Deadlines · Illinois counties outside Cook
DuPage County property tax appeal
You have 30 days after your township's assessment roll is published in the newspaper to file an appeal with the DuPage County Board of Review. Appeals filed outside that window are rejected.
DuPage County 2026 appeal deadlines
Official source: DuPage County Supervisor of Assessments
DuPage County township guides
How to file your DuPage County appeal
- 1
Check your township's publication date
Each DuPage township publishes its assessment roll in a local newspaper on its own schedule. Your 30-day appeal window runs from that publication date — the deadline for your township is on the county's assessment status page.
- 2
Talk to your township assessor first
The Board of Review strongly recommends reviewing your property record card with your township assessor before filing. Errors can often be corrected without an appeal — but the filing window is not extended while you talk.
- 3
Gather comparables
Evidence should include three or more comparable properties, preferably in your neighborhood. For a market-value appeal use recent sales; for a uniformity appeal use similar homes with similar assessments.
- 4
File online with SmartFile
Create an account on the county's SmartFile e-filing system and submit your appeal before your township's deadline. Residential and commercial instructions are on the county site.
- 5
Attend your hearing
The Board reviews your evidence and the assessor's evidence and mails a decision. If you disagree, you can appeal to the Illinois Property Tax Appeal Board (PTAB) within 30 days of the decision notice.
Good to know
- The first two digits of your parcel number identify your township.
- An appeal challenges your assessed value, not your tax bill amount.
File with the official DuPage County portal
Appeals are free to file with the county. Use the official DuPage SmartFile e-filing system — and if your home is in Cook County instead, we have a step-by-step guide and kit for that.