Iowa Code § 904.405
The director shall cause the testimony taken at the investigation to be recorded. The recording of the testimony shall not be transcribed unless the testimony is part of a case that is appealed or an interested party requests a transcript and pays the cost of preparing the transcript. The recording of the testimony, or the transcription thereof, shall be filed and maintained in the director's office at the seat of government for at least five years from the date the testimony is taken or the date of a final decision in a case involving the testimony, whichever is later. However, a recording of testimony involving any employee of the department shall continue to be filed and maintained until the employee no longer is employed by the department.
Iowa Code § 904.405