Cal. Health & Safety Code § 16017

During construction or alteration of an essential services building, the building owner shall provide for, and the local enforcement agency shall require, competent, adequate, and detailed inspection by a qualified inspector. To be qualified, inspectors shall have an adequate level of expertise and experience in the subject matter for which they have responsibilities for inspection as prescribed by this section. Qualification shall include current certification by the International Conference of Building Officials; or qualifications as an inspector meeting the requirements of subdivision (a) of Section 305 and subdivision (b) of Section 306 of, the 1982 Edition of the Uniform Building Code. Additionally, the architect, civil engineer, or structural engineer responsible for designing the essential services facility is qualified to inspect construction of the facility.