65 ILCS 5/9-2-7
In cities having a population of 500,000 or more, there is created a board of local improvements consisting of the superintendent of special assessments and 5 other members. These 5 other members shall be nominated by the mayor and shall be confirmed by the city council. None of the members of the board, except the superintendent of special assessments, shall hold any other office or position in any government department of the city. The Board shall elect from its members a president, a vice president, and an assistant secretary. The superintendent of special assessments shall be ex-officio secretary of the board. In the absence or the inability of the president or secretary to act, the vice president for the president and the assistant secretary for the secretary have full power to sign and execute contracts, vouchers, bonds, payrolls, and all other papers, documents, and instruments necessary. The board shall hold regular and special sessions, as it may determine, for the transaction of all business in rooms accessible to the public, to be provided by the city council. The city council of the city shall provide for salaries for the board of local improvements.
In cities having a population of 50,000 or more and less than 500,000, there is created a board of local improvements consisting of 6 members, of which board the commissioner of public works shall be the president. The other members of this board shall be the superintendent of streets, the superintendent of sewers, the superintendent of special assessments, the city engineer and the city clerk, or if there is no office of City Clerk, the City Comptroller.
In cities having a population of less than 50,000, and in villages and incorporated towns, the board of local improvements shall consist of the mayor of the city, or the president of the village or incorporated town, and the public engineer and the superintendent of streets of the municipality, where such officers are provided for by ordinance. But if at any time such officers are not so provided for, the corporate authorities, by ordinance, shall designate 2 or more members of their body who, with the mayor or president of the village or incorporated town shall constitute the members of the board, until otherwise provided by ordinance. The mayor or president, as the case may be, shall be president of the board.
The corporate authorities of any municipality having a population of more than 18,000 and less than 100,000, may provide by ordinance for the payment of salaries to the members of the board of local improvements, but if any member of such a board holds any other office in the government of that municipality, his salary as member of the board shall not exceed the sum of $100 per month.
However, in cities, having a population of less than 100,000, and in villages, where such cities and villages prior to or after the effective date of this Code adopt the commission form of municipal government, corporate authorities of such cities and villages may provide by ordinance that the board of local improvements shall consist of the mayor and any 2 or more of the commissioners, regardless of whether or not the offices of public engineer and superintendent of streets are provided for by ordinance.
65 ILCS 5/9-2-7