Cal. Rev. & Tax. Code § 6561

Any person against whom a determination is made under Article 2 (commencing with Section 6481) or 3 (commencing with Section 6511) or any person directly interested may petition for a redetermination within 30 days after service upon the person of notice thereof. If a petition for redetermination is not filed within the 30-day period, the determination becomes final at the expiration of that period.