70 ILCS 605/4-10
If, for any reason, a vacancy occurs in the office of commissioner in a district in which the commissioners are appointed the appointing authority may appoint a successor, either without notice or upon such notice as the appointing authority may direct, to fill the vacancy until the first Tuesday of September next, on which date, or as soon thereafter as may be feasible, the appropriate appointing authority shall appoint a successor for the remainder of the term, in accordance with Sections 3-9, 4-1 and 4-2. For good cause shown any commissioner, whether elected or appointed, may be removed from office by the appointing authority upon its own motion or upon the motion of any interested landowner. Notice to such commissioner of the hearing on such motion shall be given as the appointing authority shall direct.
70 ILCS 605/4-10