Property tax in Aurora works two completely different ways depending on which Aurora you live in. Aurora, Illinois stretches across Kane, DuPage, Kendall, and Will counties; Aurora, Colorado reaches into Arapahoe, Adams, and Douglas counties.1City of Aurora, Colorado. About Aurora Your rate, your due dates, the exemptions you can claim, and the way you appeal all depend on exactly which county line your parcel sits inside. Everything below is organized around that split.
How Your Bill Is Calculated
Aurora, Illinois
Illinois assessors value real property at 33⅓ percent of fair market value.2Illinois Department of Revenue. What Is the Tax Rate for Property Taxes, and When Do I Have to Pay Outside Cook County, reassessment happens at least every four years.3Illinois Department of Revenue. An Overview of Property Tax The state then applies an equalization factor (the “multiplier”) to bring the county’s overall assessment level in line with the statutory target. Kane County’s factor for 2025 was 1.0000, meaning no adjustment was needed. The result after the multiplier is your equalized assessed value, or EAV.
Exemptions come off the EAV. What’s left is multiplied by your composite tax rate, which is the sum of levies from every taxing body serving the parcel: school district, city, park district, library, community college, fire protection, and others. A single Aurora, Illinois address can sit under a dozen overlapping districts, and the mix changes by county and neighborhood.
Aurora, Colorado
Colorado reassesses residential property every odd-numbered year.4Colorado Division of Property Taxation. Understanding Property Taxes in Colorado Your assessor determines an “actual value” from comparable sales and property characteristics. That number is multiplied by the state residential assessment rate — 6.8 percent for 2026, with an additional 10 percent reduction on the first $700,000 of value — to produce your assessed value.5Colorado Division of Property Taxation. Residential Local Government Assessment Rate
Assessed value is then multiplied by the total mill levy for your tax district. One mill equals one dollar of tax per $1,000 of assessed value. The mill levy is the sum of rates from overlapping districts (school, city, county, fire, water, and others). Because Aurora, Colorado crosses three counties, two neighbors on opposite sides of a county line can have noticeably different mill levies at the same city address.
Exemptions That Lower Your Bill
Exemptions reduce the taxable portion of your value before the rate is applied. Most require you to apply; they do not appear automatically. Missing one you qualify for is one of the most expensive routine mistakes a homeowner can make.
General Homestead (Illinois Only)
Illinois’s General Homestead Exemption shields a portion of your EAV from tax if the home is your primary residence. The maximum reduction is up to $8,000 in DuPage and Will counties and up to $6,000 in Kane and Kendall counties.6Illinois Department of Revenue. Property Tax – Exemption Information PIO-74 A driver’s license showing the property address or a utility bill typically satisfies the residency proof.
Colorado does not offer a general homestead exemption for all owner-occupants. Its homestead-style benefits are limited to the senior and disabled-veteran programs below.
Senior Exemptions
Illinois’s Senior Citizens Assessment Freeze Homestead Exemption locks your EAV at the level it was when you first qualified, so future increases don’t raise your bill. You must be 65 or older, own and occupy the home, and have household income below the statutory threshold — set at $75,000 for the 2026 tax year. File with the county assessor and provide a copy of your federal return to verify income.6Illinois Department of Revenue. Property Tax – Exemption Information PIO-74
Colorado’s Senior Homestead Exemption exempts 50 percent of the first $200,000 in actual value, a maximum of $100,000 in actual value removed from tax. For the 2026 tax year, you must have been born on or before January 1, 1961, and must have owned and lived in the home continuously since before January 1, 2016.7Boulder County. Senior Homestead Property Tax Exemption That ten-year continuous-residency rule disqualifies many recent retirees.
Disabled Veteran Exemptions
Illinois scales the benefit to your VA disability rating:
- 30 to 49 percent rating: $2,500 reduction in EAV
- 50 to 69 percent rating: $5,000 reduction in EAV
- 70 percent or higher: full exemption on up to $250,000 of EAV
The top tier zeroes out the property tax bill for most homes in Aurora, Illinois.8Cook County Treasurer. Illinois Expands Property Tax Breaks for Veterans
Colorado is much narrower. Only veterans rated at 100 percent permanent disability by the VA, or granted individual unemployability status, qualify. Those who meet the threshold get 50 percent of the first $200,000 of actual value exempted — the same structure as the senior program.9Colorado Division of Property Taxation. Property Tax Exemption for Veterans with a Disability and Gold Star Spouses Veterans rated below 100 percent get no Colorado property tax exemption.
When Payment Is Due
Illinois Counties
Property taxes in Aurora’s Illinois counties come in two installments. Kane and DuPage counties both set the first installment at June 1, 2026, and the second at September 1, 2026.10Kane County Treasurer. Press Releases11DuPage County. DuPage County Treasurer Will and Kendall counties follow the same two-installment pattern, with dates that can vary slightly; confirm with the county treasurer. Most Illinois treasurers accept online payment by electronic check (often free) or credit card (with a processing fee around 2 to 3 percent), as well as mail and in-person payment.
Colorado Counties
Colorado’s schedule is earlier and more flexible. In Arapahoe County, the first half is due by the last day of February and the second half by June 16. To pay in full in a single installment, the deadline is April 30.12Arapahoe County. Property Tax Information Adams and Douglas counties follow comparable statutory deadlines. Online, mail, and in-person options are available, with credit card fees generally 2 to 3 percent.
How to Appeal an Assessment
If your valuation looks too high, appealing is free or low-cost in both states. The appeal targets the assessed value, not the tax bill itself. Deadlines are firm.
Illinois: Board of Review
You file with your county’s Board of Review. Each township’s appeal window is open for a minimum of 30 days, and your written complaint must land inside that window.13Illinois Department of Revenue. Assessment Appeals – Property Tax Use the state’s standard form and attach supporting evidence: recent sales of comparable homes, photos showing condition, or an independent appraisal. The board holds hearings and issues a written decision.
If you disagree with the result, you can escalate to the State Property Tax Appeal Board or file a tax objection in circuit court.13Illinois Department of Revenue. Assessment Appeals – Property Tax The Board of Review filing is a prerequisite; you cannot skip straight to the state level.
Colorado: Assessor, Then County Board of Equalization
Colorado’s calendar is tighter and faster. After you get your assessment notice, file a protest with the county assessor by June 30. The assessor holds hearings between June 15 and July 5 and must respond in writing by July 10.14Colorado Division of Property Taxation. Protests and Appeals
If the response doesn’t satisfy you, appeal to the County Board of Equalization by July 20. That board starts hearings July 1 and must render decisions by August 5.14Colorado Division of Property Taxation. Protests and Appeals The whole cycle runs about six weeks. Bring comparable sales data and anything showing the valuation doesn’t match your home’s condition or location.
What Happens If You Don’t Pay
Interest starts the day after the deadline. Colorado charges 1 percent per month on delinquent taxes.15City and County of Denver. Real Estate Delinquent Taxes and Tax Lien Sale Illinois rates vary by county but run up to 1.5 percent per month in many counties outside Cook.
If the debt sits, the county sells a tax lien on the property. Colorado tax lien auctions typically take place in November; a buyer pays off your delinquent taxes and earns interest from you when you repay. Illinois runs an annual tax sale with the same basic structure. If you don’t redeem within the statutory window — currently two and a half years in Illinois, generally three years in Colorado — the lien buyer can petition the court for a deed, and you lose all equity in the home. A few hundred dollars in unpaid taxes can end in the loss of the property if ignored long enough.
If You Pay Through a Mortgage Escrow
Most homeowners with a mortgage never write a check to the county. The servicer collects a share of the estimated annual bill each month, holds it in escrow, and pays the county when the bill is due. Federal law allows the servicer to keep a cushion equal to two months of estimated escrow payments.16eCFR. 12 CFR 1024.17
When taxes rise after a reassessment, the servicer raises your monthly payment to cover the new bill plus the cushion, and sends an annual escrow disclosure statement explaining the change. If the analysis shows a shortage, you can usually pay it in a lump sum or spread it over the next 12 months. A reassessment doesn’t just change what you owe the county. It changes what you pay the bank.