Cal. Pub. Contract Code § 21003
The board shall, in open session, open and examine and declare the same. No proposal or bid shall be considered unless accompanied by such check or such bond in terms satisfactory to the board. The board may reject any and all proposals or bids should it deem it for the public good, and shall reject all proposals or bids other than the lowest regular proposal or bid of any responsible bidder, and may award the contract for said work to the lowest responsible bidder at the price named in his or her bid.
A notice of such award, attested by the clerk of the board of supervisors shall be transmitted to the successful bidder by mail by the clerk of the board of supervisors, and shall also be published and posted in a manner herein provided as to the notice inviting proposals or bids.
The check or bond accompanying such accepted proposal or bid shall be kept by the clerk of said board until the contract for doing said work, as hereinafter provided, has been entered into. Checks or bonds of unsuccessful bidders shall be returned by the clerk of said board. If said successful bidder fails, neglects or refuses for 15 days after being awarded the contract to execute the same, the certified check accompanying his bid, and the amount thereof shall be declared forfeited to the county, and may be collected by it and paid into the interest and sinking fund of the district, and any bond forfeited may be prosecuted, and the amount thereof collected and paid into said fund.
Before being entitled to a contract the bidder to whom the award thereof has been made must advance and pay to the clerk of the board of supervisors, the costs and expenses of publishing and posting the resolutions, notices and orders required under this act to be made, which have been made, given, posted, or published in the proceeding.
Ca. Pub. Cont. Code § 21003