Assessment Process

The assessment process in Wisconsin is regulated by the WI Department of Revenue (DOR). State law requires that assessors are certified by the DOR. Certification involves an exam that tests their knowledge of appraisal and assessment law and administration. Assessors are also required to follow an assessment manual which is issued by the DOR.

 

The 2026 assessment cycle is complete. In-person exterior and interior property reviews for the 2027 assessment year will begin in September of 2026. Assessment notices will be sent to all property owners in 2027 even if your assessment doesn’t change. 

Wisconsin has an annual assessment. This means that each year’s assessment is a new assessment. The assessor may change your assessment because of building permits or sales activity even if the assessor did not inspect your property.

Under state law (sec 70.05(5), Wis. Stats.), each municipality must assess major classes of property within 10 percent of full value in the same year, at least once within a five-year period. If a City does not comply after six years, the State will conduct a supervised assessment. The reports of compliance for all municipalities, by county, can be found here: https://www.revenue.wi.gov/Pages/EQU/mclass-home.aspx.

More information is available in the 2026 Guide for Property Owners on this page.

Frequently Asked Questions

What is assessed value?

Assessed Value is the value the city assessor places on each real property parcel and on each individual’s taxable personal property. Under state law, all non-agricultural assessments must be based on the property’s market value as of January 1 of the assessment year. State law recognizes that every municipality cannot be assessed exactly at market value each year. The law requires that each municipality is within ten percent of market value once every five years. Assessed values are used to distribute the City’s taxes among the individual property owners.

Category: Assessor
What do tax assessors do?

City tax assessors are state certified individuals whose duties are to discover, list, and value all taxable real property in the municipality in a uniform and equitable manner. In performing these duties, assessors are required to follow state law, case law, and the Wisconsin Property Assessment Manual. The property values determined by the assessor are then used to calculate the amount of property taxes to be paid. The assessor is not involved in the collection of property taxes. 

Category: Assessor
How is assessed value determined?

The law requires that property be valued from actual view or from the best information that can be practicably obtained. This information may include the sale of the property, review of new construction, review of improvements, or physical inspection of the property.

Category: Assessor
How will I know the amount of my assessment?

Whenever an assessor changes the assessment of any property the owner must be notified. (Failure to receive a notice does not affect the validity of the changed assessment.) The notice must be in writing and mailed at least 15 days (30 days in revaluation years) prior to the Board of Review meeting. 

Beginning April 10, property owners will be able to view their assessed values at apraz.com/search.asp. If you would like to know your assessed value before April 1, you may contact Associated Appraisal Consultants directly by emailing info@apraz.com or calling 920-749-1995.

Category: Assessor
What if I don't agree with my assessment?

Once the fieldwork by Associated Appraisal Consultants is complete, you can call Associated Appraisal Consultants at 920-749-1995 to speak directly with the assessor about your assessment, if you do not agree with it.

In order to provide property owners with more flexibility in being able to speak with the assessor, Associated Appraisal Consultants will offer an extended period of Open Book via phone. The assessor will be available for calls to discuss property values from the time assessment notices are received until 48 hours before the Board of Review convenes.  For those property owners who prefer to have an appointment, there will be a daily schedule available on the Associated Appraisal Consultants website to sign up for a scheduled time.

The assessor will explain how your assessment was prepared, review the property record for your property and explain what factors were considered in determining a value for your property. 

 

Category: Assessor
What if, after the informal Open Book process, I still disagree with the assessment?

You must file an Objection Form with the municipal clerk at least 48 hours prior to the meeting of the Board of Review. You will then appear before the Board of Review for a hearing where you will present your case regarding the assessed value of your property.

Category: Assessor
What evidence do I need to present to the Board of Review?

The best evidence of value is the recent sales price of your property. The next best evidence is the arm's-length sales of reasonably comparable properties.  These are properties similar to yours in location, age, style, condition, and other features that affect market value, such as the number of bathrooms, bedrooms, and size of the garage. More information can be found in the Guide for Property Owners located at the bottom of this page.

Category: Assessor
When will the new property assessment go into effect?

The new assessments are effective January 1 and will appear on the tax bill you receive in December of the current year.

Category: Assessor
What is a property assessment revaluation?

A revaluation is performed by the city assessor when the property records are outdated or inaccurate, assessment uniformity is poor, a full revaluation hasn’t been performed for ten years, or reassessment is required under state law (sec. 70.75, Wis. Stats.).

Revaluation types:

•  Full revaluation –  implies that present records are outdated or confidence in their accuracy is lost. It will entail on-site interior and exterior inspections, measuring, listing and photographing of all buildings.

•  Exterior revaluation –   is sometimes sought when there is not total confidence in the property record cards, but questions can be verified without interior inspection

•  Interim market update –  implies that there is confidence in the property record system and all that is needed is professionally performed valuation updating

The City is required by the State to undergo a revaluation whenever the equalized value of a class of property (residential or commercial) falls below 90% for several consecutive years. The City of Platteville underwent a Full Revaluation in 2018 and an Interim Market Update in 2022 and 2024, due to the significant changes in property values regionally and state-wide. When the City undergoes a revaluation, it does not mean the City will collect more taxes because of the revaluation, but the distribution of those taxes may change based on the valuation of individual properties. 

Category: Assessor

Supporting Documents

PDF icon 2026 Guide to Property Owners (1 MB)
PDF icon Full Revaluation Presentation (2 MB)
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