Pub. Util. Code, § 6264

Every franchise granted pursuant to this chapter, except when a definite term therefor is specified in the ordinance granting it, is indeterminate, that is to say, every such franchise shall endure in full force and effect until, with the consent of the Public Utilities Commission, it is voluntarily surrendered or abandoned by its possessor, or until the State or some municipal or public corporation purchases by voluntary agreement or condemns and takes under the power of eminent domain, all property actually used and useful in the exercise of the franchise and situate within the territorial limits of the State, municipal, or public corporation purchasing or condemning such property, or until the franchise is forfeited for noncompliance with its terms by the possessor thereof.