The treasurer of each county in which a district, or a part of a district, is situated shall collect all district taxes and special assessments together with any penalty and interest thereon in the same manner as county taxes are collected, and shall, within twenty days after the close of each month, pay to the treasurer of the district those taxes and assessments collected during the preceding month, and shall notify the secretary of the district of the payment. In June and December of each year, and as the county commission may otherwise require, the district treasurer shall report to each member of the water resource board the amount of money in the district treasury, the amount of receipts in the preceding month, and items and amounts of expenditures. At each regular meeting of the board the treasurer shall submit to the board a statement of the district’s finances.

Each district may invest any money in the district treasury, including money in any sinking fund established for the purpose of providing for the payment of the principal or interest of any contract, bond, or other indebtedness or for any other purpose, not required for the immediate needs of the district, in accordance with chapter 21-04.

Funds of the district shall be paid out or expended only upon the authorization or approval of the water resource board and by check, draft, warrant, or other instrument in writing, signed by the treasurer, assistant treasurer, or any other officer, employee, or agent of the district authorized by the treasurer to sign on behalf of the treasurer. The authorization shall be in writing and filed with the secretary of the district.