Indiana Code Title 13. Environment § 13-18-11-11

Sec. 11. (a) All water or wastewater treatment plants and water distribution systems, whether publicly or privately owned, must be under the supervision of an operator whose competency is certified to by the commissioner in a classification corresponding to the classification of the plant or distribution system to be supervised.  However, this section does not prohibit a governmental agency, a corporation, or an individual from continuing to employ in that capacity a person in responsible charge of the operations of the works if the person is certified under section 10 of this chapter.

(b) A certified operator may supervise more than one (1) plant or system if it can be shown that adequate supervision to ensure safe and effective operation is provided for all plants and systems supervised.