70 ILCS 405/18

Certificate evidence of organization. In any suit, action, or proceeding involving the validity or enforcement of, or relating to, any contract, proceeding, or action of the district, the district shall be deemed prima facie to have been established in accordance with the provisions of this Act upon proof of the issuance of the aforesaid certificate by the Secretary of State. A copy of such certificate duly certified by the Secretary of State shall be admissible in evidence in any such suit, action, or proceeding and shall be proof of the filing and contents thereof.