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How Is Property Value Assessed?

You may have received a green or red tag on the door of your property from Associated Appraisal Consultants (AAC) or received an assessment notice in the mail. As a property owner and taxpayer, it’s important you understand the assessment process and Wisconsin’s property tax system. We will make every effort to provide helpful information and answer any questions you may have.

What to Expect During and After A Property Assessment

This short, animated video uses an analogy of a book to explain the property assessment process.

Thumbnail preview for the What to Expect When Your Property is Assessed video with play button

AAC is the largest mass appraisal firm in Wisconsin. Hundreds of municipalities hire us to perform assessment services every year on their behalf. Our website makes it easy to find answers to questions about the assessment process.

If you don’t see your question above, contact one of our knowledgeable and friendly staff Monday through Friday 8 a.m. – 4:30 p.m. We’re here to help!

You can help us by completing and submitting the following forms as appropriate:

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Real Estate Sale Questionnaire

If you recently purchased your home, please complete this form and email it to us. This helps us verify and analyze real estate sales in our assessment jurisdictions as required. 

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Property Record Questionnaire

This questionnaire helps us determine your property’s interior attributes, amenities, and condition when the municipality is not including interior inspection in the assessor’s scope of work. Please complete this form and provide any supporting documents. If changes were made to the property, please note the start date of the project. 

Why is my property being reassessed?

Assessors are required by law to update assessments and assessment records annually to account for physical changes to properties or changes to land use. State law also requires that each municipality must update assessed values to reflect changes in market conditions as often as possible to maintain uniform property taxation.  

If your municipality is updating all assessed values for market conditions, this process is called a “revaluation” or “interim market update.” If your property is being reassessed in a non-revaluation year, it is most likely due to new construction, remodeling, land use changes, or some other annual maintenance work. Assessors also review real estate sales on an annual basis.

What is mass appraisal or mass assessment?

Municipalities hire AAC to perform mass appraisal or mass assessment services on their behalf. We use standardized processes to collect property data and analyze local real estate sales. Mass appraisal is the process of appraising all properties in a municipality using a valuation model that is based on actual sales data, customized to fit local market conditions. The advantage of the mass appraisal process is that it produces uniform and consistent appraisal values, which helps to ensure fair and equitable tax distribution.

How is my property assessed?

If you received a green tag from AAC, that means your town or city hired us to perform a revaluation to update local property values to full market value. If you received a red tag from AAC, that means the assessor is following up on a sale, building permit, or other annual maintenance work in a non-revaluation year. 

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Annual maintenance assessments for new or changed properties

Wisconsin law requires that an assessor establish a new assessed value for any property with significant changes during the previous year. This includes new construction, any properties purchased or major improvements completed on an existing home or building, such as: 

  • Adding rooms, decks, patios or garages 
  • Replacing roofing or siding 
  • Doing interior remodeling 

While exact dates vary each year, maintenance assessments generally follow the timeline below.  

October – March

AAC inspects all properties that are new or have changed significantly in the past year.

March – April

Assessment notices are sent to property owners whose assessed value has changed.

April – June

Property owners can attend Open Book and Board of Review meetings to question assessments or make a formal assessment appeal.

Revaluation includes assessing all properties in a municipality 

A revaluation is a mass assessment to determine the current market value of all taxable property in a municipality. Revaluations are usually done every few years to help ensure fair and equitable tax distribution as required by state law. There are different types of revaluation services and some require an onsite inspection. Assessors will send a written notice to property owners if an inspection is desired during a revaluation year.  

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consumer.

While exact dates vary each year, revaluation assessments generally follow the timeline below.

October – July

If needed, AAC conducts onsite property inspections. As mentioned above, state law requires that assessors send a written notice to property owners if an interior inspection is desired for a revaluation.

July – August

Assessment notices are sent to all property owners even if a property’s value didn’t change.

August – September

Property owners can attend Open Book and Board of Review meetings to question assessments or make a formal assessment appeal.

Thumbnail preview of the Your Property's Valuation Story Infographic

Infographic: Your Property’s Valuation Story

This uses an analogy of a book to explain the property assessment process.

What’s the difference between assessed value vs appraised value?

The assessed value and appraised value of a property can be similar, but there are differences.  

Assessed Value

Purpose

Used to calculate property taxes

Factors Affecting Valuation

Property size, neighborhood, nearby amenities, improvements made in the past several years, historical property data, home inspection findings and data from all recent property sales in a community

Who Determines Value

Assessor on behalf of a municipality

About the Valuation

Represents full market value as of January 1, or may be less than market value in a non-revaluation year

Appraised Value

Purpose

Price someone would pay for the property if it sold today (also called “fair market value”)

Factors Affecting Valuation

Property size, neighborhood, nearby amenities, home improvements made in the past several years and recent sales of comparable properties

Who Determines Value

Appraiser as required by lenders for purchasing or refinancing a home

About the Valuation

Represents appraiser’s opinion of the full market value as of the date of appraisal

Purpose

Used to calculate property taxes

Price someone would pay for the property if it sold today (also called “fair market value”)

Factors Affecting Valuation

Property size, neighborhood, nearby amenities, improvements made in the past several years, historical property data, home inspection findings and data from all recent property sales in a community

Property size, neighborhood, nearby amenities, home improvements made in the past several years and recent sales of comparable properties

Who Determines Value

Assessor on behalf of a municipality

Appraiser as required by lenders for purchasing or refinancing a home

About the Valuation

Represents full market value as of January 1, or may be less than market value in a non-revaluation year

Represents appraiser’s opinion of the full market value as of the date of appraisal

What do assessors look at when determining the value of my property?

During the property assessment process, assessors will consider all factors that may affect the value of your property as if it was offered for sale on the open market. Some of the primary factors include the property’s size, construction type, age, amenities, location and condition. They also must consider fair market value (which is what a typical buyer would pay for the property), as well as historical property data, home inspection findings and market trends, like all recent comparable property sales in your community. 

Tip: Download these forms onto your computer, enter the requested information and save a filled copy.

How does assessed value impact my property taxes? How are property taxes calculated? 

Your property tax bill is based on the assessed value of your property, multiplied by the tax rate (also known as “mill rate”) for your taxation district. Property tax rates differ for property owners throughout the state due to various tax levies imposed by municipalities, counties, and school districts.  

An increase in assessed value doesn’t always mean an increase in property taxes. During a year when all assessed values in your municipality are being increased to full market value, the tax rates will generally decrease proportionally. What matters is whether your assessment (on a percentage basis) increased more than the municipality’s overall percentage increase. For example, if your assessed value increased 30% when the municipality’s overall increase was 20%, you would pay more in property taxes. But if your value increase less than 20%, your property taxes would likely go down. 

An assessor is a state-certified individual who has the responsibility to discover, list, and value all non-manufacturing taxable property in a municipality. It’s important to understand that assessors don’t determine tax rates or collect property taxes.  

To learn more, please see Section XI “Levy and Rates” in the Wisconsin Department of Revenue 2023 Guide for Property Owners or click the button below to watch a short video.

How do I request a review of my property?

If you think that your property assessment is over or under stated, we would be happy to review your value for the upcoming assessment year. You’ll need to complete and submit a form to start the review process.

What rights do I have as a property owner?

You have several rights as a property owner in Wisconsin, including receiving notice of an inspection during a revaluation year, the right to say “no” to an inspection and the right to appeal an assessment. AAC also takes safety seriously during all onsite property inspections.

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Precautions AAC takes to ensure your safety during an inspection

AAC sends a written notice to property owners if an inspection is desired by your municipality during a revaluation year.  

Our AAC logo is clearly shown on our vehicles, the apparel our team wears and their name tags to ensure our identification to you as professional, contracted assessors on behalf of your municipality. 

Team members will identify themselves as working on your municipality’s assessments when they arrive at your door. They will also carry written identification from your municipality.  

Your rights related to inspections

Assessors are required to send a written notice to property owners if an interior inspection is requested during a revaluation year. You aren’t required to allow assessors onto or into your property, but it’s typically to your advantage to ensure the best quality assessment. Allowing the assessor to view your property will ensure that the assessor is using current and complete information when making a valuation of your property. See the Property Owners – What rights do I have? page for more details.

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A middle-aged couple, with one holding tablet and one holding a book, sit on a light cough in a bright house.

Your rights to appeal assessments

As a property owner, you also have the right to appeal your assessment at Open Book and Board of Review meetings. You can find exact dates by searching for your municipality on the Wisconsin Department of Revenue site. See the Property Owners – What rights do I have? page for more details about your rights related to appeals.

AAC’s website can help you understand how your property value is assessed and more. If you still have questions or need help, contact one of our knowledgeable and friendly staff.