Ill. Admin. Code tit. 86 § 515.100
For the purposes of this Part:
"non-residential sewer service" means sewer utility service that is not residential sewer service. [305 ILCS 21/25 ]
"non-residential water service" means water utility service which is not residential water service. [305 ILCS 21/25 ]
"residential sewer service" means sewer utility service for household purposes delivered to a dwelling of 2 or fewer units that is billed under a residential rate, or sewer service for household purposes delivered to a dwelling unit or units that is billed under a residential rate and is registered by a separate meter for each dwelling unit. [305 ILCS 21/25 ]
"residential water service" means water utility service for household purposes distributed to a dwelling of 2 or fewer units that is billed under a residential rate, or water service for household purposes distributed to a dwelling unit or units that is billed under a residential rate and is registered by a separate meter for each dwelling unit. [305 ILCS 21/25 ]
"water or sewer provider" means:
any public utility providing water or sewer services under the jurisdiction of the Illinois Commerce Commission;
any other utility providing water or sewer service owned by a municipality, township, county, or other political subdivision of this State; or
any other entity that is not a public utility under the jurisdiction of the Illinois Commerce Commission that regularly provides water or sewer service. [305 ILCS 21/10 ]
Ill. Admin. Code tit. 86, § 515.100