A. The board may also levy an additional annual assessment sufficient to care for the cost of operation of the district and the maintenance of its roads, equipment and for payment of the salaries of employees of the district, provided that no such annual assessment for operations, maintenance and salaries shall exceed three (3) mills on the dollar of the assessed valuation of the property in the district.

B. The board may call an election of the registered voters of the district, or if there are no registered voters of the district, the owners of real property in the district who are registered voters, in the manner provided for in Section 902.12 of this title, to determine whether or not the board shall levy an annual assessment not to exceed three (3) mills on the dollar of the assessed valuation of the property in the district for the purpose of providing additional funds for the operation of the district, the maintenance of its roads, equipment and salaries of the employees of the district. Such annual assessment shall be in addition to the annual assessment provided for in subsection A of this section. The number of mills shall be set forth in the resolution calling the election and, if approved, shall remain in effect until increased or decreased in a later election called in the manner provided for in Section 902.12 of this title, but the total additional annual levy shall not exceed three (3) mills.