At the same time a petition for a declaratory order is filed, the petitioner shall serve the petition, in accordance with the "Service of documents" subrule in 199-Chapter 7 and the "Electronic service" rule in 199-Chapter 14, upon any person who, based upon a reasonable investigation, would be a necessary party to the proceeding under applicable substantive law. The petitioner is to file with the commission a list of all persons served.
Iowa Admin. Code r. 199-4.4