California Code, Labor Code - LAB § 1773.2

The body awarding any contract for public work, or otherwise undertaking any public work, shall specify in the call for bids for the contract, and in the bid specifications and in the contract itself, what the general rate of per diem wages is for each craft, classification, or type of worker needed to execute the contract.

In lieu of specifying the rate of wages in the call for bids, and in the bid specifications and in the contract itself, the awarding body may, in the call for bids, bid specifications, and contract, include a statement that copies of the prevailing rate of per diem wages are on file at its principal office, which shall be made available to any interested party on request.  The awarding body shall also cause a copy of the determination of the director of the prevailing rate of per diem wages to be posted at each job site.