Iowa Code § 297.6: Condemnation.

If the owner of real estate desired for any purpose for which any school may be authorized to take and hold real estate refuses to convey the same, or is dead or unknown or cannot be found, or if in the judgment of the board of directors of the corporation they cannot agree with such owner as to the price to be paid therefor, such real estate may be taken under condemnation proceedings in accordance with the provisions of chapter 6B.