Town Hall #38

The Property Tax Cycle

Property Assessments

The “Rollback”


Iowa’s property tax cycle is an 18-month process. It begins with an assessment of the market value of properties as of January 1, and is completed with property tax bills being sent in August of the following year.

Chapter 428.4 of the Iowa Code requires that a reassessment of all property be conduced as of January 1 of each odd-numbered year (eg. 2021). Adjustments to specific properties may be done in even-numbered years (2022) should circumstances warrant.

Once the market value of a property is determined, a “rollback” percentage is applied to determine the taxable value of the property. It is this value to which a tax levy is applied to determine the property tax bill.

Guest Presenter:

Randy Ripperger, Polk County Assessor

Randy Ripperger received a Bachelor of Arts degree in Economics from Central College in Pella, Iowa and has been with the Polk County Assessor’s Office since 1980, serving as Chief Deputy Assessor from 2007 to 2014 and as Assessor since 2014. In 2017 assumed the office of President of the International Association of Assessing Officers (IAAO).


  • The property tax cycle
  • How and when assessed values are determined
  • The basics of the “rollback.”
  • Current trends


  • Property Tax Cycle Graphic
  • Slide Deck
  • Video of session
    • 06:42 Biennial Assessments
    • 09:40 Mass vs Single Property Assessments
    • 13:00 Valuation Methods
      • Cost, sales, income, & market trend
    • 23:00 The “Rollback”
      • Assessed value x rollback = taxable value
    • 27:00 Determining tax taxes & bills
    • 32:41 Measuring Appraisal Performance
    • 36:44 A look at preliminary 2023 trends
    • 38:04 A review of 2022 Assessments
    • 39:30 “Horseshoes & Hand Grenades”
    • 40:01 Polk County vs state average