(a) Upon its own initiative or upon reasonable complaint made against any public utility including the Virgin Islands Water and Power Authority that any of the rates, tolls, charges, or schedules, or services, or time and conditions of payment, or any joint rate or rates, schedules, or services, are in any respect unreasonable or unjustly discriminatory, or any service in connection therewith, is in any respect unreasonable, insufficient, or unjustly discriminatory, or that any service is inadequate or cannot be obtained, or any billing for service inaccurate or erroneous the Commission may, in its discretion, proceed, with or without notice, to make such investigation as it may deem necessary or convenient. But no order affecting said rates, tolls, charges, schedules, regulations, or act complained of shall be entered by the Commission without a formal hearing.
(b) Commencing July 30, 2001, the Commission shall conduct rate investigations of all regulated utilities every five years and hold formal hearings as required under subsection (a) of this section.