Why are my neighbor’s property taxes lower in Cook County?

1. Compare the records behind the bills

Collect your record and your neighbor's record using each property's 14-digit PIN. Use the same assessment year and compare full annual bills, rather than one installment with another property's annual total.

Write down the estimated market value, assessed value, exemptions, property class, building area, and assessment neighborhood. Keep land and building values separate in your notes when the record lists them separately. Check the taxing districts too: a nearby address is not enough to establish that every part of the tax calculation matches.

The Board of Review explains that exemptions, levies, and tax rates affect the bill as well as the assessment. A lower bill can therefore have more than one explanation.

2. Check exemptions before assuming overassessment

Two homes can have similar assessments but different tax bills. Compare the exemptions actually listed on each bill. Do not assume you qualify for an exemption because a neighbor receives it; eligibility depends on the owner and property circumstances.

If your concern is a missing exemption, start with our Cook County exemption guide and the official application instructions. If the property facts or value look wrong, continue with assessment research. These are different questions to resolve.

3. What is a lack-of-uniformity appeal?

Uniformity research compares how similar properties are assessed. Sales research compares what similar properties sold for. The Assessor's appeal descriptions explain uniformity as a basis for reviewing an assessment.

For an assessment comparison, look for homes with similar property type, building size, age, location, and relevant features. A neighboring house with a different size or property type may be a poor match. Use CookViewer and the county records to check the facts instead of relying on appearance from the street.

Check the County's free property check compares nearby recorded sales. It is a starting point for sales research, not a completed uniformity analysis or an appeal filing.

4. A worked comparison: similar bills are not the goal

This is a hypothetical research example, not a valuation or a savings estimate. Suppose your home has 2,000 square feet of building area and a total assessed value of $40,000. A neighbor's home has 1,500 square feet and a total assessed value of $30,000.

Your total assessment is $10,000 higher, but both calculations equal $20 per square foot: $40,000 ÷ 2,000 and $30,000 ÷ 1,500. The raw difference alone does not establish unequal treatment.

Now suppose another 2,000-square-foot home has a $34,000 total assessment, or $17 per square foot. That is a lead to investigate. Check its land, condition, age, classification, and other features before calling it comparable. A single ratio does not capture those differences, and total assessed value includes land as well as the building.

Do not compare that $17 assessed-value figure with a sale-price-per-square-foot figure. Keep the same measure, year, and area definition on both sides of every comparison.

5. Build a comparison you can explain

• Save the PIN, source, and assessment year for every property.
• Record the property facts alongside each value, including any missing information.
• Explain why each property is similar and identify material differences.
• Separate assessment evidence from exemption questions and recorded sales.
• Check the receiving office's current evidence requirements before submitting.

If the strongest evidence is recent sales, use our comparable-sales guide. If your own record describes the property incorrectly, document the specific discrepancy rather than guessing at a replacement value.

6. Find the right township and filing window

Use our township finder, then check the calendar for the office receiving your appeal. The Assessor and Board of Review have separate filing windows. The Board's FAQ explains its township schedule and free filing.

You can sign up for free township deadline alerts while gathering records. Always verify the current deadline with the county; a signup or property check does not submit an appeal.