70 ILCS 1831/125
All funds deposited by the treasurer in any bank or savings and loan association shall be placed in the name of the District and shall be withdrawn or paid out only by check or draft upon the bank or savings and loan association, signed by the treasurer and countersigned by the chairman of the Board. Subject to prior approval of such designations by a majority of the Board, the chairman may designate any other Board member or any officer of the District to affix the signature of the chairman and the treasurer may designate any other officer of the District to affix the signature of the treasurer to any check or draft for payment of salaries or wages and for payment of any other obligation of not more than $2,500.
No bank or savings and loan association shall receive public funds as permitted by this Section, unless it has complied with the requirements established pursuant to Section 6 of the Public Funds Investment Act.
In case any officer whose signature appears upon any check or draft issued pursuant to this Act, ceases to hold his or her office before the delivery thereof to the payee, his or her signature nevertheless shall be valid and sufficient for all purposes with the same effect as if he or she had remained in office until delivery thereof.
70 ILCS 1831/125