California Code, Government Code - GOV § 29851

Upon the filing of the affidavit, the auditor shall issue and deliver to the legal owner or custodian a duplicate warrant for the full amount of the original warrant, or for any lesser amount still due if any portion of the amount for which the warrant was drawn has been paid, and the treasurer shall pay the duplicate in lieu of the original warrant.  If a warrant is lost or destroyed after it has been received by a bank with whom the treasurer has entered into a written agreement pursuant to Article 2 (commencing with Section 53630) of Chapter 4 of Part 1 of Division 2 of Title 5 for the deposit in that bank of moneys belonging to or in the custody of the treasurer, the treasurer may pay on a photocopy of the lost or destroyed warrant in lieu of the original warrant;  provided the bank agrees to indemnify and hold the county harmless from any loss incurred by reason of that payment.