Cal. Pub. Cont. Code § 20302

If after rejecting bids the board determines and declares by two-thirds vote of all its members that in its opinion, the supplies, equipment, and materials may be purchased at a lower price in the open market, the board may proceed to purchase the supplies, equipment, and materials in the open market, if the open market purchase price is lower than the rejected bid, without further observance of the provisions requiring contracts, bids, or notice.