Amends the Property Tax Code. Provides for a non-binding, advisory referendum on the question of whether a taxing district should reduce its aggregate extension by up to 10% from its aggregate extension for the previous taxable year. Provides that the referendum shall be initiated by a petition signed by a number of registered voters of the taxing district that is equal to or greater than 1% but less than 5% of the total number of votes cast in the taxing district in the preceding general election. Provides for a binding referendum on the question of whether a taxing district shall reduce its aggregate extension by up to 10% from its aggregate extension for the previous taxable year. Provides that the referendum shall be initiated by a petition signed by a number of registered voters of a taxing district that is equal to or greater than 5% of the total number of votes cast in the taxing district in the preceding general election. Preempts the power of home rule units to tax. Effective immediately.