Cal. Public Contract Code § 10126

Notwithstanding the provisions of Section 10125, the estimate of cost may be approved by the director, which includes alternates contemplating additions to, or deletions from, the base bid, provided that all of the following requirements are met: (a) Estimates are made for each contingency and, in the aggregate, the alternates do not exceed 10 percent of the estimated cost for the project. (b) The available funds are at least sufficient to cover the filed estimate for the base project. (c) Whenever additive or deductive items are included in a bid, the bid solicitation shall specify which one of the following methods will be used to determine the lowest bid. In the absence of such a specification, only the method provided by paragraph (1) will be used: (1) The lowest bid shall be the lowest bid price on the base contract without consideration of the prices on the additive or deductive items. (2) The lowest bid shall be the lowest total of the bid prices on the base contract and those additive or deductive items that were specifically identified in the bid solicitation as being used for the purpose of determining the lowest bid price. (3) The lowest bid shall be the lowest total of the bid prices on the base contract and those additive or deductive items that, when taken in order from a specifically identified list of those items in the solicitation, and added to, or subtracted from, the base contract, are less than, or equal to, a funding amount publicly disclosed by the department before the first bid is opened. (4) The lowest bid shall be determined in a manner that prevents any information that would identify any of the bidders or proposed subcontractors or suppliers from being revealed to the public entity before the ranking of all bidders from lowest to highest has been determined. (d) The contract is awarded to the lowest bidder, as determined by the method prescribed in subdivision (c). (e) A responsible bidder who submitted the lowest bid as determined by this section shall be awarded the contract, if it is awarded. This section does not preclude the department from adding to or deducting from the contract any of the additive or deductive items after the lowest responsible bidder has been determined. (f) Nothing in this section shall preclude the prequalification of subcontractors.