What is the property tax appeal deadline in Wisconsin?

Open Book period (varies by municipality, typically April–June). Typical deadline month: May. Always verify the current deadline with your local assessor as dates can change.

What is the success rate for property tax appeals in Wisconsin?

An estimated 44% of property tax appeals in Wisconsin result in a reduction. This is based on Lincoln Institute research and state-reported data. Success rates are highest when appeals are supported by recent comparable sales.

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Wisconsin Property Tax Appeal Guide

Q: How do I appeal my property tax in Wisconsin?

In Wisconsin, file your appeal with the Board of Review. The typical deadline is Open Book period (varies by municipality, typically April–June). The filing fee is $0. Start by contacting your assessor informally, then follow the formal process if unresolved.

How to challenge your property tax assessment in Wisconsin — deadlines, process, and a savings calculator.

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Compiled byPlainpropertytax Editorial, Property Tax Editorial Team

May

Typical Deadline

Filing Fee

~44%

Est. Success Rate

Board of Review

Appeal Body

What This Data Tells Us About Appeals in Wisconsin

In Wisconsin, property tax appeals are filed with the Board of Review. The typical window is Open Book period (varies by municipality, typically April–June), with the deadline most commonly falling in May. Filing fees reported for this state are $0, and Lincoln Institute research plus state-reported data suggest roughly 44% of appeals result in some reduction when supported by comparable sales or documented errors.

Wisconsin assesses at full market value. You must attend the Open Book before appealing to the Board of Review, this is a statutory requirement. Appeals are driven by the gap between a parcel's assessed value and its actual market value — the calculator below turns that gap into an annualized dollar figure at your effective tax rate. The strongest evidence is three to five arms-length comparable sales from the past six to twelve months, plus documentation of any factual errors in the assessor's record (square footage, bedroom count, finished-basement status).

This guide is for informational purposes only and is not legal or tax advice. Deadlines, filing fees, success rates, and procedures vary by county within Wisconsin and can change year to year. Always verify the current rules with your local assessor's office — or a licensed attorney or tax professional — before filing. Source: Wisconsin Department of Revenue.

Appeal Deadline

Open Book period (varies by municipality, typically April–June)

Appeal Body: Board of Review

Step-by-Step Appeal Process

1
Review your assessment from the local assessor
2
Meet with the assessor during the Open Book period to discuss your assessment
3
File an appeal with the local Board of Review during its session
4
Attend the Board hearing and present your evidence
5
If denied, appeal to the Circuit Court within 90 days

Wisconsin-Specific Notes

Wisconsin assesses at full market value. You must attend the Open Book before appealing to the Board of Review, this is a statutory requirement.

Source: Wisconsin Department of Revenue

Assessment Savings Calculator

Estimate whether an appeal is financially worthwhile and your potential annual savings.

Current Assessed Value ($)

Estimated Market Value ($)

Effective Tax Rate (%)

Find your rate on your tax bill or the county website

Frequently Asked Questions

How do I appeal my property tax in Wisconsin?

File with the Board of Review. Open Book period (varies by municipality, typically April–June). Start by requesting an informal review with your assessor, then follow the formal process outlined above if the issue is not resolved.

What is the Wisconsin property tax appeal deadline?

Open Book period (varies by municipality, typically April–June). The typical deadline month is May. Always confirm the exact date with your local assessor's office, as deadlines can change year to year.

Do I need an attorney to appeal property taxes in Wisconsin?

No. Most homeowners successfully appeal without legal representation, especially at the initial administrative level. The process is designed to be accessible to ordinary homeowners.

What evidence is most effective for property tax appeals in Wisconsin?

Recent sales of comparable homes (3–5 "comps" from the last 6–12 months) that sold for less than your assessed value are the strongest evidence. An independent appraisal ($400–$800) is the gold standard. Property data errors (wrong square footage, extra rooms) are also persuasive.

Disclaimer: This guide is for informational purposes only and does not constitute legal or tax advice. Appeal deadlines, procedures, filing fees, and success rates vary by county within Wisconsin and change over time. Always verify current rules with your local assessor's office or a licensed attorney before filing. Success rates are estimates based on Lincoln Institute of Land Policy research and state-reported data — individual results vary.

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