Cal. Pub. Cont. Code § 20804

The notice inviting bids shall set a date for the opening of bids. The first publication or posting of the notice shall be at least 10 days before the date of opening the bids. Notice shall be published at least twice, not less than five days apart, in a newspaper of general circulation, circulated within the district, or if there is none, it shall be posted in at least three public places in the district that have been designated by resolution as the places for posting public notices. The notice shall distinctly state the project to be done.