5 U.S.C. § 3375

(a) Appropriations of a Federal agency are available to pay, or reimburse, a Federal or State or local government employee in accordance with— (1) subchapter I of chapter 57 of this title, for the expenses of— (A) travel, including a per diem allowance, to and from the assignment location; (B) a per diem allowance at the assignment location during the period of the assignment; and (C) travel, including a per diem allowance, while traveling on official business away from his designated post of duty during the assignment when the head of the Federal agency considers the travel in the interest of the United States; (2) section 5724 of this title , for the expenses of transportation of his immediate family and of his household goods and personal effects to and from the assignment location; (3) section 5724a(a) of this title , for the expenses of per diem allowances for the immediate family of the employee to and from the assignment location; (4) section 5724a(c) of this title , for subsistence expenses of the employee and his immediate family while occupying temporary quarters at the assignment location and on return to his former post of duty; (5) section 5724a(g) of this title , to be used by the employee for miscellaneous expenses related to change of station where movement or storage of household goods is involved; and (6) section 5726(c) of this title , for the expenses of nontemporary storage of household goods and personal effects in connection with assignment at an isolated location. (b) Expenses specified in subsection (a) of this section, other than those in paragraph (1)(C), may not be allowed in connection with the assignment of a Federal or State or local government employee under this subchapter, unless and until the employee agrees in writing to complete the entire period of his assignment or one year, whichever is shorter, unless separated or reassigned for reasons beyond his control that are acceptable to the Federal agency concerned. If the employee violates the agreement, the money spent by the United States for these expenses is recoverable from the employee as a debt due the United States. The head of the Federal agency concerned may waive in whole or in part a right of recovery under this subsection with respect to a State or local government employee on assignment with the agency. (c) Appropriations of a Federal agency are available to pay expenses under section 5742 of this title with respect to a Federal or State or local government employee assigned under this subchapter.