35 ILCS 200/20-115
The county collector shall, on the first of every month, report to the county clerk, in writing, which may be transmitted electronically, the amount of county tax received during the preceding month. The county collector shall keep the account as collector of taxes separate from the account as county treasurer. He or she shall credit the account as collector with the amount of his or her monthly reports to the county clerk, and with the amount of bankruptcies, removals, errors, forfeitures, and other credits allowed him or her on settlement with the county board. As county treasurer, he or she shall charge himself or herself with the amount shown in his or her monthly report to the county clerk and such other amounts as may be received as county treasurer. The county board may examine the account and vouchers at any time, by committee or otherwise.
35 ILCS 200/20-115