Property-tax appeals in Illinois
Deadlines, evidence, and a packet you file yourself — for homes, multifamily, and commercial property in Illinois.
State rules verified from public sources| Deadline rule | Non-Cook County: 30 calendar days after the assessment list is published. Cook County: each township opens for Board of Review appeals for roughly 30 days on a township-by-township schedule |
|---|---|
| First hearing body | Cook County Board of Review (Cook County); escalation to the Property Tax Appeal Board (PTAB) or Circuit Court |
| Who may represent you | Cook County Board of Review Rule 1: only licensed attorneys and individual taxpayers representing themselves may practice before the Board; entities such as corporations and LLCs must be represented by an attorney |
CAN RAISE VALUE (Cook County evidence): an aggregation of Cook County Board of Review open data found 0.18% of BOR appeals in 2021-25 ended in an increase - increases are possible but rare; this is county data, not a statewide statutory rule. Assessment ratios: Cook County residential 10% / commercial 25% of market value; rest of Illinois 33 1/3%. Cook County reassesses triennially by township; pooled 2021-25, multifamily (7+ units) won reductions in 60.7% of reassessment-year appeals vs 13.9% in off years. Cook BOR commercial evidence list includes rent roll, lease agreements and 3 years of IRS Schedule E forms. Ownwell full-service state.
What wins in Illinois
Homes are argued on comparable sales and uniformity. Income property is argued on the income approach — rent roll, expenses, and a supported cap rate. The packet builds the argument that matches your property type, with your evidence organised as exhibits.
Segments: Residential · Multifamily · Commercial · Pricing
Largest counties in Illinois
Cook County · DuPage County · Lake County · Will County · Kane County · McHenry County · Winnebago County · Madison County · St. Clair County · Champaign County · Sangamon County · Peoria County · McLean County · Kendall County · Rock Island County · Tazewell County · LaSalle County · Kankakee County · DeKalb County · Macon County · Vermilion County · Williamson County · Adams County · Whiteside County
General information from public sources, not legal advice. Software, not representation. FairAppealPacket is not a law firm, a licensed appraiser, or a licensed property-tax consultant. We do not file, appear, or negotiate for you. You review, sign, and file your own appeal. No result is guaranteed.
See what your deadline and your numbers say
The check is free and uses your own numbers — no score invented from data we do not have. If your worksheet shows no indicated saving, we will tell you not to buy a packet.