Property Assessment Process

Real property must be revalued every odd numbered year in order to establish accurate values for all property located within the county. The actual value of real property is based on its value as of the appraisal date, which is the June 30th of the year prior to the reappraisal year. Residential property must be valued using only the market approach to value. In this approach, the value of the subject property is based on an analysis of comparable sales to predict the price properties would have sold for on the Appraisal date.

2-Year Reappraisal Study Period

Assessment Calendar

2024 Assessment Rates

The assessment rates for certain classes of property are listed below: 

Residential 6.765% (Changes to the residential rate will be determined by the Colorado Legislature)

Multi-family 6.80%

Agricultural 26.4% *

Renewable Energy including Personal Property for Renewable Energy 26.4% 

All other classes shall remain at 29%, unless stated in the law.

  • Note: All other Ag (Agricultural businesses) remain at 29%

Data Collection

This is the first step in the assessment process. Any information on ownership, location, use, sales, building measurements, construction type and costs, land characteristics and rental income are obtained from real property deeds and declarations, subdivision maps, building permits, and local building contractors. Other primary sources are declarations filed by owners of taxable personal property and appraisers who conduct on-site inspections to gather land and building characteristics.

The Assessor’s office values your property for ad valorem property taxation purposes. Mass appraisal is a process that allows for valuation of a universe of properties on June 30th of every even year in order to produce uniform, fair, and equitable values.

The sales are grouped by property types (single family, condos, townhomes) and regional location (economic/neighborhood areas).  Value models are developed for each property type and their respective economic/neighborhood area. Economic/neighborhood areas have direct and immediate effects on value.                                                                                                
Neighborhood is defined by natural, man-made, or political boundaries and is established by commonalty, based on land use, types and age of buildings or population, the desire for homogeneity, or similar factors.
Economic area is a grouping of neighborhoods that have similar economic forces or geographic location. 

In mass appraisal statistical and regression analyses of sales data, trends and patterns are used in creating base rates and adjustment factors which are applied to the universe of properties to estimate each property’s value.

Notice of Valuation

The Assessor is required to send a Notice of Valuation to property owners by May 1 of each reappraisal year (odd numbered years) for real property. During intervening (even numbered years), only those real properties with a change in characteristics from the previous year receive a Notice of Valuation. If you feel the value the Assessor has placed on your property is incorrect, you may wish to file an appeal. 
You have the right to appeal your property value or its classification each year. Procedures for appealing your assessment are provided on this website, including deadlines for filing your appeal.

Certification to Taxing Authorities and Tax Warrant

In August of each year, the Assessor certifies the total assessed value of all properties located within the boundaries of each taxing authority. Assessed values are calculated by multiplying the actual value by the appropriate assessment rate. The residential assessment percentage is subject to change by the Colorado Legislature each odd numbered year. The assessment rate is currently 6.765% on residential property and on multi-family. These figures are used by the taxing authorities to determine their mill levies.

A mill levy is a tax rate that is applied to the assessed value of a property. The mill levy - which is sometimes refereed to simply as a levy - is multiplied times the assessed value of a property to determine the amount of taxes due. 1 mill = .001 as a multiplier.

For example: 87.925 mill levy x $15,000 assessed valuation = $1,318.87 property tax.


Each year county commissioners, city councils, school boards, and special districts (known as “taxing authorities”) determine the revenue needed and allowed under the law to provide services for the following year. They calculate a tax rate based on the revenue needed from property tax and the total assessed value of real and personal property located within the entity’s boundaries. The authorities determine their individual mill levies, which are then submitted to the Board of County Commissioners for review by December 15th. The mill levies are approved by the Board of County Commissioners and certified to the Assessor by December 22nd. Upon the receipt of the certified mill levies from the commissioners, the Assessor enters the mill levies, extends the calculations against the individual assessed values and forwards the resulting tax warrant to the Treasurer by January 10th for collection.

Additional Resources