Frequently asked questions

A property tax appeal is a formal request to lower your property's assessed value. In Illinois, your property taxes are based on the assessed value set by the county assessor. If you believe your assessment is too high compared to similar properties, you can file an appeal with the Cook County Assessor or Board of Review. A successful appeal can reduce your assessment and lower your tax bill — though decisions are made by the county and there is no guarantee of a reduction.

A PIN (Property Identification Number) is a unique 14-digit number assigned to each property by the county assessor. In Cook County, you can find your PIN on your property tax bill or by searching the Cook County Assessor website. We use your PIN to look up your property, pull assessment data, and generate comparable sales for your appeal.

Cook County uses a township-based calendar. Each township has its own appeal window — typically you have 30 days from when your township's new assessments are published to file. Deadlines vary by township and year. OverTaxed IL tracks every township's window on the deadlines page and can email you a reminder before your window closes.

DIY Appeal Packet ($69 one-time per property): we build the comparable-property packet and filing guide; you file it yourself. Done-for-you ($97 one-time per property): we prepare the same packet and submit the appeal after you provide explicit authorization. Contingency cases are reviewed separately at 22% of first-year savings only if the county grants a reduction.

On the Done-for-you tier ($97) we submit on your behalf only after you sign explicit filing authorization. On the DIY Appeal Packet tier ($69) you file yourself at the Cook County Assessor or Board of Review portal — the packet is formatted so you can submit it in one focused session once your evidence is ready.

For a strong residential assessment appeal, comparable assessments are usually more important than raw sales alone: you want similar nearby properties assessed lower than yours. Sales evidence can also help, especially at the Board of Review. Our packet focuses on public-record comparable properties and explains which evidence fits your filing path.

Board of Review (BOR) Rule 15 governs what documents to file with your appeal (for example, copies of Assessor submissions, briefs, and other evidence). It is separate from how many comparable properties are persuasive. For class 2 residential properties, the packet should emphasize uniformity with comparable assessments and include any relevant sales or condition evidence.

After you submit at the Cook County Assessor portal, you'll receive a Filing ID and Docket Number by email — keep them for your records. The Assessor reviews your appeal (typically within a few months). If approved, your assessment is reduced and your next tax bill reflects the lower value. You can also check status at the Cook County portal. If denied, you can appeal again in a future year or to the Board of Review.

The county assessor or board of review decides appeals. Denials can happen for many reasons. OverTaxed IL does not guarantee a reduction — county decisions are final. We focus on building strong, evidence-backed appeals to improve your odds. You can always appeal again in a future year if your assessment changes.

We offer a procedural money-back guarantee on the DIY and Done-for-you packets: if your filing is rejected or denied solely because of an OverTaxed IL procedural error in the materials or submission we prepared, we refund the OverTaxed IL service fee. It does not cover county denials on the merits. Contact support@overtaxed-il.com within 30 days of the notice. See our Terms of Service for full details.

No. OverTaxed IL is not a law firm and does not provide legal or tax advice. We organize public Cook County records into the format the Assessor and Board of Review accept. For complex situations or legal advice, consult a licensed Illinois attorney or property tax consultant.

We're rolling out HOA / condo board support for the 2026 cycle. If your association manages multiple PINs and wants a bulk packet, use the HOA section on the homepage or email support@overtaxed-il.com — no attorney referral required.