Iowa Code § 613.9: Service on state.

Service upon the state shall be made by serving a copy of the original notice with a copy of the petition upon the county attorney for the county, or counties, in which the real estate is located, and by sending a copy of the original notice and petition by certified mail to the attorney general, at Des Moines. The state shall appear within thirty days after the day such notice is served upon the county attorney or within thirty days after such notice is mailed to the attorney general, whichever is later.