The homeowner's reading room
Why did my Cook County property tax bill go up?
A higher bill is a reason to check the records, but it does not tell you which part changed. Start with the same tax year and the full annual amount, then work through the assessment, exemptions, and tax rate.
1. Compare annual bills, not just installments
Find the tax year printed on each bill and put both installments together before comparing one year with another. Keep the payment year separate from the tax year. A mortgage escrow change is another number again; use the county bill to isolate the property tax itself.
The Cook County Treasurer explains that the first installment is 55% of the prior year's total, while the second settles the balance and includes exemptions. The two installments are not meant to be equal.
Last year's total was $6,000. A first installment of $3,300 and second installment of $3,600 add up to $6,900 this year: a $900 annual increase, or 15%. Comparing the $3,600 second installment only with the $3,300 first installment answers a different question.
Write down: tax year, first installment, second installment, annual total, and the difference from the previous year. Use the same PIN on both bills.
2. Separate the assessment from the tax bill
A reassessment notice estimates property value; it is not a demand for payment. A higher assessment does not mean the bill rises by that same percentage. The Assessor explains that assessed value, exemptions, and the tax rate all affect the bill, and local taxing bodies' levies also matter. See its notice and tax bill explanation.
Compare the county's estimated market value with evidence about your home. Do not compare your total bill with a neighbor's total and assume the difference proves your assessment is wrong. Start with the property facts and relevant valuations.
Our assessment notice walkthrough explains which numbers to copy into your notes.
3. Check whether an exemption is missing
Compare the exemptions listed for each tax year. A missing exemption and an excessive valuation need different follow-up. Mark the specific exemption you expected and the year it is absent; do not assume eligibility from a prior owner's record.
The Assessor provides a Certificate of Error process for eligible missing exemptions on previously issued bills. Applications can be denied, so check the current tax years, eligibility, and required documentation. Our exemptions guide is a starting point for that review.
4. Choose the next step that fits the problem
- The annual total is higher: compare the assessment, exemption entries, and tax rate line by line. Record what actually changed before deciding on a remedy.
- The property record looks wrong: note the incorrect field, the correct information, and the document that supports it.
- The estimated market value looks too high: research comparable sales and check your township's filing window.
- The payment or account record is unclear: start with the Treasurer's official site and your bill.
Keep a short record of the issue, the office you contacted, and any confirmation number. That makes it easier to follow up without starting the explanation over.