California Code, Business and Professions Code - BPC § 6704

(a) In order to safeguard life, health, property, and public welfare, no person shall practice civil, electrical, or mechanical engineering unless appropriately licensed or specifically exempted from licensure under this chapter, and only persons licensed under this chapter shall be entitled to take and use the titles “consulting engineer,” “professional engineer,” or “registered engineer,” or any combination of those titles or abbreviations thereof, and according to licensure with the board the engineering branch titles specified in Section 6732, or the authority titles specified in Sections 6736 and 6736.1, or the title “engineer-in-training.”

(b) The provisions of this section shall not prevent the use of the title “consulting engineer” by a person who has qualified for and maintained exemption for using that title under the provisions of Section 6732.1, or by a person licensed as a photogrammetric surveyor.