Property taxes in Illinois are assessed and collected at the local level — primarily by counties and municipalities — with rates varying significantly depending on where your home is located. The statewide average effective rate for 2025is 2.08%, meaning a homeowner with a $267,800 median-value home typically pays around $5,570 per year in property taxes. For a monthly perspective, that works out to roughly $464/month — a line item that should factor into every home purchase decision in Illinois.
Illinois uses a 33.3% assessment ratio for primary residential properties. This means the county assessor sets your home's taxable (assessed) value at 3333% of its market value. On a $400,000 home, for example, the taxable assessed value would be $133,320. Mill rates (the nominal tax rate per $1,000 of assessed value) are then applied to this lower figure.
Available Exemptions in Illinois
General Homestead Exemption: $10,000 reduction in equalized assessed value (EAV) — equivalent to ~$30,000 market value at 33.33% ratio. Cook County: $10,000 EAV reduction.
Senior Citizens Homestead Exemption: additional $5,000 off EAV (Cook County). Senior Freeze Exemption caps EAV increases for income-qualified seniors.
Returning veterans: $5,000 EAV reduction. Disabled veterans: $2,500–$250,000 EAV reduction depending on disability rating. 100% disabled: fully exempt.
What Makes Illinois's Property Tax System Unique
Illinois has the 2nd highest effective property tax rate in the US. The state relies heavily on property taxes to fund schools. Cook County (Chicago) uses a triennial reassessment cycle. The new "mansion tax" in Chicago affects high-value properties. Many residents pay a total of 2.5–3.5% effective rate depending on school district.
When Are Illinois Property Taxes Due?
Illinois property taxes are paid on a semi-annual (twice per year) basis. Due dates: June 1 and September 1 (Cook County). Varies for other counties.. Missing a due date typically results in penalty interest (often 1–2% per month) and eventually tax liens, so it is important to calendar these dates well in advance — especially if you have a mortgage and your lender handles property tax through escrow (in which case they pay on your behalf from your escrow account).
How to Appeal Your Property Tax Assessment in Illinois
If you believe your property has been over-assessed — which is surprisingly common, especially after rapid market changes — you have the right to appeal. Cook County: file with the Board of Review between July–December (depending on your township). Other counties: file with your local Board of Review within 30 days of assessment notice.
To build a strong appeal, gather comparable sales (homes similar in size, age, and condition that sold recently for less than your assessed value), photos documenting property defects, and any independent appraisals you have. Many homeowners who appeal see their assessments reduced — and some jurisdictions allow free informal hearings before a formal appeal is required.
Property Tax Rates by Major Illinois Cities
Within Illinois, effective property tax rates vary significantly by city and county. Here are the major areas and what to expect:
- Chicago— rates in this area may differ from the 2.08% statewide average. Use the calculator above with your specific assessed value for a more accurate estimate.
- Aurora— rates in this area may differ from the 2.08% statewide average. Use the calculator above with your specific assessed value for a more accurate estimate.
- Naperville— rates in this area may differ from the 2.08% statewide average. Use the calculator above with your specific assessed value for a more accurate estimate.
- Joliet— rates in this area may differ from the 2.08% statewide average. Use the calculator above with your specific assessed value for a more accurate estimate.
- Rockford— rates in this area may differ from the 2.08% statewide average. Use the calculator above with your specific assessed value for a more accurate estimate.
Note: County rates within Illinois can range from well below to well above the statewide average. Always verify the current mill rate with your county assessor's office.
Pro Tips for Illinois Property Owners
- Apply for every exemption you qualify for — many homeowners leave money on the table by not filing for the homestead or senior exemption. Applications are typically annual or one-time, and deadlines are firm.
- Review your assessment notice every year. If the county's estimate of your home's market value seems too high relative to what similar homes are actually selling for, appeal it. Even a 10% reduction on a $400,000 assessment saves $400–$700/year at typical Illinois rates.
- If you have a mortgage, confirm with your lender whether property taxes are paid via an escrow account. If so, ensure your escrow balance is adequate — under-funded escrow leads to an escrow shortage and a sudden increase in your monthly mortgage payment.
- Pay early if your state offers discounts. Some states (like Florida) give 1–4% discounts for early payment. On a $5,000 tax bill, a 4% early-payment discount saves $200 — for essentially zero work.
- Property taxes are generally deductible on your federal income tax return as part of the SALT deduction (state and local taxes), subject to the $10,000 cap introduced by the Tax Cuts and Jobs Act. For high-tax states, this cap is often a binding constraint.