DeKalb County homeowners pay a median of $5,974 a year in property tax on a median home value of $243,600. Its effective tax rate (property taxes paid as a share of home values, per the Tax Foundation) is 2.24%, the 5th highest of 102 Illinois counties. Your home is valued by your township assessor and reviewed by the DeKalb County Supervisor of Assessments. To appeal, you file a complaint with the DeKalb County Board of Review.
Varies, some openOpen 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.
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.
Phone: 815-895-7120
County page: Assessment Office
Equalizes township values, publishes assessment changes and usually runs the Board of Review office. Call to find your township's filing window.
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.
Look up your home on the DeKalb County Supervisor of Assessments website and check square footage, bathrooms, condition and features. Mistakes are the easiest wins. Use our record card checklist.
File the county's assessment complaint form (many counties use PTAX-230 or their own form) with the DeKalb County Board of Review within 30 days after your township's assessments are published. Attach comparable sales or an appraisal. Many counties accept online or email filing.
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.
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.
Next step: 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.
The official appeal form is PTAX-230: Board of Review Assessment Complaint (form used by some downstate counties; many counties use their own form).
Open Form PTAX-230Enter 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.
Fill in your details and download a written appeal statement as a PDF or Word file. Most boards also require their own appeal form: file the form and attach this letter and your evidence to it.
Tax Appeal Map is a free information site, not a law firm or appraiser. The letter is a template, not legal advice.
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.
With the DeKalb County Board of Review, usually through the supervisor of assessments' office, within 30 days after your township's assessments are published.
Phone 815-895-7120. Website: dekalbcounty.org.
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.
Contact details change; call or check the office website before you visit.