How to Appeal Property Taxes in Will County, Illinois (2026 Guide)

The 2026 Will County residential assessment appeal deadline is Monday, September 14, 2026. File with the Will County Board of Review through the online complaint portal at borcomplaints.willcountysoa.com when it opens, or submit a paper complaint to the Board of Review at 302 N. Chicago Street, 2nd Floor, Joliet, IL 60432.

Do not wait for the tax bill. In Will County, the appeal is about your 2026 assessed value—not whether your taxes feel high—and the county says emailed or faxed complaint forms are not accepted.

How assessments work in Will County

Will County is under township assessment. Your local township assessor estimates the fair market value of your home using property characteristics, neighborhood sales, and a sales-ratio study. For 2026, the county’s FAQ says assessments are based on sales from 2023, 2024, and 2025. Residential assessed value is generally 33.33% of fair market value before equalization and exemptions.

A simple way to read your notice: if the assessor’s fair market value is $450,000, the assessed value is roughly $150,000 before any equalization factor. Your tax bill later uses your equalized assessed value, subtracts exemptions, and multiplies by your tax-code rate. The Treasurer explains that rates vary by tax-code area because schools, municipalities, parks, fire districts, libraries, and other taxing bodies set levies.

That distinction matters. The Board of Review can correct the assessment if the evidence shows your property is overvalued, inequitably assessed, or has incorrect physical data. It cannot lower your taxes simply because the rate rose, a school levy increased, or your bill is unaffordable.

The 2026 filing window is tied to publication of the assessment list. The Board’s rules state that completed complaints must be filed within 30 calendar days after publication of the current assessment list. For 2026, the official portal states that new complaint submissions are accepted August 12, 2026 through September 14, 2026.

Whether you should appeal

Appeal if you can prove one of these Will County-specific points:

1. Overvaluation: The assessor’s market value is higher than what comparable homes support. Will County’s 2026 rules say overvaluation evidence should use sale data from 2023, 2024, and 2025.
2. Equity: Similar homes in your neighborhood or subdivision are assessed lower than yours.
3. Incorrect property data: Your township property record card has the wrong square footage, finished basement, bathroom count, garage size, condition, or other physical feature.

Start with your township assessor before filing. The Board of Review recommends that step, and it can sometimes fix a clear data error without a formal hearing. But the rules are explicit: talking with the assessor does not extend the filing deadline.

Your strongest residential evidence is local and boring: three or more comparable sales in the same subdivision or nearby area, similar in age, size, style, construction, quality, and condition. Will County’s rules say residential complainants must include required evidence at filing, including dated photos and the local township assessor’s property record card. Do not rely on Zillow estimates alone.

One local reality: Will County publishes Board of Review final decisions, but I did not find an official county summary giving a residential success rate or median reduction. Treat anyone quoting a countywide “average savings” number without a county source with caution.

Step-by-step how to file

1. Find your PIN and assessment. Use the Will County Supervisor of Assessments property search if you do not know your Property Index Number. Confirm the owner name, address, township, assessed value, and property characteristics.

2. Get the right form. Most homeowners use the 2026 Residential Complaint Form. Official forms are listed on the Supervisor of Assessments Forms page and the Board of Review Complaint Downloads page. Other official forms include the Affidavit of Hearing Waiver, Board of Review Complaint Disclosure Form for trust property, Signature Form, Board of Review Complaint Withdrawal Form, and Verification of Authority to Represent Owner(s) of Real Property Form if an attorney files for you. Beginning in 2026, attorney authority must be the current notarized Will County form.

3. Build your evidence packet before you file. For a typical residential overvaluation complaint, include:

• the completed and signed 2026 Residential Complaint Form;
• your requested assessed value;
• a written explanation of why the assessment is wrong;
• at least three comparable sales, preferably in the same subdivision and township;
• front and back photos of your home, plus front photos of comparable properties, camera-dated and taken in 2026;
• the front and back of the township assessor’s property record card, not just a Supervisor of Assessments printout;
• recent purchase documents if you bought the property on or after June 30, 2026.

If you file no evidence, Will County’s rules say you receive a 5-minute No Evidence Hearing, and a hearing waiver will not be accepted.

4. Choose a filing method. The preferred method is the Board of Review online complaint portal. The portal requires you to register, complete the editable PDF complaint form, print/sign/scan it, and upload it with evidence. Paper filings go to:

Will County Board of Review
Will County Office Building
302 N. Chicago Street, 2nd Floor
Joliet, IL 60432
Phone: 815-740-4707

The county’s rules say faxed and emailed complaint forms will not be accepted. The official materials I reviewed do not list a filing fee for a residential Board of Review complaint; your costs are usually copies, photos, sales records, or an optional appraisal.

5. File by September 14, 2026. Submit the complete complaint and evidence together. Do not assume you can supplement later; the rules generally require evidence at filing.

What happens after

The appeal authority is the Will County Board of Review. The Board determines the assessed value of parcels that are the subject of complaints and acts as an equalizing authority.

If you do not waive an oral hearing, you will receive notice through the portal or by mail. Hearings are normally held at the Supervisor of Assessments Office, 302 N. Chicago Street, 2nd Floor, Joliet. Visitors must pass through building security, so arrive at least 15 minutes early. Will County says hearings cannot be rescheduled if you are late, and the 2026 rules say the Board does not conduct telephone or virtual hearings.

A residential hearing is short: most are scheduled in 15-minute intervals. You or your attorney presents testimony and answers Board questions. The township assessor may also present testimony. Then each side may make closing or rebuttal remarks. A single Board member may act as hearing officer, but at least two members must concur before a decision is final.

For many homeowners, the better option is the Affidavit of Hearing Waiver. If you sign it and indicate that no oral hearing is required, the Board will decide the case from the written evidence. This waiver is available for residential and farm property, not commercial or industrial property.

Decision timing is not instant. The rules say official findings are posted and mailed upon completion of the Board of Review cycle, and no written decisions are released before that. As a reference point, the county announced 2025 final decisions for January 28, 2026, with a PTAB appeal deadline of February 27, 2026. If you lose at the county level, review your written decision promptly because state appeal deadlines are short.

Local tips

Check exemptions before you appeal. An assessment appeal lowers value; exemptions lower taxable EAV. Will County lists several homeowner exemptions worth checking: General Homestead, Senior Citizens Homestead, Senior Citizens Assessment Freeze, Disabled Persons, Disabled Veterans Standard Homestead, Returning Veterans, and Homestead Improvement. The General Homestead Exemption and Senior Citizens Homestead Exemption each have a maximum EAV reduction of $8,000. For 2026, the Senior Citizens Assessment Freeze income limit is $75,000 or less.

Use your actual tax-code rate for savings. Will County tax rates vary. The Treasurer’s calculation page gives an example tax rate of 8.3629, meaning $50,000 of net EAV produces a $4,181.45 tax bill.

Here is a realistic appeal example using that rate:

• Assessor’s market value: $420,000
• Assessed value at one-third: $140,000
• General Homestead Exemption: $8,000
• Net taxable EAV before appeal: $132,000
• Your comparable sales support market value: $390,000
• Revised assessed value at one-third: $130,000
• Net taxable EAV after appeal: $122,000
• EAV reduction: $10,000
• Estimated tax savings at 8.3629: $10,000 × 0.083629 = $836.29

That is an estimate, not a guarantee. Your real savings depend on your parcel’s tax-code rate, equalization, exemptions, and the final assessment accepted by the Board.

Do not file a weak “my taxes are too high” appeal. In Will County, the winning file is specific: the township property card is wrong, comparable sales prove a lower fair cash value, or comparable assessments show inequity. Put those facts in the original packet and meet the September 14 deadline.