If the second-installment property tax bill for your home is missing an exemption, the Assessor’s Office can help you obtain a corrected bill or a refund. Learn how, get answers to questions, and apply online for a Certificate of Error.

Cook County is reassessed triennially, which means one-third of the county is reassessed each year. This year, the south suburbs will be reassessed. Your property may also be reassessed if there are significant changes due to a permit application, property division, demolition, or other special application.

To look up your property's township, visit the property's detail page, type in your property address or Property Index Number (PIN) and the township is listed. 

If your home was eligible for a homestead exemption in a prior tax year (2016, 2017, or 2018) and you already paid the full tax amount billed for that year, the Assessor’s Office can help you obtain a refund through the Certificate of Error process.

Your 14-digit Property Index Number (PIN) is printed on your tax bill, your property closing documents and deed, and notices from the Assessor's office (such as your assessment notice).

Your 14-digit Property Index Number (PIN) is printed on your tax bill, your property closing documents and deed, and notices from the Assessor's office (such as your assessment notice).