California Code, Government Code - GOV § 8593.8

(a)(1) A county, including a city and county, may enter into an agreement with an adjacent county, upon the request of the adjacent county, for purposes of permitting the adjacent county to borrow, for compensation, the county's emergency management and transportation services in the event of an emergency that requires the evacuation and relocation of the access and functional needs population in the adjacent county. The services to be provided under an agreement entered into pursuant to this section shall be available 24 hours per day, seven days per week.

(2) For purposes of this section, “adjacent county” means a county within the same or a contiguous mutual aid region or regions, as defined in Section 8559.