City assessor outlines 2025 revaluation process, explains how assessments affect tax bills

Wauwatosa City Assessor Sarah Tyrell told the Common Council the city will conduct a citywide property revaluation to align assessed values with current market conditions after the Department of Revenue flagged Wauwatosa assessments as out of compliance.

Tyrell described the revaluation process and timeline: the official valuation date is January 1; staff reviewed three years of arm's-length sales along with rents, capitalization rates and construction costs; the assessor's office will mail an informational postcard the week of July 7 and notices of assessment on July 18; the open-book period will run from July 18 to August 15 with extended office hours and a new online inquiry system to manage questions. After open book, the Board of Review will hear objections and, following hearings, the assessor will close the 2025 assessment roll.

Tyrell emphasized legal constraints: Wisconsin assessment practice is governed by Chapter 70 of the Wisconsin Statutes, the Wisconsin Property Assessment Manual and case law; assessments must average within 90 to 110 percent of market value. The Department of Revenue notified the city in 2021 that a revaluation was required; if the city fails to do the work by 2026, the state can hire a private firm and bill the city.

Tyrell said a common misconception is that an assessment change automatically means the same change in a tax bill; she explained that tax bills depend on the levies set by the city, county, school district and other taxing jurisdictions and that the assessor's role is one piece of the calculation. She said the assessor's office has five full-time staff and one part-time staff member and expects a heavy volume of inquiries during open-book; the office aims to respond within two to three business days.

Council members asked how assessments would shift across property classes; Tyrell said preliminary analysis shows average increases for residential and commercial classes are similar in Wauwatosa (so no large sectoral tax shift is expected), though within classes there will be differences (for example, apartment buildings have appreciated faster than some office properties). She encouraged councilmembers to refer constituents with specific questions to the assessor's online inquiry tool and said a tax-calculator tool is under development to illustrate hypothetical impacts without promising actual tax bills.

Why it matters: The revaluation will reset assessed values used to distribute property-tax levies; while a revaluation does not by itself set tax rates, many taxpayers perceive assessment increases as direct tax increases. The assessor's outreach plan and an online inquiry system are intended to reduce confusion and manage public contacts during the open-book period.

What happens next: Property owners will receive postcards in early July and notices on July 18; open-book and Board of Review procedures will follow and the assessor's office will respond to inquiries as staffing allows.