500–$2,000 less per year on your tax bill, depending on your local tax rate.

What Increases Your Chances of Saving More

Strong comparable sales data. The more recent and similar the sales, the stronger your case. Homes that sold in the same neighborhood, similar size, similar age, similar condition — within the last 12 months — carry the most weight.

Reassessment years. If your township is in a reassessment year (like South District townships in 2026), values are being recalculated fresh. This creates the biggest opportunity for corrections.

Acting quickly. Appeals filed early in the window tend to get more attention than last-minute filings. Don't wait until the deadline.

What Does It Cost to Appeal?

Filing with the Assessor: Free.

Filing with the Board of Review: Free.

Using Overtaxed IL: Starts at $149/property/year — which pays for itself many times over if you achieve even a modest reduction. Our Starter plan includes full automation, comparable property analysis, and filing assistance.

We also offer a Performance Plan — you pay nothing until you save. We take 4% of your 3-year tax savings. Zero risk.

Ready to See Your Numbers?

Run a free assessment check at overtaxed-il.com/check. Enter your address and we'll show you what comparable properties are assessed at and estimate your potential savings in about 60 seconds.