N.D. Cent. Code § 61-35-84
At any time after entering into a contract for a project to be financed in whole or in part by special assessments, a district may issue temporary and definitive bonds on the project fund, created for that purpose, in the manner and subject to the limitations prescribed in section 40-24-19. If the bonds are issued to finance a sewer or water project, the net revenues derived from the imposition of service charges to be imposed and collected with respect to the project as provided in section 61-35-68 may be pledged to payment of those bonds, except that the first maturity date of any such bond may not be less than two years from the date of issuance. Bonds issued under this section must be in amounts as in the judgment of the board will be necessary for the project. The bonds must bear interest at a rate or rates and be sold at a price resulting in an average net interest cost not exceeding twelve percent per annum if sold at private sale. There is no interest rate ceiling on bond issues sold at public sale or to the state or any of its agencies or instrumentalities. The bonds must state upon their face the purpose for which they are issued and the project fund from which they are payable and must be signed by the chairman of the board and countersigned by the secretary of the district. The bonds must be payable serially in such amounts as the board determines, extending over a period of not more than thirty years.
N.D.C.C. § 61-35-84