Cal. Rev. & Tax. Code § 2781

If a taxpayer or agent for the taxpayer submits a payment indicated for application to a specific tax or tax installment and that tax or tax installment already has been paid, the county shall return the replicated payment to the tendering party within 60 days of the date the payment becomes final. For purposes of this section, “final” means the original payment that is not subject to chargeback, dishonor, or reversal. However, when a replicated payment is made of any tax or tax installment paid by the Controller to the county pursuant to Section 2514, the amount of the replicated payment shall be paid to the claimant on whose behalf the payment was made.