Cal. Rev. & Tax. Code § 2921.5
Taxes, penalties, and costs on unsecured property, as defined in subdivision (b) of Section 134, shall be transferred from the "secured roll" to the "unsecured roll" of the corresponding year by the county auditor on order of the board of supervisors with the written consent of the county legal advisor pursuant to Article 5 (commencing with Section 5081) of Chapter 4 of Part 9 at the same time the taxes are canceled on the property, and shall be collected in the same manner as other delinquent taxes on the "unsecured roll." Amounts transferred pursuant to this section continue to be subject to delinquent penalties until the amounts are paid and are collectible from either the person from whom the property was acquired or the public entity that acquired the property.
Ca. Rev. and Tax. Code § 2921.5