Cal. Health & Safety Code § 19991.4

The department may provide by regulation for the qualification and disqualification of quality assurance agencies to perform inspections of factory-built housing manufacturers. Quality assurance agencies shall act on behalf and subject to the supervision of the department and shall exercise the powers of the department with respect to these inspections, as provided by regulations of the department. These regulations shall specifically provide for the absence of any conflict of interest between manufacturers and quality assurance agencies and for department oversight of the performance quality assurance agencies.