Cal. PCC § 20682

(a) A district may purchase materials and supplies for the construction or completion of any building, structure, or improvements in the open market when the cost does not exceed twenty-five thousand dollars ($25,000).

(b) Contracts for materials and supplies for the construction or completion of any building, structure, or improvement, when the cost exceeds twenty-five thousand dollars ($25,000), shall be contracted for and let to the lowest responsible bidder after notice. If two or more bids are the same and the lowest, the district board may accept the one it chooses.

(c) The district shall publish a notice inviting bids for any contract for which competitive bidding is required at least one time in a newspaper of general circulation in the district at least one week before the time specified for receiving bids. The notice inviting bids shall set a date for opening the bids and distinctly state the materials and supplies to be purchased.

(d) If the general manager recommends and the board of directors determines that the publication of advertisements of the notice in trade journals and papers in lieu of publication pursuant to subdivision (c) will increase the number of business enterprises receiving that notice, the board of directors may by resolution declare that those notices shall be published in trade journals and papers at least 10 days prior to the time specified for receiving bids.

(e) At its discretion, the board of directors may reject any bids presented and readvertise.

(f) In the case of an emergency, the board of directors may act pursuant to Chapter 2.5 (commencing with Section 22050).

(g) As an alternate to the procedures required by this section, a district may rely on the Uniform Public Construction Cost Accounting Act, Chapter 2 (commencing with Section 22000) of Part 3 of Division 2.