70 ILCS 3405/10
A majority of the board of trustees shall constitute a quorum, but a smaller number may adjourn from day to day. No trustee or employee of the district shall be directly or indirectly interested financially in any contract, work or business or the sale of any article, the expense, price, or consideration for which is paid by said district; nor in the purchase of any real estate or other property, belonging to the district, or which shall be sold for taxes or assessments or by virtue of legal process at the suit of the district. However nothing herein shall be construed as prohibiting the appointment or selection of any person as a trustee or employee whose only interest in the district is as an owner of real estate in the district or of contributing to the payment of taxes levied by said district. The trustees shall provide and adopt a corporate seal for the district.
70 ILCS 3405/10