To file an Illinois property tax appeal, submit a complaint to your county Board of Review within 30 calendar days of the date your township’s annual assessment list is published. In Cook County, you get a second bite first: you can appeal to the Cook County Assessor’s Office before the Board of Review window opens for your township. A successful appeal lowers your tax bill for that year and typically for the remaining years of the reassessment cycle.
The 30-Day Deadline That Decides Everything
The statutory window is 30 calendar days after the assessment list is published in a local newspaper.1LaSalle County. LaSalle County Board of Review Rules and Procedures The clock runs from the publication date, not from when a notice reaches your mailbox or when you first notice the listing. Townships are reassessed on a rolling basis, so the exact date is different for every township and changes year to year. Your county assessor or Board of Review posts the dates.
Miss the window and you lose the right to appeal for the entire assessment cycle. There is no late-filing exception at the Board of Review. If the deadline is close, file with whatever you have; most boards accept supplemental evidence after a timely complaint has been docketed.
Cook County publishes a separate, township-by-township calendar covering both the Assessor’s Office window and the later Board of Review window.2Cook County Board of Review. Dates and Deadlines Those two deadlines are distinct, and the second one does not reopen the first.
What You’re Actually Arguing
Illinois recognizes three grounds for challenging an assessment, and your evidence should track whichever one fits.
- Overvaluation. The assessor set your fair cash value higher than the property is actually worth. Recent comparable sales, a professional appraisal, or your own recent purchase price are the usual proof.
- Lack of uniformity. Your property is assessed at a higher percentage of its value than similar nearby properties. You do not have to prove your home’s precise market value, only that your assessment is out of line with comparable homes.
- Factual errors. The assessor’s property record card is wrong about your home — square footage, bathroom count, basement finish, construction type. Fixing the record fixes the number.
Where to File: Cook County vs. the Rest of Illinois
Cook County is the only Illinois county that gives you two chances before the state-level board. The first is with the Cook County Assessor’s Office, which opens an appeal window for each township after reassessment notices go out. You can file online through the Assessor’s portal, upload evidence, and get a docket number by email.3Cook County Assessor’s Office. File an Appeal Online The Assessor’s Office may reduce the assessment before the file ever moves to the Board of Review.
After the Assessor rules, the Cook County Board of Review opens its own window for that township. You can file there whether or not you filed with the Assessor, and whether or not the Assessor granted a reduction.4Cook County Assessor’s Office. Assessment and Appeal Calendar Most experienced Cook County appellants file at both levels.
Everywhere else in Illinois, there is no Assessor-level appeal. You file directly with your county’s Board of Review.
Evidence That Actually Moves the Needle
A one-page form claiming your taxes are too high will go nowhere. What boards respond to depends on which ground you are arguing.
For Overvaluation
The strongest evidence is recent sale prices of comparable homes — similar size, age, construction, and neighborhood, ideally sold in the last year or two. If you recently bought the property, the closing disclosure or settlement statement shows exactly what a buyer paid on the open market.5Madison County. Tips for a Successful Appeal
A professional appraisal conducted in conformance with the Uniform Standards of Professional Appraisal Practice (USPAP) carries real weight. Expect to pay $300 to $600 for a standard residential appraisal; complex or unusual properties cost more. Use a licensed Illinois appraiser and a recent appraisal. A report from several years ago will not persuade the board that today’s number is wrong.
For Lack of Uniformity
Pull assessed values and property details for three to five similar homes in your area that are assessed at lower levels than yours. The Cook County Board of Review wants properties similar in size, construction type, age, materials, and condition, preferably on the same block or within a block or two.6Cook County Board of Review. How to Present a Case Based on Lack of Uniformity The same approach works in other counties.
For Factual Errors
Download your property record card from the assessor’s website and check every line against reality: square footage, lot size, bedrooms and bathrooms, materials, basement finish. Note each error on the appeal form and attach photographs documenting the actual condition.
General Tips
Front-of-property photographs are required by some boards and helpful everywhere. Photos of comparables strengthen uniformity arguments; pictures of water damage, foundation issues, or deferred maintenance support overvaluation claims. Organize everything so each document maps directly to the argument on the form. A board member reviewing dozens of appeals in a day will not dig through a disorganized pile.
Submitting the Appeal
In Cook County, both the Assessor’s Office and the Board of Review accept online filings through their portals. You can save a draft, add attachments later, and submit when ready; submission generates an email confirmation and a docket number.3Cook County Assessor’s Office. File an Appeal Online Outside Cook County, check whether your Board of Review takes electronic filings. Many smaller counties still require paper.
For paper filings, boards typically require an original signed complaint plus one or two copies of all supporting documents.7Tazewell County Board of Review. 2025 Rules and Procedures Manual Send packets by certified mail with return receipt, or deliver in person and get a date-stamped copy. Appeal forms require your Property Index Number (PIN), a 10- to 14-digit identifier on your tax bill or assessment notice.8Cook County Assessor’s Office. Residential Appeal Form If you cannot find the PIN, most assessor websites let you search by address.
The Hearing
Once your complaint is docketed, the Board of Review will either decide on the written evidence or schedule a hearing. If your complaint complies with the rules, you will receive a hearing notice, and the board may allow participation by phone or video.7Tazewell County Board of Review. 2025 Rules and Procedures Manual Hearings run 10 to 20 minutes. Lead with your strongest evidence, present it in the same order as your written submission, and expect questions about your comparables or appraisal.
If the complaint has technical defects, the board must notify you and give at least 10 business days to fix them. Written decisions usually arrive by mail in January or February of the year after filing, stating whether the assessment was sustained, reduced, or raised.
If You Lose: The Property Tax Appeal Board
The next step after an unsatisfactory Board of Review decision is the Illinois Property Tax Appeal Board (PTAB). File your petition within 30 days of the postmark date on the Board of Review’s written decision.9Property Tax Appeal Board. Frequently Asked Questions This deadline is absolute.
PTAB conducts a fresh review and is not limited to the evidence you presented at the county level, so you can add new comparables, an updated appraisal, or other documentation.10Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/16-180 The process is intentionally informal.
For residential appeals seeking a change of less than $100,000 in assessed value, PTAB requires at least three comparable properties in a grid analysis, or a complete appraisal, or recent sale documentation.11Property Tax Appeal Board. Filing Your Appeal Submit one copy of the petition, one copy of the Board of Review’s final decision, and one set of all supporting evidence. If documentation exceeds 500 pages, three collated sets are required. Attorney-represented appellants must file through PTAB’s eFiling Portal.12State of Illinois. Property Tax Appeal Board
PTAB decisions bind both the taxpayer and government officials. The board can only determine the correct assessed value; it cannot change your tax rate, review the tax bill itself, or decide exemption eligibility.12State of Illinois. Property Tax Appeal Board
Circuit court is an alternative to PTAB, not an addition. If you file with PTAB for a given tax year, you cannot also file a tax objection in circuit court for the same year’s valuation. The circuit court route requires paying all taxes due within 60 days of the final installment’s penalty date, filing within 75 days of that penalty date, paying a filing fee of roughly $376 per parcel, and meeting a clear and convincing evidence standard. It is better suited to high-value commercial cases than typical residential appeals.
What the Whole Thing Costs
Filing with the Board of Review is free in most Illinois counties. PTAB charges a small filing fee and is designed to be accessible without a lawyer. The real cost is the evidence. A professional appraisal runs $300 to $600 for a standard single-family home. Build the case using public comparable sales data and your own photographs and your out-of-pocket cost at the Board of Review can be near zero.
Property tax attorneys and consultants commonly work on contingency, charging 25 to 35 percent of the first year’s tax savings. On a $2,000 annual reduction, that is $500 to $700. If the appeal fails, you owe nothing. Run the math before signing: on a modest reduction, the contingency fee can consume most of year one’s savings. The reduction itself usually carries forward until the next reassessment, so years two through four of the cycle are pure savings.
After a Successful Appeal
A reduced assessment rarely produces an instant refund check. If the decision comes before the final tax bill is calculated, the lower value is baked into the bill and you simply pay less. If the bill has already been issued and paid at the higher amount, you may be owed a refund or credit. Timing and process vary by county; Cook County’s Treasurer handles certain refunds automatically when the office can identify who made the overpayment.
If your mortgage includes an escrow account, a lower tax bill means your servicer is collecting more each month than it needs. Federal law requires an annual escrow analysis and a statement within 30 days of the end of your escrow computation year.13Consumer Financial Protection Bureau. 12 CFR 1024.17 Escrow Accounts A surplus should either lower your monthly payment or come back as a refund. You do not have to wait for the annual review. Call the servicer after receiving confirmation of the reduced assessment and ask for an early escrow analysis. Many will accommodate the request, though they are not required to do so outside the annual cycle.
Check Your Exemptions First
Before investing time in an appeal, confirm you are receiving every exemption you qualify for. Missed exemptions are common, and claiming an overlooked one can cut your bill faster than a contested appeal. The General Homestead Exemption, Senior Citizens Homestead Exemption, and Senior Citizens Assessment Freeze are the three most frequently missed; the Illinois Department of Revenue publishes current amounts and eligibility rules.14Illinois Department of Revenue. Property Tax Exemption Information Exemptions and an appeal are not mutually exclusive. You can apply for a missing exemption and file an assessment appeal at the same time.