Cook County property tax bills are due in two installments each year
Cook County splits property tax payments into two bills: the first installment is due March 31, and the second is due September 30. Both dates are firm important date — if your payment arrives after these dates, the county assesses a penalty. You will receive a bill in the mail before each due date, though the exact timing varies depending on your address within the county.
The first bill covers taxes assessed from January through June, and the second covers July through December. If you own property in Cook County, you are responsible for paying both installments, even if you have a mortgage. Your lender may handle these payments through an escrow account, but you should verify this with your loan servicer rather than assume it is being paid.
If you miss a due date, penalties begin to accrue when ready. Cook County charges a 1.5 percent penalty on the first installment if it is not paid by March 31, and another 1.5 percent on the second installment if it is not paid by September 30. After six months of non-payment, additional interest and costs accumulate, and the county can eventually place a lien on your property or sell the tax bill to a third party.
Key Takeaways
- Cook County property taxes are due twice yearly: March 31 for the first installment and September 30 for the second.
- A 1.5 percent penalty applies to any payment received after the due date, and additional interest accrues if the bill remains unpaid for six months.
- You can pay online through the Cook County Treasurer's website, by mail, in person, or through automatic bank withdrawal.
- If you have a mortgage, your lender may pay taxes through escrow, but you should confirm this rather than assume it is handled.
- If you cannot pay by the due date, contact the Cook County Treasurer's office to discuss payment arrangements before penalties begin.
How to pay your Cook County property taxes
The Cook County Treasurer's office offers four main payment methods. The fastest and most convenient is online payment through the Cook County Treasurer website — you can pay with a debit card, credit card, or electronic bank transfer. Online payment typically processes the same day if submitted before 11:59 p.m., though credit card payments may carry a processing fee.
You can also mail a check or money order to the Cook County Treasurer's office. Include your property index number (PIN), which appears on your tax bill, so the payment is credited to the correct account. Mail payments should arrive well before the due date to account for postal delays — mailing on the due date itself is risky.
If you prefer to pay in person, the Treasurer's office accepts walk-in payments at its downtown Chicago location and at satellite offices in some suburban areas. Call ahead to confirm hours and locations, as these can change seasonally. You can also set up automatic monthly payments through your bank, which spreads the tax bill across the year and removes the risk of missing a important date.
What happens if you pay late
A 1.5 percent penalty is added to any payment received after March 31 or September 31. This penalty is calculated on the full amount owed, not just the portion that is late. For example, if your second installment is $2,000 and you pay on October 15, you owe $2,030 — the original $2,000 plus a $30 penalty.
If your bill remains unpaid for six months after the due date, Cook County adds interest at a rate set by state law, which is currently around 1 percent per month. After approximately two years of non-payment, the county can sell your tax bill to a third-party tax buyer, who then has the right to foreclose on your property if the debt is not paid within a set period. This process is separate from mortgage foreclosure and can happen even if your mortgage is current.
If you know you cannot pay by the due date, contact the Cook County Treasurer's office before the important date. The office does not have broad authority to waive penalties, but it can discuss payment plans or other options depending on your situation. Waiting until after the important date to contact them will not stop the penalty from being assessed.
Understanding your property tax bill
Your Cook County property tax bill lists your property index number (PIN), the assessed value of your property, the tax rate applied by your municipality and school district, and the amount due for that installment. The bill also shows the due date, the penalty amount if paid late, and payment instructions. Keep this bill for your records — you will need the PIN to make online payments or to contact the Treasurer's office about your account.
The assessed value on your bill may differ from the market value of your home. Cook County reassesses properties every three years, and the assessed value is used to calculate your tax bill. If you believe your property has been assessed incorrectly, you can file a challenge with the Cook County Assessor's office, though this process is separate from paying your current bill and does not delay the due date.
If you own property through a trust or business entity
If your property is held in a trust, LLC, or other business structure, you are still responsible for paying property taxes by the same important date. The bill will be addressed to the entity name, but the tax obligation remains. Make sure the Treasurer's office has current contact information for whoever manages the property, so bills are received and paid on time.
If you have recently inherited property or taken ownership through a trust, contact the Cook County Assessor's office to may support the deed has been recorded and the bill is being sent to the correct address. New owners sometimes do not receive bills because the Assessor's records have not been updated, which can lead to unintentional late payments.
Payment options for homeowners with mortgages
If you have a mortgage, your lender may require you to pay property taxes through an escrow account. This means you pay a portion of the estimated annual tax bill each month along with your mortgage payment, and the lender pays the county on your behalf. This protects the lender's interest in the property by ensuring taxes are paid.
Even if your lender handles tax payments, you should receive a statement showing what was paid and when. Review this statement against your Cook County tax bill to confirm the amounts match. If your lender fails to pay or underpays, you are ultimately responsible for the penalty and interest, even though you sent the money to the lender. If you discover a problem, contact your lender when ready and provide documentation to the Cook County Treasurer's office.
Frequently Asked Questions
What if I did not receive my property tax bill in the mail?
Contact the Cook County Treasurer's office with your property index number (PIN). They can confirm whether a bill was mailed and provide the amount due. You can also look up your account online through the Treasurer's website. Not receiving a bill does not extend the due date — you are still responsible for paying by March 31 or September 30.
Can I pay my property taxes online with a credit card?
Yes, the Cook County Treasurer's website accepts credit and debit card payments. Be aware that credit card payments typically include a processing fee of 2 to 3 percent, which is added to your bill. Electronic bank transfers through the same website do not carry this fee.
What is the property index number and where do I find it?
The property index number (PIN) is a unique identifier assigned to your property by Cook County. It appears on your property tax bill, your mortgage documents, and your property deed. You need this number to pay online or to contact the Treasurer's office about your account.
Can I set up a payment plan if I cannot pay the full amount by the due date?
The Cook County Treasurer's office can discuss your situation if you contact them before the due date, but the office has limited authority to defer payment. A penalty will still be assessed on any amount paid after the important date. Contact the office directly to learn what options may be available based on your circumstances.
Do I have to pay property taxes if I am selling my home?
Yes, property taxes are the responsibility of the owner on the due date, regardless of whether the property is being sold. At closing, the seller and buyer typically split the year's taxes based on the number of days each owned the property. Your real estate attorney or title company will handle this calculation, but you remain responsible for paying your portion by the Cook County important date.