65 ILCS 5/11-134-4

At all times during the term of such a contract the city shall establish, maintain, and collect rates for water supplied or delivered to its water consumers sufficient to enable the city to pay for all water filtered and treated under the terms of the contract at the rates therein provided for. But this provision does not relieve the city from any obligation to maintain such other rates as may be imposed upon it under the terms of any other statutory provision or contract.