620 ILCS 45/16
Before issuing any bonds as provided in this Act, the county board or governing body of the respective governmental unit shall adopt a resolution specifying the amount of bonds to be issued, the date, denominations, rate of interest and maturities, and fix all the details with respect to the issue and execution thereof, and shall levy a tax sufficient to pay both the principal of and interest upon such bonds as they mature. Such bonds issued in compliance with Section 13 hereof, shall mature at such time or times as the county board or other governing body shall fix, but not in excess of twenty (20) years from date thereof. Any such bonds, the final maturity of which is within such maturity limitation heretofore mentioned in Section 13, shall mature at such times as the county board or the governing body of the other respective taxing districts shall fix within such said maturity limitation heretofore mentioned. All of such bonds shall bear interest at a rate not to exceed the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract, payable semi-annually, and shall be payable at such place as the county board or the governing body of the respective taxing districts shall fix.
With respect to instruments for the payment of money issued under this Section either before, on, or after the effective date of this amendatory Act of 1989, it is and always has been the intention of the General Assembly (i) that the Omnibus Bond Acts are and always have been supplementary grants of power to issue instruments in accordance with the Omnibus Bond Acts, regardless of any provision of this Act that may appear to be or to have been more restrictive than those Acts, (ii) that the provisions of this Section are not a limitation on the supplementary authority granted by the Omnibus Bond Acts, and (iii) that instruments issued under this Section within the supplementary authority granted by the Omnibus Bond Acts are not invalid because of any provision of this Act that may appear to be or to have been more restrictive than those Acts.
620 ILCS 45/16