N.D. Cent. Code § 57-15-20
The general fund levy in a civil township, exclusive of levies to pay interest on any bonded debt and to provide a sinking fund to pay and discharge the principal of bonded debt at maturity, may not exceed the amount produced by a levy of eighteen mills on the dollar of the taxable valuation of property in the township.
Upon approval of a majority of electors of the township voting on the question, a civil township general fund levy may be increased by an additional amount not to exceed the amount produced by a levy of eighteen mills on the dollar of the taxable valuation of property in the township. The increased levy under this section may be made only if notice of the question of the approval of such levy has been included with or upon the notice of the annual meeting provided for in section 58-04-01. An excess levy approved by electors of a township under chapter 57-17 before January 1, 2015, may continue to be imposed for five taxable years or the period of time for which it was approved by the electors, whichever is less, under the provisions of law in effect at the time it was approved. After January 1, 2015, approval by electors of increased levy authority under this section may not be effective for more than five taxable years.
N.D.C.C. § 57-15-20