Cook County Property Tax Appeal Instructions

Thank you for using the RTA Appeal Service to help you submit your residential property tax appeal! Below are simple step-by-step instructions that you can use to submit your initial appeal in just a few minutes.

Step 1

Check to see if your initial appeal documents are ready by visiting your Order History.  These are prepared once your township is open for appeal, and you will not be able to complete the appeal process until these are ready.  You will receive an order update email once these are ready, and you can check the Appeal Calendar for all important dates.

Step 2

Visit the Cook County online appeal portal by clicking HERE (or visiting

Step 3

Enter your login credentials, or create an account if you are a new user.

Step 4

Once logged in, you will be taken to the Available Filings page. Select the option for CCAO Appeals – Real Estate Assessed Valuation Appeal (Residential).

Step 5

At the next screen, select Begin Filing.

Step 6

Enter your PIN in the appropriate box.  If you are uncertain of your PIN, it can be found in the document you downloaded from Step 1.

Step 7

You will now see the search results that should list your property. Please confirm, and then select Start Filing.

Step 8

If you are presented with a popup, select OK.

Step 9

In the Activity Window, review the information, select the two check boxes and select Next.

Step 10

In the Verify Parcel, review the information for accuracy and select Next.

Step 11

In the Primary PIN, do not check any of the boxes. Hit Next.

Step 12

In the Additional PINs, Select Next. You do not need to add any additional PINs.

Step 13

On Filer, assuming you are the homeowner of the property you are appealing, select Taxpayer/Owner in the first two drop downs as seen in the image. If your information does not populate in the additional boxes, check the box for “Check if Taxpayer/Owner name DOES NOT appear in the below selection” and fill in your information.

Step 14

The Property Characteristics shows all of the information that the County has on your property. Review and correct anything that may be incorrect. Then select Next.

Step 15

The Appeal Application is where we select that the appeal is based upon Lack of Uniformity / Comparables. Please ensure that you complete this page as follows:

  • For the Reason(s) for Appeal, select Lack of Uniformity / Comparables.
  • For the Lack of Uniformity/Comparables, enter “My assessed value is higher than many comparable properties.“.
  • For Field Check Required, select No.
  • For How is the Subject Property used? check Single Family.

Select Next.

Step 16

The Attachments screen requires you to upload the file with the PINs that we have prepared as comparisons for the justification of Lack of Uniformity. Please upload the file that you downloaded from step 1 above. Then select Next.

Step 17

The final screen, Submit, requires you to provide your name, phone number and email address. We also recommend that you print a draft of your filing before selecting Submit. Once you have done this, select Submit.

Step 18

When you see the confirmation popup, select Yes.

Step 19

Finally, you will receive an email with the confirmation to the email address that you used for registration on the site. Please keep that email as a record that your appeal was filed.