1. The treasurer of the county in which a drainage district is located shall act as treasurer of the district and shall be the custodian of the funds of the district, except as otherwise provided in this chapter.

2. He shall receive and receipt for all such funds and shall enter into a separate bond for each district in the county in a sum to be fixed by the county commission, not less than the probable amount of funds of said district to be in his possession at any one time. Such bond shall be payable to the district, shall be approved by the county commission, shall be signed by two or more residents of the county or by a surety company authorized to transact business in the state and shall be conditioned for the faithful and prompt disbursement according to law of all such funds as shall from time to time be in his possession. The premium on such bond may be paid by the district.

3. Except as otherwise provided in this chapter, the treasurer shall keep all district funds received by him deposited in a bank or banks selected in the same manner and at the same time that the depositary for county funds is selected. All interest accruing on district funds shall be credited to the district and any premium on a surety bond may be paid by the district.