City skyline over Lake Monona.
Assessor's Office

Open Book & Assessment Appeals

Assessment Notices

2026 assessments will be mailed May 1 and available on our website May 2.

Open Book: Correct assessment record with appraiser

During the Open Book period, you can review your assessment record. If any details are incorrect, we will correct the error and adjust your assessment. These might include:

  • Change in the number of rooms
  • Building permit that was not completed on January 1, 2026

During this period, our staff can also explain the methods and information we use to assess your property.

The 2026 Open Book Period to correct assessment records is May 4 – May 8, 2026. To correct an assessment record, please contact us at:

If your property details are correct but you disagree with the assessed value of your property, you will need to file an objection with the Board of Assessors by 4:30pm on May 15, 2026.

Board of Assessors: File an objection to assessed value

If you believe the market value of your property is different from the assessed value, you can file an objection to share information and data with the appraisal staff.

  1. File an Objection

    To review your property with the Board of Assessors, you must file an objection form by Friday, May 15, 2026 at 4:30pm. To file an objection, please contact us at:

    If you miss the May 15 filing deadline, you will need to request a waiver from the Board of Review.

  2. Board of Assessors

    The Board of Assessors will review and process all objections (Wis. Stat. § 70.075). Assessments in the City are established through mass appraisal. During the objection process, the Board will appraise your property individually, and review all adjustments to arrive at market value.

    The Board of Assessors meets weekly throughout the summer and early fall. The 2026 Board of Assessors meetings begin in June.

  3. Board of Review

    If you disagree with the determination of the Board of Assessors, the final municipal review of assessments is the Board of Review. The Board of Review is a quasi-judicial body comprised of appointed City residents who hear the cases and make final determinations on value.

    The Board of Review meets as needed throughout mid-summer and early fall.

Additional Filing Requirements for Commercial Properties

If you are filing an objection for a commercial or multi-unit property, you will also need to include the following with your objection form, if they apply to your property:

  • Income and expense information: Required for all commercial properties (Wis. Stat. § 70.47(7)(af))
    • Pro forma statement
    • Operating statements from the prior two years
    • Leases for retail, office or warehouse space
    • IRS Form 8825 or IRS Schedule E
    • A copy of your rent roll as of January 1 of the current year, or leases with all names redacted (Rental Property)
  • Gross rent statement: Required for all 2-7 unit properties.
  • Agent authorization form: Required if an agent is representing the property owner.

More Information

Watch a brief and informative video about the assessment process here: Video: Property Assessment in Madison.

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