Existing law requires the Public Utilities Commission, if it determines that the rules, practices, equipment, appliances, facilities, or service of a public utility, or the methods of manufacture, distribution, transmission, storage, or supply used by the public utility, are unjust, unreasonable, unsafe, improper, inadequate, or insufficient, to determine and fix the rules, practices, equipment, appliances, facilities, service, or methods to be observed, furnished, constructed, enforced, or used.