Cal. Lab. Code § 3725
If an employer desires to contest a penalty assessment order, the employer shall file with the director a written request for a hearing within 15 days after service of the order. Upon receipt of the request, the director shall set the matter for a hearing within 30 days thereafter and shall notify the employer of the time and place of the hearing by mail at least 10 days prior to the date of the hearing. The decision of the director shall consist of a notice of findings and findings which shall be served on all parties to the hearing by registered or certified mail within 15 days after the hearing. Any amount found due by the director as a result of a hearing shall become due and payable 45 days after notice of the findings and written findings have been mailed by registered or certified mail to the party assessed. A writ of mandate may be taken from these findings to the appropriate superior court upon the execution by the party assessed of a bond to the state in double the amount found due and ordered paid by the director, as long as the party agrees to pay any judgment and costs rendered against the party for the assessment. The writ shall be taken within 45 days after mailing the notice of findings and findings.
Ca. Lab. Code § 3725