Cal. Rev. & Tax. Code § 6487.05

(a) Notwithstanding Section 6487, the period during which a deficiency determination may be served to a qualifying retailer is limited to three years after the last day of the calendar month following the quarterly period for which the amount is proposed to be determined. For purposes of this section, a “qualifying retailer” is a retailer that meets all of the following conditions:
1. (1) The retailer is located outside this state, and has not previously registered with the department.
2. (2) The retailer is engaged in business in this state, as defined in Section 6203.
3. (3) The retailer voluntarily registers with the department.
4. (4) The retailer has not been previously contacted by the department or its agents regarding the provisions of Section 6203.
5. (5) As determined by the department, the retailer’s failure to file a return or failure to report or pay the tax or amount due required by law was due to reasonable cause and was not a result of negligence or intentional disregard of the law, or because of fraud or an intent to evade the provisions of this part.
(b) If the department or its designee finds that the retailer’s failure to make a timely return or payment is due to reasonable cause and circumstances beyond the retailer’s control, and occurred notwithstanding the exercise of ordinary care and the absence of willful neglect, the retailer shall be relieved of the penalties imposed pursuant to this part. Any retailer seeking relief of penalty shall file a statement under penalty of perjury setting forth the facts upon which they base their claim for relief.