Cal. Pub. Res. Code § 7531

All payments shall be made by the purchaser to the county treasurer of the county in which the land is situated. The treasurer shall receive the amounts to be paid including the fee for the certificate of purchase, if any. The treasurer shall endorse upon the certificate of purchase the amount of all payments and shall direct the purchaser to take the certificate of purchase, so endorsed, to the county auditor who shall charge the treasurer with the amount received and make his check upon the endorsed receipt.