(2) The board of the district in which indebtedness was incurred under this section shall levy an annual tax on all taxable property in the district sufficient to meet the interest payments and retire the indebtedness, but no tax shall be necessary where other provisions are made for payment of the indebtedness. [1971 c.513 §53; 1983 c.124 §10; 1985 c.356 §5; 1993 c.97 §26; 2007 c.783 §139]