(a) The district's annual budget must contain a complete financial statement, including a statement of:
(1) the outstanding district obligations;
(2) the amount of cash on hand to the credit of each district fund;
(3) the amount of money received by the district from all sources during the previous year;
(4) the amount of money available to the district from all sources during the ensuing year;
(5) the amount of the balances expected at the end of the year in which the budget is being prepared;
(6) the estimated amount of revenue and balances available to cover the proposed budget; and
(7) the estimated tax rate that will be required.
(b) The board may amend the budget after adoption.
(c) The district may not spend money for an expense not included in the annual budget or an amendment to it unless the board by order declares the expense to be necessary.