Iowa Code § 468.142: District by mutual agreement — presumption.

The owners of lands may provide by mutual agreement in writing duly signed, acknowledged, and filed with the auditor for combined drainage of their lands by the location and establishment of a drainage district for such purposes and the construction of drains, ditches, settling basins, and watercourses upon and through their said lands. Such drainage district shall be presumed to be conducive to the public welfare, health, convenience, or utility.