Mahaska County Courthouse

Assessor: Why Did My Assessed Value Change?

In Iowa, property is reassessed every two years (odd numbered.) The Assessor is continually doing market analysis of sales in their jurisdiction to determine the equitable assessments of property. During reassessment years, if the Assessor needs to make adjustments to certain market areas, or the entire county, they must do so in order to avoid state equalization orders issued by the Iowa Department of Revenue.

The Assessor may also do a reappraisal of the entire county at once. This is a large project and requires several years of planning and budgeting, as well as on-site property inspections. Mahaska County's next reappraisal project will focus on residential and ag dwellings, and will begin in 2029; the newly established values will apply to the 2031 assessment year. More information about the project will be published closer to the date. Reappraisals result in up-to-date and accurate property records in the Assessor's Office, and create a more accurate assessed value for each property.

If a property owner reports changes to a property that result in a valuation change, such as additions to dwellings, demolition of buildings, etc, the Assessor must list those changes and determine the new valuation.  This is done annually. You can report changes through the Beacon website or by contacting our office.

The Assessor will notify property owners of their new assessments with an assessment roll that is postmarked no later than April 1st of the year the assessment is effective for. In Mahaska County, we mail assessment rolls only to property owners whose values have changed. We do not mail assessment rolls to every property owner every year. When property values are equalized by the state, resulting in an increase in valuation, the County Auditor will mail notices to the affected property owners in the fall of the equalization year. No notices are sent when the equalization order results in a downward change in value; however, a general notice will be posted in the local newspaper.


Here are some factors to consider when looking at your assessed value:

  1. What did I pay for the property?
  2. What would I sell the property for?
  3. How much money have I spent improving the property?
  4. Did I do any of the work myself, which results in lower construction costs but would not affect what I would ask for the property on the open market?
  5. Am I questioning the assessed value, or my tax bill?
  6. Am I interested in learning the process by which assessed valuations are determined?
  7. Have I visited the Assessor's Office recently, or used the Sales Reports on the website, to see what properties are currently selling for in Mahaska County?