California Code, Code of Civil Procedure - CCP § 708.550

(a) The judgment debtor may claim that all or a portion of the right to payment is exempt from enforcement of a money judgment by application to the court on noticed motion filed not later than three days before the date set for the hearing on the judgment creditor's application for an assignment order. The judgment debtor shall execute an affidavit in support of the application that includes all of the matters set forth in subdivision (b) of Section 703.520. Failure of the judgment debtor to make a claim of exemption is a waiver of the exemption.

(b) The notice of the motion shall be personally served on the judgment creditor not later than three days before the date set for the hearing.

(c) The court shall determine any claim of exemption made pursuant to this section at the hearing on issuance of the assignment order.