The purchase of all supplies, equipment and materials, and the construction of facilities and works, when the expenditure required exceeds five thousand dollars ($5,000), shall be by contract let to the lowest responsible bidder. Notice requesting bids shall be published at least once in a newspaper of general circulation, which publication shall be made at least 10 days before bids are received. The board may reject any and all bids and readvertise in its discretion.
Ca. Pub. Cont. Code § 20271