The City of Janesville Assessor’s Office is working on the next citywide property revaluation. The last full revaluation was completed in 2023, and current estimates show that the average property assessment will increase by about 25%.

All property owners will receive a Notice of Assessment Change by May 2027. This notice will show your previous assessment and your new proposed assessment for 2027.

To prepare for the revaluation, the Assessor’s Office is collecting market information through December 2026. State guidelines say that assessed values shall fall between 90% and 110% of actual sale prices. Janesville’s current ratio, based on 2025 sales, is 83.04%, which shows that assessments need to be updated.

Revaluations do not raise or lower the total amount of taxes collected. Instead, they make sure each property is taxed fairly based on its market value.

• If your assessment goes up more than the average, your taxes may increase.
• If your assessment goes up less than the average, your taxes may go down.
• If your assessment changes about the same as the average, your taxes should stay roughly the same.

If you have questions, please contact the Assessor’s Office at (608) 755-3045. 

Watch: 2027 Citywide Revaluation Presentation

Review: 2027 Citywide Revaluation Slideshow

Property Assessment Inspections Underway

City assessment staff have begun conducting residential property inspections, which will continue through February 2027.

During this period, assessment staff will collect information about residential properties. The information gathered in 2026 will be used to help determine property values for the 2027 assessment roll. Appraisers do not set property values during inspections; they only gather data. With permission, they will inspect both the inside and outside of a home.

Assessment staff may visit a property for several reasons, including:

• Follow‑up inspections from previous years
• New construction
• Building permits that may affect property value
• Recent property sales
• Follow‑up from an Open Book meeting
• Routine periodic review
• A property owner’s request for an assessment review

Staff will first send a letter asking property owners to schedule an inspection. Letters are usually mailed twice a month. If there is no response, staff will visit the property. If no one is home, they will leave a green notice on the front door. This notice asks the owner to call and make an appointment so staff can verify both interior and exterior information. If no appointment is made, staff will estimate the 2027 assessment using the best information available.

Assessment staff will wear a City ID badge and drive a white City sedan. If you are unsure of a staff member’s identity, you can call the Assessor’s Office at (608) 755‑3045 to confirm. You can also call this number with general questions about the assessment process.

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