(1) The governing body of a county in which a special improvement district or maintenance district is located may invest maintenance, interest, and sinking fund money of the district in time deposits of a bank, savings and loan association, or credit union insured by the federal deposit insurance corporation or by the national credit union administration or invested in direct obligations of the United States government.
(2) Interest collected on the deposits or investments must be credited to the fund from which the money was withdrawn.