California Code, Public Contract Code - PCC § 20150.9

In its discretion, the county may reject any bids presented.  If, after the first invitation for bids, all bids are rejected, after reevaluating its cost estimates of the project, the county shall abandon the project or shall readvertise for bids in the manner prescribed by this article.  If after readvertising, the county rejects all bids presented, the county may proceed with the project by use of county personnel or may readvertise.  If two or more bids are the same and the lowest, the county may accept the one it chooses.  If no bids are received, the county may have the project done without further complying with this article.