70 ILCS 2605/9.7

All bonds of the Sanitary District whether heretofore or hereafter issued, not paid at their maturity shall bear interest at the rates specified in the bonds from their due dates until paid and all unpaid coupons evidencing interest upon its bonds shall bear interest at the rate specified in the bonds to which such coupons pertain, from the due dates of such coupons until payment thereof and the corporate authorities of such Sanitary District are authorized to make such payment of interest from any available revenues derived from taxes or otherwise and to levy sufficient taxes upon all taxable property within the territorial limits thereof for the purpose of procuring money to meet such interest payments or to reimburse funds from which such payments have been made.