Ill. Admin. Code tit. 44, § 8.2025
b) Conditions for Use of Sole Source Procurement. Sole source procurement is permissible when a requirement is available from only a single supplier or when only one supplier or service provider is deemed economically feasible. A requirement for a particular proprietary item does not justify a sole source procurement if there is more than one vendor authorized to provide that item. The following are examples of circumstances that could necessitate sole source procurement (but are not exhaustive):
3) non-competitive public utility services;
c) Changes
A change that is germane and reasonable in scope and cost in relation to the original contract that is necessary or desirable to the success of the project need not comply with these sole source procedures.
d) Sole Source Determination and Hearing