65 ILCS 125/75

Any petition required by this Act must be signed by property owners in the proposed business improvement district or proposed expanded area of a business improvement district, as the case may be, who cumulatively are expected to pay more than 50% of the total amount of the district charges proposed to be levied. All signatures for a petition to establish or expand a business improvement district must be collected within a period ending no more than 120 days from the initiation of the petition, which date shall be specified on the petition.