DuPage County, IL

DuPage County property tax appeal 2027: deadline, forms and how to file

Scan from recent salesFacts not yet verified by a person — confirm on your notice

To appeal a DuPage County assessment, file with the DuPage County Board of Review online at dupageilsmartfile.tylerhost.net; in Illinois the deadline is 30 days after the township assessment list is published (Cook County uses township filing windows). Confirm the exact date on your notice or with the assessor; we add each county's 2027 date here when it is published.

Owners whose assessments changed other than by the county equalization factor are mailed a change-of-assessment notice; assessments are then published by township in a local newspaper. For 2026 the notices and publications ran from late August to early October by township (for example Wayne published 8/28/2026, Lisle 10/9/2026). The 2027 schedule is not yet published.

Data as of 20 Oct 2026 · DuPage County Board of Review

Your home

Check your own assessment

Free. We compare the value on your notice with recent sales of similar homes nearby and tell you whether an appeal is worth filing. Have your assessment notice and tax bill handy.

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How to file

How to file in DuPage County

Step 1
File the appeal
Online at dupageilsmartfile.tylerhost.net with the account number on your notice. State the grounds the county recognises.
Step 2 · before the hearing
Prepare and submit your evidence
Overvaluation must be shown by a preponderance of the evidence; a uniformity (equity) claim needs clear and convincing evidence. The strongest evidence is a recent arm’s-length purchase of your home, or an appraisal as of January 1. Otherwise use at least three comparable sales, or for equity at least three similar nearby homes with their assessments and property record cards, in a grid. Bring a photo of your home and its property record card.
Step 3
Meet, then hear
An informal review with Township assessor or Supervisor of Assessments comes first; if you decline the offer, the DuPage County Board of Review hears the case. Most reductions happen at the first step.

Before you file: how to read your notice · evidence that works · informal vs formal hearing · when not to appeal

Forms

Forms accepted by DuPage County Board of Review, 2027
Form	Number	Use	Format
Residential Comparison Grid (Fill-In & Print)	—	Supplemental comparable-property grid the Board asks appellants to use for residential evidence	PDF
Attorney Authorization	—	Authorization form for an attorney filing on the owner's behalf	PDF
Residential Appeal (Property Tax Appeal Board)	PTAB-1A	Only after the Board of Review decides: the state appeal, due 30 days after the board’s written notice. Can also be filed online through PTAB eFile.	Fillable PDF

Levels

Appeal levels

Where a DuPage County protest can go, in order
Level	Who hears it	Deadline	Cost
Informal review	Township assessor or Supervisor of Assessments	Before the Board of Review deadline	Free
Board of Review	DuPage County Board of Review	30 days after the assessment list is published	Free
Property Tax Appeal Board	Illinois Property Tax Appeal Board (state)	30 days after the Board of Review’s written decision	No filing fee
Court	Circuit court (administrative review), or a tax objection in DuPage County circuit court	35 days after the PTAB decision; tax objections follow the tax-bill penalty date	Court costs

Evidence

What evidence the board accepts

Overvaluation must be shown by a preponderance of the evidence; a uniformity (equity) claim needs clear and convincing evidence. The strongest evidence is a recent arm’s-length purchase of your home, or an appraisal as of January 1. Otherwise use at least three comparable sales, or for equity at least three similar nearby homes with their assessments and property record cards, in a grid. Bring a photo of your home and its property record card.

Questions

DuPage County questions

When is the DuPage County appeal deadline for 2027?

No 2027 date is published yet. The board’s rule: Appeals must be e-filed no later than 30 days after legal publication of the township's assessments; the Supervisor of Assessments posts the publication date and final complaint date for each township on its Assessment Status page (for 2026 the final dates ranged from 9/28/2026 to 11/9/2026). Appeals filed outside the 30-day window are rejected. Faxed or e-mailed appeals are not accepted.

How do I appeal my assessment in DuPage County?

File online at dupageilsmartfile.tylerhost.net. Online filing is the method the DuPage County Board of Review publishes.

Should I talk to the assessor first?

Yes. The township assessor or the DuPage County Supervisor of Assessments can fix record errors informally. Still file with the DuPage County Board of Review by the deadline: a board complaint is required before any state appeal.

What evidence works best?

A recent arm’s-length purchase of your home or an appraisal as of January 1. Otherwise, at least three comparable sales, or three similar nearby homes with lower assessments, with property record cards and photos.

How do I contact the DuPage County Supervisor of Assessments?

Mail: DuPage County Board of Review, 421 North County Farm Road, Wheaton, IL 60187. Phone: 630-407-5888. Hours and walk-in details: dupagecounty.gov.

What if the Board of Review says no?

Appeal to the Illinois Property Tax Appeal Board within 30 days of the board’s written decision. There is no fee, and you can file online through PTAB eFile. A lowered value on an owner-occupied home carries over for the rest of the assessment period.

Your home

Check whether yours is over-assessed

Nearby

Nearby counties

Kane County · Cook County · Kendall County · Lake County · Will County · DeKalb County · McHenry County

Sources