Rate Breakdown

Property taxes in Dekalb County are calculated by multiplying the assessed value (minus exemptions) by the total local millage rate.

How Property Tax Works in Dekalb County

In Dekalb County, the county treasurer’s office is responsible for calculating property taxes based on the assessed value of each parcel. The county board of assessors first determines the market value of a property on a set assessment date, usually the last day of March. That value is then multiplied by the county’s millage rate to determine the tax due. A millage rate is expressed in mills, where one mill equals one‑thousandth of a dollar. The county’s current millage rate is 20.00 mills, but additional school and special district millages may apply, bringing the total rate to roughly 35 mills. Property taxes are apportioned between the county, schools, and special districts according to these millage rates. The final tax bill lists each component, making it clear how much each entity receives.

Available Exemptions

Illinois provides several property‑tax exemptions that can reduce your liability. In Dekalb County the following are commonly claimed:

• Homestead Exemption – Reduces the assessed value of a primary residence by $50,000. To qualify, you must own and occupy the home.
• Senior Citizen Exemption – Available to homeowners 65 or older. The exemption amount is $45,000 for primary residences and can be combined with the homestead exemption.
• Disability Exemption – A permanent, total, and catastrophic disability, certified by the Illinois Department of Human Services, allows a $30,000 reduction in assessed value. If the homeowner also qualifies for the senior exemption, the two can be stacked.
• Veteran Exemptions – Veterans and Spouses of Honorably Discharged Veterans receive a $15,000 exemption, while disabled veterans earn up to $35,000. Eligibility is verified through the Illinois Department of Veterans’ Affairs.

Applications for each exemption must be filed with the county treasurer’s office by May 31 of the year in which the property will be tax‑assessed. Ongoing eligibility must be reported annually to maintain the benefit.

Payment Schedule & Deadlines

Dekalb County offers both a single‑payment option and a two‑installment plan:

• Single Payment – The full tax amount is due by May 30. Paying on time keeps the account in good standing.
• Installments – The first installment is due May 30 and includes 83% of the total tax. The second installment, for the remaining 17%, is due on September 30. Payments are accepted at the treasurer’s office, county branch offices, online, or by mail.

Late payments incur a 1% monthly interest rate, with penalties added to the principal. After 90 days past the due date, the treasurer may initiate a lien and, eventually, a tax sale if the debt remains unpaid. It is therefore prudent to pay by the first installment deadline or, if possible, in full.

Appealing Your Assessment

Disagreeing with the assessed value can lead to a reassessment, which may lower your tax bill. The appeals process in Dekalb County begins with a formal written request to the county assessor by July 31 of the assessment year. The request should include a brief statement of grounds and supporting evidence such as recent comparable sales, property condition reports, or appraisal certificates.

After the assessor reviews the submission, an initial decision is issued by August 15. If you are dissatisfied, you may file a formal appeal with the county’s Review Board by September 30. The Review Board will conduct a hearing, review evidence, and issue a binding decision. Appeals are issued in writing and must include any revised tax liability. Prompt action is essential; delays beyond the deadlines can forfeit the right to appeal.