How to appeal your property tax assessment in Illinois
In Illinois, if the value on your notice is too high, you can ask to have it lowered. You don't need a lawyer.
Checked against official sources: Oct 21, 2026
Can I still appeal?
It depends on where you live
Open now in some townships. Each township has its own window; for example, Cook County's Proviso Township closes October 27, 2026. Check your township's dates.
Illinois homeowners pay a median of $5,298 a year in property tax, an effective rate of 2.01%, the 2nd highest of the 51 states we cover.
Outside Cook County, a complaint must be filed with the county Board of Review within 30 days after your township's assessments are published in the newspaper. Dates are set by township each year. Example: Winnebago County 2026 - assessments published August 5-6, complaint deadline September 4-5. In Cook County, the Assessor opens a filing window for every township every year (not only in reassessment years); it usually runs about six weeks from the township's notice date (2026 example: Proviso Township notices 9/14/2026, last day 10/27/2026). The Cook County Board of Review then opens each township for at least 30 days.
Outside Cook County, owners get a mailed notice when their assessment changes, and changes are published in a local newspaper, usually in summer or fall. In Cook County, the Assessor mails a reassessment notice by township when that township is reassessed. Once you receive the tax bill it is generally too late to challenge that year's assessment.
Find your Illinois county
Where you file depends on your county. Pick yours for the office contacts, local tax figures and a step-by-step guide.
How much could you save?
Enter the market value on your assessment notice and what you think the home would really sell for. We estimate the yearly saving if the board agrees with you.
Some states cap how fast the taxable value of a home can rise (California, Florida, Michigan and Texas homesteads, for example). If your taxable value is already held below market value by a cap, a lower market value may not lower this year's bill.
How to appeal in Illinois, step by step
Understand your assessment
Outside Cook County, the township (or multi-township) assessor sets values and the county supervisor of assessments reviews and equalizes them. In Cook County (Chicago area), the elected Cook County Assessor sets all values. Outside Cook County, homes are assessed at 33 1/3% of fair market value. In Cook County, homes are assessed at 10% of market value. The county or state may then apply an equalization factor (multiplier). All property is reassessed every four years (a 'quadrennial' general assessment), with yearly adjustments in between. Cook County reassesses every three years on a rotating schedule: in 2026 the south and west suburbs, with the City of Chicago and north suburbs in other years.
Check the record and talk to the assessor
Outside Cook County, call or visit your township assessor first - errors (wrong square footage, wrong features) can often be fixed without a formal complaint, but this does not extend the Board of Review deadline. In Cook County, the first step is a free appeal to the Cook County Assessor, filed online during your township's window.
Gather your evidence
What works in Illinois:
- Recent sales of at least three similar homes nearby
- Equity comparables: at least three similar homes in the same neighborhood or subdivision
- Your own recent purchase price, with the closing statement, if it was an arm's-length sale
- A signed appraisal by a licensed appraiser
- Dated photos of your home
More detail
- Recent sales of at least three similar homes nearby, laid out on the county or PTAB grid sheet
- Equity comparables: at least three similar homes in the same neighborhood or subdivision with lower assessments (per-square-foot comparisons alone are not enough)
- Your own recent purchase price, with the closing statement, if it was an arm's-length sale
- A signed appraisal by a licensed appraiser - generally the strongest evidence; short opinion letters carry little weight
- Dated photos of your home (required by the Cook County Board of Review) and of comparables
File your appeal PTAB-1A PTAX-230
First level: County Board of Review (Cook County: Assessor, then Board of Review). File the county's assessment complaint form with the Board of Review (many counties accept online or email filing), attaching comparable-property grid sheets, photos, or an appraisal. The board holds a short hearing (in person, phone or video) and mails a written decision. In Cook County you can first appeal online to the Assessor, then file free with the Board of Review online, in person, or at a satellite office; pro se hearings are by phone. Cost: Usually no fee. The Cook County Board of Review says filing is free; most other counties do not charge a fee, but check your county's rules.
Prove your case at the hearing
Bring copies of your evidence for each board member. Keep to the value of your home, not the size of the bill.
More detail
The assessment is presumed correct. At PTAB, if you claim your home is valued above market value you must prove its value by a 'preponderance of the evidence' (more likely than not). If you claim it is assessed unfairly compared to neighbors (uniformity/equity), you must meet the higher 'clear and convincing' standard.
If you lose: Illinois Property Tax Appeal Board (PTAB) or circuit court tax objection
PTAB: within 30 days of the postmark date on the Board of Review's written decision. Circuit court (tax objection): only after paying the taxes, by the deadline set in the Property Tax Code. File the PTAB Residential Appeal form (PTAB-1A) online through the PTAB eFiling system or by mail to Springfield (no fax/email). Include the Board of Review decision and evidence for at least three comparables. There is no fee. Hearings are held by administrative law judges, usually in the county seat. You can instead pay the tax and file a tax objection complaint in circuit court, which generally requires a lawyer.
After you win
A Board of Review decision usually shows up on the next tax bill. If PTAB lowers the value after you already paid, the decision goes to the county treasurer, who must refund the overpaid taxes (timing varies by county). A PTAB reduction on an owner-occupied home carries forward for the rest of the general assessment period.
Official forms
PTAB-1A Residential Appeal (Property Tax Appeal Board)
PTAX-230 Board of Review Assessment Complaint (state form; this copy is hosted by Clark County, and many counties use their own version - get yours from your county)
Rules that are different in Illinois
- Deadlines are set by township and change every year - watch your notice or the county/Cook Assessor calendar closely; missing a window means waiting until next year
- Cook County homes are assessed at 10% of market value, everywhere else at 33 1/3% - compare your market value, not the raw assessed number
- Homestead carry-forward: a PTAB reduction on an owner-occupied home stays in effect for the rest of the general assessment period (subject to equalization), unless the home sells for a different price
- You must go through the Board of Review before PTAB or court
- The Board of Review can also raise assessments after notice
- Keep paying your tax bills on time - in Cook County the first installment is 55% of last year's bill regardless of the appeal
Is your home assessed higher than similar homes?
File a 'lack of uniformity' appeal: pick similar nearby homes (same class, size, age, style) and show their assessed value per square foot of building is lower than yours. Run the numbers with our unequal assessment calculator.
Most wins start with a mistake in the assessor's record of your home. Check it line by line.
Record card checklistExemptions that lower your bill without an appeal
An exemption is separate from an appeal: you apply once and it cuts your taxable value every year. Check you have every one you qualify for.
General Homestead Exemption
For owner-occupied homes: reduces equalized assessed value by up to $6,000 ($8,000 in counties next to Cook, $10,000 in Cook).
Senior Citizens Homestead Exemption
Owners 65+: an extra $5,000 off assessed value ($8,000 in Cook and contiguous counties).
Low-Income Senior Citizens Assessment Freeze
Owners 65+ with household income under the limit (rising to $75,000 for 2026) keep their assessed value frozen at a base year. Apply every year with the county.
Standard Homestead Exemption for Veterans with Disabilities
$2,500 off assessed value for 30-49% service-connected disability, $5,000 for 50-69%, and full exemption up to $250,000 for 70%+.
Do you need a lawyer or a tax consultant?
Homeowners can represent themselves at every level; hiring an attorney is optional. Property owned by an LLC, corporation or partnership must be represented by an Illinois-licensed attorney at PTAB and the Cook County Board of Review. Non-lawyers (appraisers, tax consultants) may testify and help but cannot question witnesses at PTAB. Many tax attorneys work for a share of the savings.
Free property tax appeal letter
Fill in your details and download a written appeal statement as a PDF. Most boards also require their own appeal form: file the form and attach this letter and your evidence to it.
RobinClaim is a free information site, not a law firm or appraiser. The letter is a template, not legal advice.
Illinois property tax appeal FAQ
What is the deadline to appeal property taxes in Illinois?
Outside Cook County, a complaint must be filed with the county Board of Review within 30 days after your township's assessments are published in the newspaper. Dates are set by township each year. Example: Winnebago County 2026 - assessments published August 5-6, complaint deadline September 4-5. In Cook County, the Assessor opens a filing window for every township every year (not only in reassessment years); it usually runs about six weeks from the township's notice date (2026 example: Proviso Township notices 9/14/2026, last day 10/27/2026). The Cook County Board of Review then opens each township for at least 30 days.
Where do I file a property tax appeal in Illinois?
First level of appeal in Illinois: County Board of Review (Cook County: Assessor, then Board of Review). File the county's assessment complaint form with the Board of Review (many counties accept online or email filing), attaching comparable-property grid sheets, photos, or an appraisal. The board holds a short hearing (in person, phone or video) and mails a written decision. In Cook County you can first appeal online to the Assessor, then file free with the Board of Review online, in person, or at a satellite office; pro se hearings are by phone.
How much does it cost to appeal in Illinois?
Usually no fee. The Cook County Board of Review says filing is free; most other counties do not charge a fee, but check your county's rules.
Can I talk to the assessor before filing?
Yes. Outside Cook County, call or visit your township assessor first - errors (wrong square footage, wrong features) can often be fixed without a formal complaint, but this does not extend the Board of Review deadline. In Cook County, the first step is a free appeal to the Cook County Assessor, filed online during your township's window.
What if the board turns me down?
Next level: Illinois Property Tax Appeal Board (PTAB) or circuit court tax objection. PTAB: within 30 days of the postmark date on the Board of Review's written decision. Circuit court (tax objection): only after paying the taxes, by the deadline set in the Property Tax Code. File the PTAB Residential Appeal form (PTAB-1A) online through the PTAB eFiling system or by mail to Springfield (no fax/email). Include the Board of Review decision and evidence for at least three comparables. There is no fee. Hearings are held by administrative law judges, usually in the county seat. You can instead pay the tax and file a tax objection complaint in circuit court, which generally requires a lawyer.
What happens if I win?
A Board of Review decision usually shows up on the next tax bill. If PTAB lowers the value after you already paid, the decision goes to the county treasurer, who must refund the overpaid taxes (timing varies by county). A PTAB reduction on an owner-occupied home carries forward for the rest of the general assessment period.
Sources
Checked Oct 21, 2026 against official Illinois sources. Local deadlines and fees can differ; confirm with your assessor or board.
- Illinois Department of Revenue - PIO-16, An Overview of Property Tax (R-10/23)
- Illinois Property Tax Appeal Board - Filing Your Appeal
- Illinois Property Tax Appeal Board - Practice and Procedures
- Illinois Property Tax Appeal Board - FAQ
- Cook County Board of Review - FAQ
- Cook County Assessor - Assessment Calendar and Deadlines
- Cook County - Property Tax Appeals overview
- Winnebago County Board of Review (2026 dates)
- Tax rate and median tax: U.S. Census Bureau, American Community Survey, 2020–2024 5-year estimates, tables B25103 (median real estate taxes paid, owner-occupied homes) and B25077 (median value, owner-occupied homes). The rate is the median tax divided by the median home value.