Public Contract Code § 21565

Except as otherwise provided in Article 121.1 (commencing with Section 21568) of this chapter, whenever any work is not to be done by the district itself by force account, and the amount involved shall be twenty-five thousand dollars ($25,000) or more, the board shall provide for the letting of contracts to the lowest responsible bidder, after publication of notices inviting bids, but subject to the right of the board to reject any and all proposals.