65 ILCS 5/9-2-133
When any municipality provides by ordinance for the construction of a waterworks system, any portion of the cost of which is to be paid by special assessment and a direct annual tax is authorized by a vote as provided in Section 9-2-38, in order to secure the payment of the cost of that construction, the contractor and holders of the bonds that may be issued in payment of that cost, in the manner provided in this Division 2, shall have a lien upon the waterworks system, and upon the income to be derived from its operation, to secure the payment of the amounts due them respectively. This lien shall be to the fullest extent that the municipality may be authorized by law to create. Upon a request in writing of the contractor for the construction of such a waterworks system, or of the holders of a majority in amount of the specified bonds, the municipality shall convey by a deed of trust in the nature of a mortgage the waterworks system so to be constructed, and all the property, both real and personal, pertaining thereto. Such a deed of trust shall secure the payment of the assessment for public benefit or of the bonds as the contractor or holders of the bonds may elect. The trustees in such a deed of trust shall be selected by the contractor or the holders of a majority in amount of such bonds. The provisions of this section shall not apply to any city having a population of 500,000 or more.
65 ILCS 5/9-2-133