Cal. Pub. Contract Code § 21004
Any person interested in the said proceeding may at any time within 10 days from the first publication of the notice of award file with the clerk of the board of supervisors a statement in writing specifying any particulars in which he or she may be aggrieved by the said proposed work and any and all objections he or she may have to the regularity or legality of the proceedings theretofore had or taken. The failure to file such written statement shall constitute and be a complete waiving of each and every objection to the proceedings theretofore had or taken and an estoppel and bar to any and all claims that the same or any portion thereof have been or are irregular, illegal, defective, erroneous, or faulty; provided, that the resolution of intention provided for in Section 6 of Chapter 354 of the Statutes of 1919 has been adopted and published.
Ca. Pub. Cont. Code § 21004