29 CFR §1450.26
- (a)Refunds shall promptly be made when—
- (1)A debt is waived or otherwise found not owing to the United States (unless expressly prohibited by statute or regulation); or
- (2)The employee's paying agency is directed by an administrative or judicial order to refund amounts deducted from his or her current pay.
- (b)Refunds do not bear interest unless required or permitted by law or contract.