70 ILCS 1863/25
Regular meetings of the Board shall be held at least once in each calendar month, the time and place of such meetings to be fixed by the Board. Three members of the Board shall constitute a quorum for the transaction of business. All action of the Board shall be by ordinance or resolution and the affirmative vote of at least 3 members shall be necessary for the adoption of any ordinance or resolution. All such ordinances and resolutions before taking effect shall be approved by the chair of the Board, and if the chair approves, the chair shall sign the same, and if the chair does not approve the chair shall return to the Board with his or her objections in writing at the next regular meeting of the Board occurring after passage. But in the case the chair fails to return any ordinance or resolution with the objections within the prescribed time, he or she shall be deemed to have approved the ordinance or resolution and it shall take effect accordingly. Upon the return of any ordinance or resolution by the chair with objections, the vote shall be reconsidered by the Board, and if, upon such reconsideration of the ordinance or resolution, it is passed by the affirmative vote of at least 4 members, it shall go into effect notwithstanding the veto of the chair. All ordinances, resolutions and all proceedings of the District and all documents and records in its possession shall be public records, and open to public inspection, except such documents and records as are kept or prepared by the Board for use in negotiations, legal actions or proceedings to which the District is a party.
70 ILCS 1863/25