DuPage County, Illinois — Property Tax Appeal Guide

Last reviewed: April 2026 · Tax year covered: 2025 (billed 2026), 2026 (billed 2027) Sources: DuPage County Supervisor of Assessments, DuPage County Board of Review Rules, Illinois Department of Revenue PIO-74

Quick facts (DuPage County, 2026)

If you've just received a Notice of Assessment Change, this page walks you through how DuPage's system works, when and how to appeal, what evidence the Board of Review actually considers, and which exemptions you may be missing.

How DuPage County assessments actually work

Illinois assesses residential property at 33⅓% of fair market value (the "assessment ratio") under state law. That means if the assessor believes your home's market value is $450,000, your assessed value should be approximately $150,000. Your tax bill is then calculated on the assessed value, not the market value.

The math:

Tax bill = (Assessed Value − Exemptions) × Equalization Factor × Local Tax Rate

There are two places this can go wrong, and both are appealable:

1. Market value overstatement. The assessor's implied market value is higher than what comparable homes are actually selling for. This is the most common appeal basis.
2. Lack of uniformity. Other homes in your neighborhood with similar characteristics are assessed at lower values. This is a different argument with different evidence rules — see the Board of Review section below.

DuPage uses a 9-township system: each township has its own elected assessor who produces the initial valuation. The County Supervisor of Assessments then applies an equalization factor to bring townships into rough alignment. Your appeal starts at the township level.

Should you consider appealing?

This page is general orientation, not advice on your specific case. That said, common red flags that suggest looking closer at your assessment:

• Your assessed value (×3) implies a market value noticeably above recent nearby sales of similar homes

• You purchased the home recently for less than the assessor's implied market value, with no major improvements since

• The assessor's record contains factual errors about your home — wrong square footage, wrong bedroom/bathroom count, wrong year built, demolished features still listed, lot size off

• Your assessment increased substantially more than your neighbors' between cycles

• A nearby comparable home has a lower assessed value despite being similar in size, age, and condition

DuPage publishes a free property records lookup where you can verify your home's record and compare it to neighbors. Each township assessor also publishes its own searchable database — see the table below.

What does NOT typically work as an appeal basis: the tax bill being "too high" in absolute terms, taxes increasing year over year (when caused by the local rate, not the assessment), or general arguments about fairness without supporting evidence.

DuPage County township assessors (all 9)

You'll deal directly with your township assessor for an informal review and for the formal appeal filing. Find your township first — DuPage County provides a township locator and the county property lookup will also tell you.

Contact data verified April 2026 against the DuPage Township Assessor Directory. Names and offices change — confirm before submitting documents.

The DuPage three-tier appeal process

Tier 1 — Township Assessor (informal review)

Before filing a formal appeal, contact your township assessor's office. Most townships will conduct an informal review where they look at your record and your comparables. Many cases are resolved at this stage without needing a formal Board of Review filing — particularly when the issue is a factual data error in the property record.

This is the lowest-cost step. If the assessor agrees with your evidence, they can adjust the assessment directly.

Tier 2 — DuPage County Board of Review (formal appeal)

If the informal review doesn't resolve it, you file a formal appeal with the County Board of Review.

Critical timing rule: appeals must be filed within 30 days after your township's assessment roll is published in the local newspaper. There is not a single county-wide deadline — each township has its own publication date, and each township's 30-day window starts from that date. Check the DuPage Assessment Status page for current dates.

For reference, the 2025 assessment year publication began October 16, 2025 in the lead townships, opening the 30-day appeal window. The 2026 cycle will follow a similar fall timeline.

How to file:

• Complete the appeal form (forms page) with supporting evidence

• Submit in duplicate to the Clerk of the Board

• Faxed and emailed appeals are not accepted under Rule 8 of the Board's procedures

• All required signatures must be original (owner, taxpayer, or licensed attorney)

• Corporate appellants must be represented by an Illinois-licensed attorney

The Board reviews evidence after the filing window closes and mails written decisions the following March. Hearings are conducted at the Board's discretion — most residential appeals are decided on the written record without an in-person hearing.

Tier 3 — Illinois PTAB or Circuit Court (state escalation)

If the Board of Review denies your appeal or grants insufficient relief, you have 30 days from the decision notice to escalate to either:

• Illinois Property Tax Appeal Board (PTAB) — administrative, no attorney required, decisions can take 1-3 years
• Circuit Court — judicial, attorney typically required, generally faster but more expensive

You cannot pursue both paths simultaneously for the same tax year.

What evidence the DuPage Board of Review will and won't accept

This is where most DIY appeals fail in Illinois. The Board has formal evidence rules (Rules of the Board of Review) that govern what comparable sales are admissible, how recent they need to be, and what documentation must accompany them. Failure to meet these rules is, by their own Rule 1, "grounds for the dismissal of any assessment appeal."

For market-value appeals (Rule 9, residential)

The Board considers comparable sales within 12 months of the assessment date (January 1 of the assessment year). They expect:

• Three (but not more than five) comparable properties
• Each comp's sale price, sale date, descriptive data, and a photograph

• Comps similar in size, construction, quality, age, style, and condition to the subject property

• Comps located in the same neighborhood or subdivision — and if they aren't, you must explain why

Acceptable comp documentation includes:

• Sales contract with closing statement and RESPA disclosures

• Multiple Listing Service (MLS) listing sheet

• Contractor's affidavit (for new construction)

• Appraisal by an Illinois State Licensed or Certified appraiser, dated January 1 of the assessment year

For the subject property itself

• Recent sale of the subject property within 12 months of the assessment date — generally the strongest single piece of evidence, particularly if the price was below the assessor's implied market value
• A current appraisal by an IL-licensed/certified appraiser

For uniformity appeals (different argument)

If your case is "my home is assessed higher than similar homes in my neighborhood," you submit:

• Three to five comparable assessed properties (not sales) with similar size, construction, age, style
• A summary table showing each comp's assessed value vs your own

Note: a uniformity appeal is a different theory than a market-value appeal. Pick the strongest one and frame your evidence around it — mixing both sometimes weakens your case.

Common reasons appeals are dismissed in DuPage

• Fewer than 3 comps, or more than 5

• Comps outside the 12-month window

• Comps in a substantially different neighborhood without explanation

• Missing required photographs or documentation

• Filed by fax or email

• Missing original signatures

• Corporate appellant without attorney representation

• Missing the 30-day filing window

Exemptions available to DuPage homeowners (Illinois statewide)

Beyond appealing the assessment itself, Illinois offers several exemptions that reduce your taxable assessed value. DuPage as a county contiguous to Cook County qualifies for the higher tier of the General Homestead Exemption.

Multiple exemptions can stack for the same home. A senior homeowner in DuPage with income under $75,000 can hold the GHE ($8,000), Senior Homestead ($5,000), and Senior Freeze simultaneously.

Apply through your township assessor's office. Most exemptions auto-renew once granted, but the Senior Freeze requires annual income recertification.

What actually wins and loses at the PTAB — analysis of recent DuPage decisions

If you escalate beyond the County Board of Review to the Illinois Property Tax Appeal Board (PTAB), your case becomes part of a public record. We pulled and read 8 final administrative decisions issued for DuPage County residential properties (tax years 2022-2024, decided through October 2025) to identify what evidence patterns succeed and which fail.

Outcome distribution (8-decision sample)

This is a small hand-pulled sample, not a comprehensive statistical study. PTAB issues hundreds of DuPage decisions per year. But the patterns in this sample are consistent with PTAB's published rules and are echoed in the agency's own annual synopsis publications.

The single biggest reason DuPage appeals lose at PTAB: comparable-sales recency

In 5 of 5 "No Change" decisions in our sample, PTAB explicitly downweighted comparable sales that were too far from the January 1 assessment date of the tax year being appealed. From the published decisions:

"The Board gives less weight to the appellant's comparable #3 ... due to their sale dates occurring greater than 15 months prior to the January 1, 2022 assessment date at issue." — Golewale (Milton Twp), Docket 22-03618

"The Board gives less weight to ... appellant comparable #2 and board of review comparables #1 and #2 [which] sold in 2020 or 2021, less proximate to the January 1, 2023 assessment date than other properties in the record." — Dang (Downers Grove Twp, pro se), Docket 23-04997

"The Board gives less weight to ... the sale for board of review comparable #4 which occurred in 2021, less proximate in time to the subject's January 1, 2023 assessment date at issue." — Stifflear Trustee (Downers Grove Twp), Docket 23-05295

Practical takeaway: comps must be from within ~12 months of the January 1 assessment date to receive full weight. Sales 15+ months out are routinely discounted. This is stricter than the BoR's "within 12 months" rule.

The second reason: comparables that aren't actually comparable

PTAB explicitly weighs differences in:

• Dwelling size (square footage of living area)

• Age / year built — a 39-year-old subject with 25-year-old comps gets adjustments

• Design (one-story vs two-story, frame vs brick)

• Basement — finished vs unfinished is a major weight factor

• Lot size — significantly larger lots disqualify comps

• Bathroom count, fireplace count, garage size

Multiple losing decisions in our sample lost weight because appellant comparables "lack[ed] finished basement area, which is a feature of the subject" or were "significantly smaller than the subject dwelling."

The third pattern: the BoR usually outguns the appellant on evidence

In 4 of 5 losing decisions, PTAB found "the best evidence of market value" to be the Board of Review's comparables, not the appellant's. The BoR has access to the same MLS data and often submits more recent or more dimensionally similar properties. Appellants who arrived with 3 comps when the BoR submitted 4-5 better comps almost always lost.

Practical takeaway: if you're pursuing a market-value appeal in DuPage, plan to submit 5 strong comparables (not the rule-minimum 3), each within 12 months of the assessment date, and each closely matched on size/age/design/basement. Anticipate that the BoR will submit a counter-package of 4-5 comps that support the existing assessment.

Uniformity appeals are harder than market-value appeals

Section 1910.63(e) of PTAB's procedural rules sets two different burdens of proof:

• Market-value appeal: preponderance of the evidence (>50%)
• Uniformity (equity) appeal: clear and convincing evidence (higher standard)

In our sample, the uniformity case (Goworowski, Lisle Twp, Docket 24-04149) lost because 4 of 6 appellant comparables lacked the finished basement feature of the subject — meaning they couldn't be considered "similar in distinguishing characteristics" under the higher equity standard.

Practical takeaway: if you have both a market-value argument AND a uniformity argument, lead with market value. The lower burden of proof is meaningfully easier to meet.

The hidden lever: section 16-185 rollover for owner-occupied homes

The single winning decision in our sample, Prorok (Addison Twp, Docket 24-04911), did NOT win on evidence — they won on a legal mechanism most homeowners don't know exists.

Section 16-185 of the Illinois Property Tax Code states that when PTAB lowers the assessment of an owner-occupied residence, that reduced assessment carries forward for the remainder of the general assessment period (subject only to township equalization). This is the "PTAB rollover" rule.

The Proroks won their 2023 PTAB appeal (Docket 23-05153), which lowered their assessment to $163,320. For the 2024 tax year, DuPage tried to apply an 8.78% township equalization factor, raising their assessment to $195,804. The Proroks filed a follow-up PTAB appeal arguing the rollover applied. PTAB ruled in their favor: their 2023 reduced assessment should carry forward, with only the 1.0878 township equalization factor applied — final assessment $177,659 (not $195,804).

Practical takeaway: if you win a PTAB appeal on an owner-occupied DuPage home, you can file a follow-up "rollover" appeal each subsequent year of the same general assessment period (within 30 days of the prior decision) to lock in the reduction. Most homeowners and most service companies do not pursue this.

Pro se vs attorney-represented in the sample

Of 8 decisions in our sample, 6 appellants used attorneys (Brian Liston, Steven Kandelman, William Saranow, David Kieta, Jessica Hill-Magiera, Nora Devine — all Illinois property-tax-appeal specialists). 2 appellants were pro se. The single winning decision was pro se.

This is not a meaningful sample size, and the Prorok win was on a specific legal mechanism rather than evidence quality. But it is consistent with what PTAB's procedural rules and our broader reading suggest: DuPage residential PTAB appeals are won and lost on the quality of the comparable-sales package, not on attorney representation. Service companies (Ownwell, O'Connor, AppealDesk) and tax-appeal attorneys can certainly help with the work, but they do not have access to better evidence than a homeowner who pulls strong recent MLS-documented comps.

Source decisions analyzed

This synthesis is based on full-text reading of the following 8 decisions, all available as public PDFs from the Illinois PTAB website:

• Prorok (Addison Twp), 24-04911 — REDUCTION via 16-185 rollover

• Goworowski (Lisle Twp), 24-04149 — No change, uniformity

• Stifflear Trustee (Downers Grove Twp), 23-05295 — No change, market value

• Nolan (Downers Grove Twp), 23-05450 — No change, market value

• Dang pro se (Downers Grove Twp), 23-04997 — No change, market value

• Cederholm (Addison Twp), 23-05835 — Pre-hearing settlement

• Caifano (Addison Twp), 23-05245 — Pre-hearing settlement

• Golewale (Milton Twp), 22-03618 — No change, market value

PTAB also publishes annual Synopsis of Representative Cases (most recent: 2024 Synopsis) and annual reports with case counts and net-change-in-assessed-value data by county.

Recent DuPage context (FY 2026)

• DuPage County FY2026 budget: county tax rate held flat (NCTV17 coverage)

• 2025 assessment roll (billed in 2026): assessed values up 8.2%, average tax rate down 4.37%, net tax bill increase of 3.83%. The flat county portion is offset by school district and municipal levy growth, which drives the bill upward despite county-level discipline.

• Senior Freeze income cap raised to $75,000 for assessment year 2026 (up from previous $73,700), per recent Illinois legislation. Applies to seniors who own and occupy their primary residence.

• Next general reassessment year: 2027. Outside general reassessment years, individual properties can still be reassessed for new construction, demolition, or correction of errors.

Frequently asked questions

My assessor said my market value is X but I think it's lower. How do I prove it?

Pull 3-5 recent sales of similar homes within 12 months of the January 1 assessment date and within your neighborhood. Document each with sale price, date, descriptive data (sq ft, beds, baths, year built), and a photograph (MLS listing sheets satisfy this). If your home itself sold within the past 12 months for less than the assessor's implied market value, that single sale is often the strongest evidence.

Can I appeal if I think my property record has errors (wrong sq ft, wrong bed count)?

Yes — start at the township level. Many factual errors can be corrected by the township assessor without needing to escalate to the Board of Review. Bring documentation: original purchase listing, builder's specifications, photos.

Do I need a lawyer to appeal?

No, individual homeowners can file pro se. Corporate property owners must be represented by an Illinois-licensed attorney. Most residential homeowners DIY the township and Board of Review levels; attorneys become more common at PTAB or Circuit Court.

What about Ownwell, O'Connor, and the local "we'll handle your appeal" services?

These are property tax consulting firms that file the appeal on your behalf in exchange for a contingency fee — typically 25-35% of one year's tax savings. Some auto-enroll you for recurring annual service unless you opt out. They can be a reasonable choice if you don't have the time or comfort to gather evidence yourself, but the underlying work — finding comparable sales and submitting them with the appeal form — is something most homeowners can do directly. The Board of Review doesn't favor or disfavor appellants based on whether they're represented.

What's the actual success rate of DuPage appeals?

The Board of Review doesn't publish a unified success rate, and outcomes vary heavily by the strength of the evidence submitted. Anecdotally and from PTAB published decisions, well-documented appeals with 3+ qualifying comps and clear deviation from neighborhood values have meaningfully higher acceptance rates than appeals filed without comp evidence. The published BoR rules are explicit that procedural failures are grounds for dismissal regardless of merit — meeting the rules is a prerequisite.

My township's deadline already passed. Can I still appeal?

Not for that tax year through the Board of Review. You can file for the following assessment year when the next 30-day window opens after your township's roll publishes. If you missed the BoR window but the BoR has already issued a decision on a parallel filing, you have 30 days to appeal to PTAB.

Sources

• DuPage County Supervisor of Assessments — Appeal Process

• DuPage County Board of Review — Rules of the Board of Review

• DuPage County — Township Assessor Directory

• DuPage County — Assessment Status

• DuPage County — Forms and Documents

• DuPage County — Property Records Lookup

• Illinois Department of Revenue — Property Tax Exemption Information (PIO-74)

• Effingham County, IL — 2026 Senior Freeze Income Limit Increase to $75,000

• NCTV17 — DuPage County Board adopts FY2026 budget; tax rate flat

• Property tax rate and median data: propertytaxrates.org/counties/illinois/dupage-county/

This page is general guidance about how the DuPage County property tax appeal system works. It is not legal advice or a recommendation about whether to appeal your specific assessment. For case-specific advice, consult your township assessor or a licensed Illinois property tax consultant.