Cal. Health & Safety Code § 18025.5

(a) Pursuant to the National Manufactured Housing Construction and Safety Standards Act of 1974 (42 U.S.C. Sec. 5401 et seq.), the department may assume responsibility for the enforcement of manufactured home and mobilehome construction and safety standards relating to any issue with respect to which a federal standard has been established. The department may adopt regulations to ensure acceptance by the Secretary of Housing and Urban Development of California’s plan for the administration and enforcement of federal manufactured home and mobilehome safety and construction standards.
(b) The department may conduct inspections and investigations that it determines may be necessary to secure enforcement of this part and regulations adopted pursuant to this part.
(c) Subdivision (b) shall not apply to the enforcement of Section 18027.3 unless the department determines that there is a compelling reason to exercise oversight in the inspection of recreational vehicles or park trailers at a factory, in which case the department may investigate the inspection, or conduct a department inspection, on recreational vehicles or park trailers at a factory and utilize any means necessary to collect a fee from the manufacturer for the cost of the department investigation or inspection.
(d) For the purposes of enforcement of this part and the related regulations, persons duly designated by the director of the department, upon presenting appropriate credentials to the owner, operator, or agent in charge, may do both of the following:
1. (1) Enter, at reasonable times and without advance notice, any factory, warehouse, sales lot, or establishment in which manufactured homes, mobilehomes, commercial coaches, or special purpose commercial coaches are manufactured, stored, held for sale, sold, or offered for sale, rent, or lease.
2. (2) Inspect, at reasonable times and within reasonable limits and in a reasonable manner, any factory, warehouse, sales lot, or establishment, and inspect the books, papers, records, and documents to ensure compliance with this part.