N.D. Cent. Code § 61-35-68
A district constructing a sewer or water improvement under the special assessment method may resolve in the resolution or ordinance required by section 61-35-52, that a portion of the cost of the improvement must be raised by service charges for the use of the improvement and of the utility of which it forms a part. If the district so resolves, it may determine in its resolutions, ordinances, and other proceedings relating to the levying of special assessments and the issuing of bonds to pay the cost of such improvement, that a specified portion or all of such cost must be assessed specially against any property specially benefited and may cause to be assessed only the portion so determined. In that event the entire remainder of the cost, including interest as well as principal of any bonds issued, over and above the amount of special assessments actually collected and received from time to time in the fund of the improvement district, must be paid from the net revenues derived from the service charges. All of the applicable provisions of this chapter relating to special assessments are applicable to such improvements except as to the portion of the cost of improvements resolved or ordained to be paid by service charges. The board of the district shall provide for the establishment, imposition, and collection of service charges for the services furnished by the improvement and the utility of which it forms a part, and in that connection it has all the rights and powers respecting such service charges as it would have with respect to like matters if the improvement were made in accordance with chapter 40-35. The net revenues derived from the imposition and collection of the service charges or any portion of the service charges as are determined by the board in the resolutions and ordinances must be paid into the appropriate improvement district funds created under section 61-35-83. The revenues when collected must be used and applied in the same manner as moneys paid into such funds from the collection of special assessments. The board of any district issuing bonds to finance any such improvement, in its resolutions and ordinances, may establish an assessment reserve in the fund of the improvement district, to which it may appropriate net revenues of the utility or system from time to time received in excess of amounts required, with special assessments then on hand, to meet the principal and interest next due on the bonds. Before November first of any year the district may by resolution determine the proportion which the amount then on hand in the assessment reserve, and irrevocably appropriated to the payment of the bond, bears to the aggregate amount of the installment of the special assessments levied for the improvement which is payable in the following year, including interest. The district may direct the auditor to reduce, by not more than a proportionate amount, the total of that installment and interest which would otherwise be placed upon the tax list of the district for the current year, against each lot and tract of land assessed or taxed for improvement. If the installment of the special assessment on any property has been prepaid, the board may direct the district to refund, out of the assessment reserve, to the owner of the property at the time of the refund as indicated in the records of the recorder of the county, a sum not exceeding a similar proportion of the principal amount of such installment, excluding interest.
N.D.C.C. § 61-35-68