If Iowa Administrative Code, then scroll to find the agency that governs the chapter (e.g. Inspections and Appeals - 481; Public Safety - 661; Elder Affairs - 321; Professional Licensure - 645).
Then, scroll to find the chapter you are looking for (e.g. Ch. 58, Ch. 61, or Ch. 56 under Inspections and Appeals; Ch. 5 under Public Safety; Ch. 27 under Elder Affairs; Ch. 140, 141, 142, 143, 144 under Professional Licensure).