75 ILCS 5/3-1
In any city of 500,000 or fewer inhabitants, the corporate authorities shall levy a tax for library purposes of not to exceed .15% of the value of all the taxable property in the city, as equalized or assessed by the Department of Revenue. If the annual public library tax rate of an established library was increased above .12% up to .20% prior to 1972 as provided in this Act, the corporate authorities shall then levy up to an additional .03% above the increased rate approved at the election. If, however, the corporate authorities desire to increase the tax rate but not in excess of .60% of value for such purposes, the corporate authorities may, by ordinance, stating the tax rate desired, direct that a proposition be submitted to the voters of the city at any regular election. The proposition shall be in substantially the form prescribed in Section 3-3. If a majority of the votes cast upon the proposition are in favor thereof, the corporate authorities may thereafter levy annually a tax for library purposes at the authorized increased rate. Any tax levied pursuant to Section 3-9 shall be disregarded in applying the provisions of this Section.
The corporate authorities may also levy an additional tax of .02% of the value of all the taxable property in the city, as equalized or assessed by the Department of Revenue, for the purchase of sites and buildings, for the construction and equipment of buildings, for the rental of buildings required for library purposes, and for maintenance, repairs and alterations of library buildings and equipment. In any year in which the corporate authorities propose to levy such additional .02% tax, the corporate authorities shall adopt a resolution determining to levy such tax. Within 15 days after the adoption of the resolution, it shall be published at least once in one or more newspapers published in the city, or if no newspaper is published therein, then in one or more newspapers with a general circulation within the city. In a city in which no newspaper is published, publication may instead be made by posting a notice in three prominent places within the city. The publication or posting of the resolution shall include a notice of (1) the specific number of voters required to sign a petition requesting that the question of the adoption of the resolution be submitted to the electors of the city; (2) the time in which the petition must be filed; and (3) the date of the prospective referendum. The city clerk shall provide a petition form to any individual requesting one. If no petition is filed with the corporate authorities within 30 days after publication or posting of the resolution, or if all petitions so filed are determined to be invalid or insufficient the city shall then be authorized to levy the tax. However, if within the 30 day period, a petition is filed with the corporate authorities, signed by electors of the city equal in number to 10% or more of the total number of registered voters in the city, asking that the question of levying such a .02% tax be submitted to the electors of the city, the question shall be submitted at an election. Notice of this referendum shall be given as provided by the general election laws of the state, and the referendum shall be held in all respects in accordance with those laws. The proposition shall be in substantially the following form: "Shall the corporate authorities of (name of city) be authorized to levy an additional tax of ....% for the construction of buildings, provision of sites, etc., as determined by resolution dated (insert date)?". If a majority of votes cast upon the proposition are in favor thereof, the corporate authorities may levy the additional tax.
75 ILCS 5/3-1