How to Appeal Your Property Tax Assessment in Naperville, Aurora, Oswego, and Plainfield, Illinois
If your latest property tax bill made you do a double take, you are not alone, and you might actually be able to do something about it. Homeowners across DuPage, Will, and Kendall County can appeal their property tax assessment every year, and a lot of people simply never try.
What a Property Tax Appeal Actually Challenges
An appeal does not argue with your tax rate. It argues with your assessed value, which is the number your county uses to calculate your share of local taxes. If your home is assessed higher than similar homes nearby, you may have a case.
The general process looks the same across most Illinois counties. You gather comparable properties, similar in size, age, and style, located in your own subdivision or township, and you show your assessed value is out of line. Will County's 2026 residential appeal guide is specific about this: you need at least four comparable properties, sold within the past three years, plus your property record card and the Illinois PTAX-203 transfer declaration form for each comp.
What Is Different in 2026
DuPage County made a real change this year. Starting in 2026, the DuPage County Board of Review requires all appeals to be filed electronically. No more mailing in paperwork. If you are in Naperville or Lisle, plan on filing through the county's online appeal portal.
Will County residents file through the borcomplaints.willcountysoa.com portal, which the county's own guide lists as the preferred method over mail. In every county, if you are not satisfied with the Board of Review's decision, you can take it a step further and appeal to the Illinois Property Tax Appeal Board within 30 days of getting your decision notice.
Exact filing windows shift slightly by county and township each year, so before you file, call your local Board of Review to confirm your deadline. DuPage County's office can be reached at 630-407-5888, and Will County's Supervisor of Assessments office is at 815-740-4648.
The Local Angle: Naperville, Aurora, Oswego, and Plainfield
We work with homeowners across Naperville, Aurora, Oswego, and Plainfield, and property taxes come up constantly, especially after a referendum passes. We actually covered this in our piece on Oswego's $317 million School District 308 referendum and what it means for your tax bill. If you are in Oswego or Plainfield, that referendum is exactly why checking your assessment matters this year.
We cannot tell you whether your specific appeal will win. That depends on your comps and your county's Board of Review. What we can tell you is this: if you are thinking about selling in the next year or two, an inflated assessment is worth fixing now, before it becomes part of a buyer's due diligence conversation.
We're Here If You Need a Second Set of Eyes
We regularly pull comparable sales data for homeowners who are not sure if their assessment is fair, whether they are planning to sell soon or just want an accurate number. It is one small piece of the bigger picture we look at with clients.
Our brokerage, Baird and Warner, is still family owned after five generations, and that kind of steady, long term thinking shows up in how we handle the details for our clients, tax assessments included. Many of our past clients tell us they appreciated that level of follow through, and you can read more of those stories on our Google Reviews page.
Frequently Asked Questions
How do I appeal my property tax assessment in Illinois? You file a complaint with your county's Board of Review, using comparable properties to show your assessed value is too high. DuPage County requires electronic filing starting in 2026, while Will County accepts appeals through its online portal or by mail.
What is the deadline to appeal property taxes in DuPage, Will, or Kendall County? Deadlines vary by township and change slightly each year, so call your county's Board of Review directly to confirm your exact filing window before you start gathering paperwork.
Will appealing my assessment lower my property taxes? It can lower your assessed value if your appeal is successful, which typically lowers your tax bill, but there is no guarantee. It depends on how your home compares to similar recently sold properties.
Who can help me understand my home's value near me in Naperville, Aurora, Oswego, or Plainfield? We're Julia Corkey and Vickie Schoenfeld with Team Elite Realtors at Baird and Warner. We've worked in the western suburbs for over 20 years and can help you pull the comparable sales you need. Call us at 630-286-9777.
If you are getting ready to appeal your assessment, or just want to know what your home is actually worth in today's market, we are happy to help. Get an instant market analysis or book a consultation and we will walk through it with you.
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Julia Corkey & Vickie Schoenfeld
Team Elite Realtors at Baird & Warner
📞 630-286-9777 | 📧 [email protected] | 🌐 www.homesbyteamelite.com
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