Ind. Code § 8-1-6-3
The term "public utility", as used in this chapter, shall mean and embrace every corporation, company, cooperative organization of any kind, individual, association of individuals, their lessees, trustees, or receivers appointed by any court whatsoever that on or after March 15, 1969, may own, operate, manage, or control any plant or equipment within the state for the conveyance of telegraph or telephone messages, or for the production, transmission, delivery, or furnishing of heat, light, water, or power, or for the collection, treatment, purification, and disposal in a sanitary manner of liquid and solid waste, sewage, night soil, and industrial waste, for service directly or indirectly to the public, but said term shall not include a municipality that may after March 14, 1969, acquire, own, or operate any of the foregoing facilities.
The term "gross revenue", as used in this chapter, shall include all intrastate operating revenue received by a public utility for the conveyance of telegraph or telephone messages or for the production, transmission, delivery, or furnishing of heat, light, water, or power, or for the collection, treatment, purification, or disposal in any sanitary manner of liquid or solid waste, sewage, night soil, and industrial waste for service directly or indirectly to the public. Provided, however, that such term shall not include revenue derived by a public utility in the sale of public utility services, products, or commodities to another public or municipal utility for resale by the latter.
IC 8-1-6-3