Cal. Ins. Code § 6048

Except as provided in Section 6041 such insurer shall insure only property within the limits of the county wherein it is organized, or in a county next adjoining the county of organization. In the event that no such insurer may, under the provisions of the preceding sentence, insure property in a county contiguous to the said next adjoining county, then such insurer may also insure property in the said contiguous county.