Cal. Public Contract Code § 20251

(a) (1) The purchase of all supplies, equipment, and materials, when the expenditure required exceeds seventy-five thousand dollars ($75,000), shall be by contract let, in the district’s discretion, either to the lowest responsible bidder or to a responsible bidder that submits a proposal that provides the best value to the district. (2) For purposes of this subdivision, “best value” means the overall combination of quality, price, and other elements of a proposal that, when considered together, provide the greatest overall benefit relative to the requirements described in the solicitation requirements. (b) For the purchase of supplies, equipment, or materials that exceeds five thousand dollars ($5,000), but does not exceed seventy-five thousand dollars ($75,000), the district shall obtain, to the extent practicable, a minimum of three written or oral quotes that permit the district to compare the prices and terms for the purchase. (c) The construction of facilities and works, when the expenditure required exceeds three thousand dollars ($3,000), shall be by contract let to the lowest responsible bidder. Notwithstanding the preceding sentence, the district may elect to have this construction be governed by Article 3 (commencing with Section 22030) of Chapter 2. (d) 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.