N.D. Cent. Code § 21-03-38
All borrowed money must be paid into the treasury of the municipality borrowing it, must be kept there until used, in a fund separate and distinct from all other funds, to be used for the purpose for which it was borrowed and for no other purpose except that such funds may be temporarily invested in securities as are approved by the governing board in accordance with the provisions of section 21-03-43 and as otherwise provided by section 21-03-42, and may be withdrawn only upon order or warrants made payable out of said fund and expressing the purpose for which they were drawn. The purchaser of any bonds issued pursuant to this chapter is not obliged to see to the application of the purchase price thereof, but is protected fully in paying for such bonds by the receipt of the county treasurer or of the officer delivering such bonds. Income from the temporary investing of receipts from bond issues must be available for use for such purpose as such bond issue was approved or, upon resolution of the governing body of the municipality, must be paid into the sinking fund for use in payment of bonds issued.
N.D.C.C. § 21-03-38