Property Valuation Process

Property Valuation Process

When Property Is Valued

The Assessor’s Office reappraises the value of real property (land and buildings) every odd-numbered year. The value is stated as of the appraisal date, which is June 30 of the year prior to the reappraisal year. The value determined by the Assessor is generally used for the intervening year as well.

The Mass Appraisal Process

The Assessor uses a mass appraisal process to predict property values. Multiplicative (logarithmic) multiple regression algorithms are derived from the variables in our database, as well as transformed variables that are created to improve the predictive capability of the model. This is done using the statistical software, SPSS.

The results are tested to ensure reasonable accuracy in property valuations.

The State of Colorado audits the outcomes for accuracy and fairness.

Physical Changes in Your Property

A property’s value may increase or decrease as a result of physical changes.

  • Improvements such as new rooms, a finished basement, or extensive remodeling and modernization will increase the value.
  • Paint, a new roof or repairs may not increase the value but will keep the home in good condition so the value does not drop.

Valuation of Residential Property

The Assessment Rate for Residential Property is 7.2% (signed into law June 5, 2017, changing from 7.96%)

The Market Approach

By law, residential properties must be valued by the market approach. This predicts the price a property would bring on the open market in a transaction between a willing, informed, and knowledgeable buyer and seller. It includes a review of comparable sales in the study period.

Time Trending is a technique for estimating the current market value of residential properties.

Valuation of Non-Residential Property

The Assessment Rate for Non-Residential Property is 29%.

Non-residential property is appraised using the cost approach, the income approach, and the market approach.

To appraise property using these methods, the Assessor and staff must review information gathered on individual properties, know what similar properties are selling for, and know what the replacement cost would be. Other factors that influence value may be location, availability of services, and rental rates.

The Market Approach

The market approach predicts the price a property would bring on the open market in a transaction between a willing and informed buyer and seller, when each party is knowledgeable concerning all the uses to which the property is adapted and for which it is capable of being used.

The Cost Approach

The cost approach estimates the material and labor costs to replace a building with a similar one. If the building is not new, the appraisal must consider its age and how much it has depreciated over time.

The Income Approach

The income approach is used for properties such as stores, office buildings, and warehouses. This method considers the landlord’s income and operating expenses and the financial return most people would expect from a given type of investment property.

Building Style Codes

These style codes describe buildings. They are either created by Assessor staff, or are based off of Marshall & Swift Estimator® Codes.

The Notice of Valuation

The Assessor sends a Notice of Valuation to property owners yearly that:

  • Describes the property you own
  • Gives the actual value for both the prior and current year
  • Is the form to be used in submitting an appeal to the Assessor

If your property’s value has not changed, your January tax bill is your notice of valuation for the coming year.

Study your Notice of Valuation carefully. Your property value will affect your tax payment due the following year.

If you believe your property’s assessed value is incorrect, you can inspect the Assessor’s records on your property and other properties.

Appealing a Valuation

When a property value is appealed, the Assessor reviews the value using a methodology that is similar to an appraisal. This allows the public and our appraisers to form a basis for discussion.

Tools include:

Taxpayers can decide if the comparable sales indicate a reasonable value for their property, and they can identify other sales that support a request for a value adjustment.

Appeals of real property values can be filed with the Assessor between May 1 and June 1.

Appeals of business personal property values can be filed with the Assessor between June 15 and July 30.

Deadlines for appeal are strictly enforced.

Contact Us


Phone: 303-441-3530
Fax: 303-441-4996

Business Personal Property
Phone: 303-441-3316
Fax: 303-441-1783

Mailing Address
Main: PO Box 471
Boulder, CO 80306-0471



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