Cal. Bus. & Prof. Code § 6732

It is unlawful for anyone other than a professional engineer licensed under this chapter to stamp or seal any plans, specifications, plats, reports, or other documents with the seal or stamp of a professional engineer, or in any manner, use the title “professional engineer,” “licensed engineer,” “registered engineer,” or “consulting engineer,” or any of the following branch titles: “agricultural engineer,” “chemical engineer,” “civil engineer,” “control system engineer,” “electrical engineer,” “fire protection engineer,” “industrial engineer,” “mechanical engineer,” “metallurgical engineer,” “nuclear engineer,” “petroleum engineer,” or “traffic engineer,” or any combination of these words and phrases or abbreviations thereof unless licensed under this chapter.