Assessed Value

Iowa law requires the City or County Assessor to review all property in their jurisdiction in odd number years (2021) to be sure assessments are proper. In our case the assessor is the Dickinson County Assessor located at the Spirit Lake courthouse.

The assessor determines the assessed value of each piece of property in the County. Market value of a property is an estimate of the price that it would sell for on the open market on January First of the year of assessment. This is sometimes referred to as the “arms-length transaction” or “willing buyer/willing seller” concept.

The guidelines and rules for determining assessed value is provided in the 463 page 2020 Iowa Real Property Appraisal Manual issued by the Iowa Department of Revenue. The manual introduction provides a description of appraisal techniques. The manual can be found on the Internet  The technique for assessing dwellings is well documented. There is a section on land values, but no information about valuating lakeshore land. 


The difference between the Assessed Value and Taxable Value is the “State Rollback” factor. This Rollback Factor was implemented by the State of Iowa years ago to reduce the amount of property tax. This roll back factor changes over time and is determined by the Iowa Department of Revenue. For the last five years the rollback factor has been 0.55621. This means your taxable value is about half of your assessed value.

State law limits residential property value increases to 3% using a statewide average. If assessments grow by more than 3% in Iowa, the rollback is adjusted to reduce how much of a home's value is taxed. However, homeowners in areas where assessment increases outpace the statewide average could still exceed 3% and face higher tax bills. 

Major sections of Iowa laws that determine how property tax is determined include: 257, 384, 425, 427, and 441.

The Iowa legislative Services Guide to Property Tax has helpful information – website

More information about Dickinson County property tax procedures can be found on the County Assessor’s  Specific property information can be found on this website by using the Real Estate Search function. Searches can be made by owners name, property address, or parcel number. Included on each property page is a method to calculate the current year property tax.