Cal. Pub. Cont. Code § 20440

The work, in all cases, shall be done under the direction and to the satisfaction of the superintendent of streets and the materials used shall comply with the specifications and be to the satisfaction of the superintendent of streets and all contracts made therefor shall contain a provision to that effect unless the legislative body by resolution adopted within 10 days after the passage of the resolution ordering the work directs that the work shall be done under the direction of the engineer and the materials used shall comply with the specifications and be to the satisfaction of the engineer, instead of the superintendent of streets, and in such case the contract shall contain a provision to that effect.