Iowa county assessors are currently in the process of mailing new assessment notices for all classes of property. The new valuations will not be used for taxation until the spring of 2018, when the fiscal 2019 budgets are finalized.

Taxes on the new assessments will be paid beginning in September 2018.

The new notices will just show the assessed value and not the taxable value. That’s because the final percentage of the rollback will not be determined until October.

The preliminary productivity values for agricultural land for the 2017 assessment year decreased for the first time since 2003, according to the Iowa Department of Revenue. The statewide average assessment for an acre of land based on productivity dropped 10.6 percent to $1,926 an acre.

New data from 2014 and 2015 were incorporated into the five-year moving...