Iowa Code § 359A.12: Division by agreement — record.

The several owners may, in writing, agree upon the portion of partition fences between their lands which shall be erected and maintained by each, which writing shall describe the lands and the parts of the fences so assigned, be signed and acknowledged by them, and filed and recorded in the office of the recorder of deeds of the county or counties in which they are situated. The county recorder shall collect fees specified in section 331.604.