BLADENSBURG, IOWA -- Every fall, the State of Iowa tells county auditors to equalize or adjust property tax assessment values.

Van Buren, Wapello, Monroe, and Jefferson counties did not have to make any adjustments this fall, but it has happened in the past.

KTVO checked in with the Wapello County Assessor to see how values are adjusted.

"The state uses our 2010 sales values against our 2000 assessed values and if there's a big difference, they want it evened out," said Gary Smith. "Different counties have different levels that they have to hit and if we don't do it, the state will do it."

Last April, Wapello County did see a 30% increase in agricultural property tax assessment values because of the higher crop prices. Unlike residential and commercial property, agricultural properties are assessed based on their productivity.

In a press release, the Iowa Department of Revenue says equalizing the assessment levels among counties is necessary to ensure the fair distribution of school aid and other state services.

For more information, see the Iowa Department of Revenue's press release.