Ill. Const. art. VII, § 8

DISTRICTS AND UNITS OF LOCAL GOVERNMENT OTHER THAN COUNTIES AND MUNICIPALITIES Townships, school districts, special districts and units, designated by law as units of local government, which exercise limited governmental powers or powers in respect to limited governmental subjects shall have only powers granted by law. No law shall grant the power (1) to any of the foregoing units to incur debt payable from ad valorem property tax receipts maturing more than 40 years from the time it is incurred, or (2) to make improvements by special assessments to any of the foregoing classes of units which do not have that power on the effective date of this Constitution. The General Assembly shall provide by law for the selection of officers of the foregoing units, but the officers shall not be appointed by any person in the Judicial Branch. (Source: Illinois Constitution.)