Cal. Pub. Res. Code § 3200

An owner or operator of a well or production facility shall designate an agent, giving his or her address, who resides in this state, to receive and accept service of all orders, notices, and processes of the supervisor or a court of law. Every person so appointing an agent shall, within five days after the termination of the agency, notify the supervisor, in writing, of the termination, and unless operations are discontinued, shall appoint a new agent.