Cal. Unemployment Insurance Code § 1222

Within 30 days of service of any notice of assessment or denial of claim for refund or credit under Section 803, 821, or 991, or of any notice under Sections 704.1, 1035, 1055, 1127.5, 1131, 1142, 1143, 1144, 1180, 1184, 1733, and 1735, any employing unit or other person given the notice, or any employing unit affected by a granting or denial of a transfer of reserve account, may file a petition for review or reassessment with an administrative law judge. The administrative law judge may for good cause grant an additional 30 days for the filing of a petition. If a petition for reassessment is not filed within the 30-day period, or within the additional period granted by the administrative law judge, an assessment is final at the expiration of the period. If a petition for review of a termination of elective coverage under Section 704.1 is not filed within the 30-day period, or within the additional period granted by the administrative law judge, the termination is final at the expiration of the period. If the director fails to serve notice of his or her action within 60 days after a claim for refund or credit is filed, the person or employing unit may consider the claim denied and file a petition with an administrative law judge.