83 Ill. Adm. Code 600.50
Definitions
Section 600
Section 600.50 Definitions
The word "Commission," used in this Part, shall be
construed to mean the Illinois Commerce Commission.
The word "customer," used in this Part, shall be
construed to mean any person, firm, or corporation, municipality or other
political subdivision of the state taking water service from any such utility.
The word "utility," used in this Part, shall be construed
to mean public utility.