N.D. Cent. Code § 40-29-11: Payment of assessments - Interest

All assessments for sidewalks must be payable in equal annual amounts extending over a period not exceeding twenty years and must bear interest at an annual rate of not more than two percentage points above the average net annual interest rate on warrants for the total amount of the assessments remaining unpaid. Anyone may pay the sidewalk assessment in one single payment, and anyone who has paid one or more installments may pay the balance in one payment.