70 ILCS 3705/13
The board of trustees shall establish the beginning and ending of the fiscal year for the district, which shall constitute its budget year, and at least thirty days prior to the beginning of the first full fiscal year after the creation of the district, and annually thereafter, the general manager shall prepare and submit to the board a tentative budget which shall include all operation and maintenance expenses for the ensuing fiscal year. Such tentative budget shall be considered by the board and be subject to any revisions or amendments as may be determined by such Board, shall be adopted as the budget for the ensuing fiscal year, and no expenditures for operation and maintenance expenses in excess of the budget shall be made during such fiscal year, unless unanimously authorized and directed by the board. It shall not be necessary to include in such budget any statement of necessary expenditures for interest or principal payments on bonds or for capital outlays, but it shall be the duty of the Board to make provision for their payment as they become due.
70 ILCS 3705/13