California Code, Government Code - GOV § 53118

The Legislature declares that a major purpose in enacting this article is to eliminate instances in which a responding emergency service refuses to render aid to the requester because the requester is outside of the jurisdictional boundaries of the emergency service.  A public safety agency which receives a request through the system for emergency services outside its jurisdictional boundaries shall transmit the request to the proper public safety answering point or public safety agency utilizing the methods described in Sections 53103 to 53105, inclusive.  In the event an emergency unit is dispatched in response to a request through the system, such unit shall render its services to the requesting party without regard to whether the unit is operating outside its normal jurisdictional boundaries until properly relieved by the public safety agency responsible for that geographical area.  Public agencies within a single system and public agencies in different systems but whose jurisdictional boundaries are contiguous are authorized to enter into joint powers agreements or any other form of written cooperative agreement to implement this requirement.  These agreements may further provide for a public safety agency to render aid outside its normal jurisdictional boundaries when need arises on a day-to-day basis.