Cal. Pub. Util. Code § 13575.6
Any party aggrieved by a final order issued by the board under Section 13575.5, after granting review of a hearing officer order, may obtain review of the order of the board in the superior court by filing in the court a petition for writ of mandate within 30 days following the issuance of the order by the board. Any party aggrieved by a final order of a hearing officer issued under Section 13575.5 for which the board denies review may obtain review of the order of the hearing officer in the superior court by filing in the court a petition of writ of mandate within 30 days following the denial of review by the board.
If no aggrieved party petitions for writ of mandate within the time provided by this section, an order of the board or a hearing officer shall not be subject to review by any court or agency, except that the board may grant review on its own motion of an order issued under Section 13575.5 after the expiration of the time limits set by that section.
Ca. Pub. Util. Code § 13575.6