California Code, Public Contract Code - PCC § 10160

The department may require from prospective bidders answers to questions contained in a standard form of questionnaire and financial statement including a complete statement of the prospective bidder's financial ability and experience in performing public works.  When completed, the questionnaire and financial statement shall be verified under oath by the bidder in the manner in which pleadings in civil actions are verified.

Whenever prequalification is required of any bidder on a contract, it shall be required for all prospective bidders to that contract.