65 ILCS 5/9-2-86
The report of the municipal collector, when so made, shall be prima facie evidence that all the forms and requirements of the law, in relation to the making of the return have been complied with, and that the special assessments, or special taxes, or the matured installments thereof, and the interest thereon, and the interest accrued on installments not yet matured, mentioned in the report, are due and unpaid.
Upon the application for judgment of sale upon such an assessment or matured installments thereof, or the interest thereon, or the interest accrued on installments not yet matured, no defense or objection shall be made or heard which might have been interposed in the proceeding for the making of that assessment, or the application for the confirmation thereof. No errors in the proceeding to confirm not affecting the power of the court to entertain and consider the petition therefor, shall be deemed a defense to the application provided for in this Division 2.
When such an application is made for judgment of sale on an installment only of an assessment payable by installments, all questions affecting the jurisdiction of the court to enter the judgment of confirmation and the validity of the proceedings shall be raised and determined on the first of such applications. On application for judgment of sale on any subsequent installment, no defense, except as to the legality of the pending proceeding, the amount to be paid, or actual payment, shall be made or heard. And it shall be no defense to the application for judgment on any assessment or any installment thereof that the work done under any ordinance for an improvement does not conform to the requirements of that ordinance, if it appears that the work has been accepted by or under the direction of the board of local improvements. And the voluntary payment by the owner or his agent, of any installment, or of any assessment, levied on any lot, block, tract, or parcel of land, shall be held in law to be an assent to the confirmation of the assessment roll, and shall be held to release and waive the right of the owner to enter objections to the application for judgment of sale and order for sale.
The judgment of sale on any installment shall include all interest accrued on the installment up to the date of that judgment of sale, and also the annual interest due as returned delinquent by the municipal collector on any installment or installments not matured. All judgments of sale for a matured installment shall bear interest on the amount of the principal of that matured installment to the date of payment or sale.
65 ILCS 5/9-2-86