Cal. Pub. Util. Code § 102222
(a) Except as provided in subdivision (b), contracts for the purchase of supplies, equipment, and materials in excess of one hundred twenty-five thousand dollars ($125,000) shall be by contract let to the lowest responsible bidder or, in the district’s discretion, to the responsible bidder that submitted a proposal that provides the best value, as defined in paragraph (1), to the district on the basis of the factors identified in the solicitation.