65 ILCS 5/11-130-11
Any municipality issuing revenue bonds under this Division 130 shall install and maintain a proper system of accounts, showing the amount of revenue received and its application. At least once a year the municipality shall have the accounts properly audited by a competent auditor. The report of that audit shall be open for inspection at all proper times to any taxpayer, water-user, or any holder of bonds issued under this Division 130, or to anyone acting for and on behalf of the taxpayer, water-user, or bondholder.
The treasurer of the municipality shall be custodian of the funds derived from income received from waterworks purchased or constructed either in whole or in part under the provisions of this Division 130. He shall give proper bond for the faithful discharge of his duties as such custodian, and this bond shall be fixed and approved by the corporate authorities of the municipality.
All of the funds received as income from waterworks purchased or constructed in whole or in part under the provisions of this Division 130, and all of the funds received from the sale of revenue bonds issued to construct such a waterworks system, shall be kept separate and apart from the other funds of the municipality. The treasurer shall maintain separate accounts in which shall be placed (1) the interest and sinking fund, (2) the depreciation fund and (3) the operating and maintenance fund. He shall also provide for refunding outstanding certificates payable out of water revenue.
65 ILCS 5/11-130-11