Appeal guide · Illinois
How to appeal a commercial assessment in DuPage County
8 steps from the notice to the DuPage County Board of Review and beyond, with the forms, exchange deadlines and mistakes that decide commercial cases here.
Deadline
30 days after legal publication of the township's assessments (35 ILCS 200/16-55); each township's final filing date is posted on the Supervisor of Assessments' assessment status page, and appeals filed outside the window are rejected
Where to file
DuPage County Board of Review SmartFile e-filing system (electronic filing is mandatory for all appeals from 2026)
Statute
35 ILCS 200/16-55 (Board of Review complaints, counties under 3,000,000); 35 ILCS 200/16-160 (Property Tax Appeal Board)
The process, in order
The three-member Board of Review schedules hearings by mailed notice, usually by telephone, in 15- to 20-minute slots that generally cannot be rescheduled. A township deputy assessor attends with the property record card and the assessor's evidence. The Board may offer a stipulated value; an owner who signs a stipulation and waiver of appeal gives up the PTAB route. Written decisions are mailed after the county's hearings are complete, typically the following March.
Forms you will need
- +Board of Review assessment complaint (Commercial/Industrial), filed in SmartFile
- +Attorney authorization for the parcel
- +Income-producing property package (three years of operating statements, current leases and rent roll)
- +PTAB Commercial Appeal form
- 1
September and October
Track the township publication date
Watch the Supervisor of Assessments' assessment status page for the township's publication date and final filing date, and pull the property record card for the parcel.
- 2
As soon as the assessment publishes
Build the income package
Collect three years of operating statements, current leases and the rent roll, then normalize expenses and stabilize vacancy for the January 1 valuation.
- 3
Due no later than 10 days after the filing deadline
Order the appraisal if needed
Engage an Illinois licensed or certified appraiser for a January 1 value. All other evidence must be ready on the filing date.
- 4
Within 30 days of publication
File in SmartFile
File the commercial complaint electronically with attorney authorization where required, and upload all evidence at filing. Paper filings are not accepted.
- 5
Date and time set by the Board's mailed notice
Telephone hearing
Present within the 15- to 20-minute slot against the township deputy assessor's evidence. Rescheduling is generally not available.
- 6
Before signing
Decide on any stipulation
Compare the stipulated value with the indicated value at 33 1/3%; signing waives the PTAB appeal.
- 7
Typically the following March
Receive the written decision
The date of the written notice of decision starts the 30-day PTAB clock.
- 8
Within 30 days of the Board of Review's written decision
Appeal to PTAB
File the PTAB petition with the evidence; taxes must keep being paid while the appeal is pending, and a refund follows any reduction.
Mistakes that lose DuPage County appeals
- Using a county-wide date instead of the township's own publication date, and filing after the 30-day window closes.
- Filing the complaint and planning to upload operating statements later; only appraisals get a 10-day grace period.
- Ignoring a purchase of the subject within twelve months of January 1, which the Board treats as evidence of market value.
- Comparing the market value conclusion to the equalized tax bill value rather than the published assessment at 33 1/3%.
- Signing a stipulation without noticing that it waives the PTAB appeal.
Evidence rules
- 1.All evidence must be submitted at the time of filing in SmartFile; the only grace period is for appraisal reports, accepted no more than 10 calendar days after the filing deadline.
- 2.Income-producing property appeals should include three concurrent years of operating statements, current leases and rent rolls.
- 3.Appraisals must be prepared by an Illinois State Licensed or Certified appraiser and state value as of January 1 of the year under appeal.
- 4.The Board considers sales of the subject within twelve months of the assessment date as evidence of market value, so a recent purchase must be addressed head on.
- 5.Mailed, paper and postmarked filings are not accepted; late complaints are rejected.
Frequently asked
What is the commercial assessment level in DuPage County?
33 1/3% of fair cash value. DuPage has no classification system, so a $24 million industrial building should carry an assessed value of about $8 million before the state equalization factor.
How long do I have to file with the DuPage Board of Review?
30 days after legal publication of the township's assessments. Each township has its own publication date and final filing date, posted by the Supervisor of Assessments.
Can I mail a paper appeal?
No. From 2026 the Board of Review requires every appeal and all evidence to be filed electronically through SmartFile.
When can I go to PTAB?
Within 30 days of the Board of Review's written notice of decision, unless you signed a stipulation and waiver of appeal. Decisions are usually mailed the following March.
File a stronger DuPage County appeal this cycle.
ATALI ELECTRIC builds the income, sales and uniformity exhibits, fills the county forms and tracks every deadline.