The legal basis of RadNet originated in Executive Order 10831, which was issued by President Dwight D. Eisenhower in 1959 and was reiterated as part of the legislative history of the 1959 amendments to the Atomic Energy Act (Public Law 86-373)(PDF)Exit.

Radioactive fallout and environmental radiation monitoring became the responsibility of the Department of Health, Education and Welfare (HEW) under these legal mandates. In 1970, HEW transferred these responsibilities to EPA based on Reorganization Plan No. 3. EPA describes these responsibilities in EPA Order 1110.2. In 1973, through its Office of Radiation Programs (ORP), EPA established RadNet by consolidating various components of the various radiation monitoring networks that had been developed to that point, including the Radiation Alert Network, the Tritium Surveillance System, the Interstate Carrier Drinking Water Network, and the Pasteurized Milk Network. The responsibility for operating RadNet currently is assigned to the Director of the National Air and Radiation Environmental Laboratory (NAREL), Montgomery, Alabama.