California Code, Welfare and Institutions Code - WIC § 15705.25

(a) Notice of the filing of a petition for an emergency order shall be given, in language as understandable by the endangered adult as reasonably possible, at least 24 hours prior to the hearing on the petition for emergency intervention.

(b) The court may waive the 24-hour notice requirement on a showing that immediate and reasonably foreseeable physical harm to the person or other persons will result from the 24-hour delay, and reasonable attempts have been made to give notice.  Notice of the final order of the court shall be given to each of the parties to the petition hearing.