(1) The proceedings to foreclose the liens against all properties on a general certificate of delinquency or on more than one individual certificate may be brought in one action.

(2) No assessment, costs, or interest may be considered illegal because of any irregularity in the assessment roll or because the assessment roll has not been made, completed, or returned within the time required by law, or because the property has been charged or listed in the assessment roll without name, or in any other name than that of the owner, and no error or informality in the proceedings of any of the officers connected with the assessment may invalidate or in any other manner affect the assessment thereof. Any irregularities or informality in the assessment roll or in any of the proceedings connected with the assessment or any omission or defective act of any officer or officers connected with the assessment may be, at the discretion of the court corrected, supplied, and made to conform to the law by the court. This subsection does not apply if the court finds that the failure to conform to the law unfairly prejudices a party with an interest in the property.

(3) A party with an interest in real property subject to foreclosure within the district may file a written answer within the time permitted by RCW 87.06.040(1)(d) asserting an objection or defense to the entry of a foreclosure judgment against the property. However, defenses or objections shall be limited to: (a) The form of pleading; (b) manner of service; (c) invalidity of the assessments claimed delinquent; (d) payment of the assessments claimed delinquent; or (e) that the real property against which foreclosure is sought is not subject to district assessment. No counterclaim shall be permitted. The court shall liberally permit amendment or supplementation of the district's challenged pleading or procedure to cure the claimed defect.

(4) The court shall determine timely objections or defenses to the district's foreclosure in a summary proceeding based only on the district's pleading and the interested party's answer and shall promptly pronounce judgment granting or denying the foreclosure; or the court may, in its discretion, to provide substantial justice to the parties, continue the case to a later time to hear evidence on the issues raised by the answer. Hearings under this section shall be limited to affidavits or declarations, and shall be expedited.