Wash. Rev. Code § 43.22.470
The department shall have the authority to delegate all or part of its duties of inspection to a local enforcement agency or a qualified inspection agency.
Qualified inspection agencies shall be objective, competent, and independent from the companies responsible for the work being inspected. The qualified inspection agency will disclose to the department any conflict of interest so that objectivity may be confirmed. Qualified inspection agencies shall have adequate equipment to perform the required inspections and shall employ experienced personnel with appropriate certifications and knowledge for the inspections being performed. Certification by the international code council will be recognized as meeting this last requirement.
RCW 43.22.470