(50 ILCS 460/25)
    Sec. 25. Interest on assessments. The unpaid portion of any assessment imposed under a special assessment proceeding may bear interest at an interest rate or rates not exceeding the rate or rates on bonds permitted by the Bond Authorization Act; provided, however, that the time of the adoption of the special assessment ordinance shall be the date that the maximum rate or rates shall be calculated rather than at the time the contract is made for the sale of the bonds, as provided in the Bond Authorization Act. Notwithstanding the foregoing provision, from and after the due date of any installment of an assessment, the following additional rates and charges may be imposed with respect to the delinquent amount of such installment:
        (a) an additional rate of interest of 1 1/2% per
    
month; and
        (b) a collection charge of not to exceed 1% of the
    
amount of the delinquent installment.
(Source: P.A. 90-480, eff. 8-17-97.)