Rock Island County property tax bills are calculated by multiplying your property’s equalized assessed value (EAV) — one-third of fair market value — by the combined rates of every local taxing district that serves your address, then subtracting any exemptions you qualify for. The county splits each annual bill into four installments due between June and November, and missing a deadline triggers 1.5% monthly interest. For 2025 taxes payable in 2026, local taxing bodies are collecting roughly $335 million countywide, with about 61% going to schools and a community college.1Rock Island County, IL. Where Your Property Taxes Go
How Your Bill Is Calculated
Illinois law requires property to be assessed at 33⅓% of its fair cash value.2Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/9-145 – Statutory Level of Assessment Township assessors inspect properties and review recent sales to arrive at that number. A home that would sell for $180,000 has an assessment target of about $60,000.
Rock Island County runs on a four-year general assessment cycle. The current cycle began in 2023 and runs through 2026.3Rock Island County, Illinois. Assessment Office After local assessors finish, the Illinois Department of Revenue applies a state equalization factor to confirm the county’s overall assessment level matches the statutory one-third. For the 2025 assessment year the tentative factor is 1.0000, so no adjustment is being applied.
Each taxing district divides its levy by the total EAV within its boundaries to produce a tax rate. Your bill equals your EAV (after exemptions) multiplied by the combined rate of every district serving your parcel. Schools are the largest piece almost everywhere in the county, so if your bill feels high, that is where most of the money is going.
When Payments Are Due
The Treasurer mails bills by May 1 and splits each year’s taxes into four installments rather than two. For 2025 taxes payable in 2026, the due dates are:4Rock Island County, IL. Real Estate Property Tax Payments
- First installment: June 10, 2026
- Second installment: August 10, 2026
- Third installment: September 10, 2026
- Fourth installment: November 10, 2026
Installments must be paid in order. You cannot skip ahead to a later one while an earlier one remains unpaid.
You can pay online by credit or debit card, but the third-party processor charges a 2.45% convenience fee, or a flat $2.00 for transactions under $82.4Rock Island County, IL. Real Estate Property Tax Payments To avoid the fee, mail a check with your payment coupon, pay in person at the County Building with cash or certified funds, or use a participating local bank during collection season. Always include your parcel index number on anything you mail in.
What Happens If You Don’t Pay
Delinquent taxes accrue interest at 1.5% per month on the unpaid balance, with partial months counting as full months.5Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/21-15 – Delinquent Property Taxes Annualized, that is 18%. A modest bill can grow into a serious problem within a year.
If taxes remain unpaid after the final installment deadline, the Treasurer publishes a delinquency list in the local newspaper and asks the Circuit Court for a judgment and order of sale. Once the court approves, the unpaid liens are sold at the county’s annual tax sale. The winning bidder pays off your back taxes and receives a certificate of purchase. Your costs then jump: the county adds a $10 publication fee, $94 in processing fees, $160 in certificate-related costs, and whatever interest rate the buyer locked in at the sale, up to 18%.6Rock Island County, IL. Delinquent Taxes
You still have a redemption window to reclaim the property by paying everything owed plus accumulated interest and fees. For residential property, that window is at least two and a half years from the sale date, and the tax buyer can extend it up to three years.6Rock Island County, IL. Delinquent Taxes Miss the redemption deadline and the tax buyer can petition the Circuit Court for a tax deed. A judge reviews whether statutory requirements were met before ordering the County Clerk to issue it. At that point the property is gone.
Exemptions That Lower Your Bill
Several exemptions reduce your EAV before the tax rate is applied. You apply through the Rock Island County Assessment Office, and most require annual renewal.
General Homestead Exemption
If you own and occupy the property as your primary residence, you can claim up to $6,000 off your EAV each year.7Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/15-175 – General Homestead Exemption For most homes that have appreciated since 1977, the full $6,000 applies.
Senior Citizens Homestead Exemption
Homeowners 65 or older get an additional reduction of up to $5,000 off EAV.8Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/15-170 – Senior Citizens Homestead Exemption It stacks with the general homestead, so a qualifying senior can shave up to $11,000 off EAV combined. You need to show proof of age and residency, such as a driver’s license.
Senior Citizens Assessment Freeze
This freezes your EAV at the level in the year you first qualified. To qualify for the 2026 tax year, you must be 65 or older, own and occupy the home as your primary residence, and have total household income of $75,000 or less.9Illinois Department of Revenue. Property Tax Relief – Homestead Exemptions, PTELL, and Senior Citizens Real Estate Tax Deferral Program The income cap rises to $77,000 for 2027 and $79,000 for 2028 and beyond. The freeze locks your assessed value, not your tax rate, so your bill can still change if local levies rise.
Homestead Exemption for Persons with Disabilities
Homeowners with qualifying disabilities get a $2,000 annual EAV reduction.10Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/15-168 – Homestead Exemption for Persons with Disabilities Acceptable proof includes a Class 2 Illinois disability ID card, a Social Security Administration disability award letter, or a VA disability benefits letter. If none of those apply, you and a licensed physician can complete Form PTAX-343-A instead.11Illinois Department of Revenue. PTAX-343-A – Physicians Statement for the Homestead Exemption for Persons with Disabilities
Veterans with Disabilities Exemption
Illinois veterans with a service-connected disability certified by the VA get an exemption that scales with disability rating:12Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/15-169 – Standard Homestead Exemption for Veterans with Disabilities
- 30% to 49% disability: $2,500 EAV reduction
- 50% to 69% disability: $5,000 EAV reduction
- 70% or greater: the first $250,000 of EAV is fully exempt
Surviving spouses of veterans whose death was service-connected also qualify for the $250,000 exemption if they receive dependency and indemnity compensation and still occupy the home.
Natural Disaster Homestead Exemption
If your home is damaged by flood, fire, storm, or similar event, you may qualify for relief as long as you rebuild within two years and the new structure is no more than 110% of the original square footage.13Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 200/15-173 – Natural Disaster Homestead Exemption For flood damage, the property must sit in a jurisdiction that participates in the National Flood Insurance Program. Applications are due by July 1 of the taxable year and no later than the first taxable year after the home is rebuilt.
How to Appeal Your Assessment
If your assessment looks too high, start by requesting your property record card from the township assessor. These cards show the square footage, room count, and features used to value your home, and clerical errors are more common than most owners expect. An extra bathroom or a wrong lot size can inflate your assessment, and catching it may bring a correction without a formal hearing.
If the card is accurate but the number still looks wrong, the strongest evidence is comparable sales. Identify properties nearby with similar size, age, and condition that sold recently for less than your assessed market value. Record each one’s parcel number, sale date, and sale price. A recent professional appraisal and photos of deferred maintenance or damage also help. The Board of Review wants concrete numbers, not general arguments that your taxes feel too high.
The Rock Island County Board of Review opens its complaint session once assessment changes are published in the local newspaper. You have 30 calendar days from that publication date to file a written complaint.14Rock Island County, IL. Board of Review Office The assessment office mails notices of changes in early fall, but the legal clock starts with the newspaper publication, not the mailing. File your complaint in person or by mail with the Board of Review, including all supporting documentation.
The Board then schedules a hearing where you or a representative present the evidence. Members may ask about the property’s condition and review your comparables. A written decision follows. If you disagree with the outcome, you can appeal to the Illinois Property Tax Appeal Board (PTAB), a quasi-judicial body that reviews whether your assessment is correct based on the weight of the evidence.15Illinois Property Tax Appeal Board. State of Illinois Property Tax Appeal Board The PTAB appeal must be filed within 30 days of the Board of Review’s written decision, and faxed or emailed filings are not accepted.16Property Tax Appeal Board. Filing Your Appeal Submit all written evidence with your petition, because PTAB generally will not accept new documents at the hearing.