30 ILCS 20/4
No funds, monies, or other things of value, in the hands of the treasurer of any public or municipal corporation, shall be paid out, disbursed or delivered, except upon warrant, draft, electronic funds transfer, or order signed and countersigned by the officers of the public or municipal corporation authorized to sign and countersign the same. Such funds may be disbursed by the treasurer, by check issued or signed by him or his authorized deputy. If required by statute, ordinance or resolution such check shall be countersigned by an officer or agent of the public or municipal corporation on whose behalf such disbursement is made. This provision shall apply to all treasurers, including county treasurers and ex-officio county collectors of taxes and special assessments, and to all payments, disbursements or deliveries, whether under the order of a court or otherwise.
30 ILCS 20/4