70 ILCS 3105/11
The board of any district, when so requested by the treasurer of the district, shall designate one or more banks or savings and loan associations in which the funds and moneys received by the treasurer, by virtue of his office, may be deposited.
When a bank has been designated as a depository it shall continue as such until 10 days have elapsed after a new depository is designated and is qualified. When a new depository is designated, the district shall notify the sureties of the treasurer of that fact in writing at least 5 days before the transfer of funds.
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 "An Act relating to certain investments of public funds by public agencies", approved July 23, 1943, as now or hereafter amended.
70 ILCS 3105/11