110 ILCS 805/7-8

Before or within the first quarter of each fiscal year, the board shall adopt a budget and pass a resolution to be termed the "annual budget", hereinafter called the "budget", in and by which the board, subject to the limitations in Sections 7-9 through 7-13, shall appropriate such sums of money as may be required to defray all of its estimated expenses and liabilities to be paid or incurred during that fiscal year.