Cal. Civ. Code § 8.01-130.01

A. If, in an action for unlawful detainer filed in general district court, (i) such action is dismissed and the 30-day period following such dismissal has passed or (ii) a voluntary nonsuit of such action is taken and the six-month period following such nonsuit has passed, provided that no order of possession has been entered in the case, the court shall, without further petition or hearing, enter an order requiring the expungement of the court records. The court shall not automatically expunge such records in an unlawful detainer action where a judgement is entered in favor of the defendant; however, such a defendant may file a petition, and the court shall, without a hearing, expunge such records in accordance with the provisions of subsection B.
B. For unlawful detainer actions commenced prior to July 1, 2024, for which the court still has records, if (i) such action was dismissed and the 30-day period following such dismissal has passed or (ii) a voluntary nonsuit of such action was taken and the six-month period following such nonsuit has passed, provided that no order of possession has been entered in the case, the defendant may file a petition on a form created by the Supreme Court in the general district court in which the underlying unlawful detainer action was filed requesting expungement of the court records relating to the unlawful detainer. The petition shall provide the date that the order of dismissal, entry of judgment in favor of the defendant, or nonsuit was entered, the address of the property that was the subject of the unlawful detainer action, and the name of the plaintiff in the unlawful detainer action.
Upon finding that the unlawful detainer action was dismissed and the 30-day period following such dismissal has passed or a nonsuit was taken and the six-month period following such nonsuit has passed, and no order of possession was entered, the court shall, without a hearing, enter an order requiring the expungement of the court records.