Idaho Code § 39-175B
The legislature cannot conveniently or advantageously set forth in this chapter all the requirements of all of the regulations which have been or will be established under the clean water act. However, any state permitting program must avoid the existence of duplicative, overlapping or conflicting state and federal regulatory systems. Further, the board may promulgate rules to implement a state permitting program but such rules shall not impose conditions or requirements more stringent or broader in scope than the clean water act and regulations adopted pursuant thereto. Further, the department will not require Idaho pollutant discharge elimination system (IPDES) permits for activities and sources not required to have permits by the United States environmental protection agency.
Idaho Code § 39-175B