SDCL § 3-8-4: Dual salaries prohibited.

Except as provided in §§ 3-8-4.1 to 3-8-4.3, inclusive, no person receiving a salary payable out of the state treasury or from the funds of any state institution or department, may, during the period for which such salary has been or is to be paid, receive any other salary from the state or any institution or department thereof.