Cal. Health & Safety Code § 5020

At the time of entering into the contract the contractor shall execute, deliver, and file with the governing body a good and sufficient surety bond, in a sum not less than one-half the total amount payable by the terms of the contract, conditioned upon the payment by the contractor or his subcontractors, for any and all materials, provisions, provender, other supplies, or teams, or the use of implements or machinery used in, upon, or about the performance of the work.