California Code, Code of Civil Procedure - CCP § 2031.300

(a) The party to whom the demand for inspection, copying, testing, or sampling is directed waives any objection to the demand, including one based on privilege or on the protection for work product under Chapter 4 (commencing with Section 2018.010). The court, on motion, may relieve that party from this waiver on its determination that both of the following conditions are satisfied:

(b) The party making the demand may move for an order compelling response to the demand.

(c) Except as provided in subdivision (d), the court shall impose a monetary sanction under Chapter 7 (commencing with Section 2023.010) against any party, person, or attorney who unsuccessfully makes or opposes a motion to compel a response to a demand for inspection, copying, testing, or sampling, unless it finds that the one subject to the sanction acted with substantial justification or that other circumstances make the imposition of the sanction unjust. If a party then fails to obey the order compelling a response, the court may make those orders that are just, including the imposition of an issue sanction, an evidence sanction, or a terminating sanction under Chapter 7 (commencing with Section 2023.010). In lieu of or in addition to this sanction, the court may impose a monetary sanction under Chapter 7 (commencing with Section 2023.010).