Iowa Code § 447.4: Redemption from sale for part of tax.

In case a redemption is made of a parcel compromised and assigned for a sum less than the total amount due, the purchaser is entitled to receive only the amount paid and a ratable part of the interest and costs. In determining the interest to be paid upon redemption from sale, the sum due on a parcel sold shall be taken to be the total amount due on the parcel at the time of sale, and the amount paid for a parcel at sale shall be apportioned ratably in accordance with section 447.1. Parcels so sold are redeemable in the same manner and with the same interest as those sold for the taxes of the preceding year.