Cal. Pub. Util. Code § 7931

(a) This chapter is applicable to telephone corporations, including resellers, and to paging companies, hereafter referred to as providers.
(b) For purposes of this chapter, “coordinator” means the “coordinator for California area code relief” as designated by the North American Numbering Council.
(c) Whenever the coordinator and providers evaluate the potential boundaries of a new area code, they shall consider rate area boundaries, municipal boundaries, communities of interest, and other appropriate criteria.
(d) When the coordinator determines the need to establish a new area code, at least 30 months prior to the projected opening of the new area code, the coordinator shall provide written notice to the commission regarding the need to establish the new area code.
(e) From the date the written notice required by subdivision (d) is received by the commission all of the following shall be done:
1. (1) Within three months all providers shall notify all affected customers in writing of the need to establish a new area code. Nothing in this paragraph requires a customer to receive in one bill more than one notice for each billed number.
2. (2) Within nine months the coordinator and the commission staff shall notify representatives of local jurisdictions and the public in affected geographic areas, and, at the discretion of the commission, may conduct one or more meetings both for representatives of local jurisdictions and for members of the public in affected geographic areas to inform them of the proposed area code relief options and of measures that may be taken to mitigate any potential disruptions, and to afford them the opportunity to discuss the potential impact of the proposed options.
3. (3) Within 11 months the coordinator shall file the results of the area code relief planning process with the commission requesting commission approval to implement a plan. Anyone may contest the results of the area code planning process by filing a written protest with the commission not later than 60 days after the results have been filed with the commission.
(f) Unless the commission determines otherwise, at least 12 months prior to the date adopted by the commission for opening the new area code, all of the following shall be done:
1. (1) The coordinator shall notify the general public of the specific geographic area to be included in both the old and new area codes. The notice shall include the schedule for any transitional dialing periods required by Section 7932.
2. (2) Each telephone provider serving the specific geographic area included in the existing area code shall give written notice to all its affected customers about the specific geographic area that will be included in the new area code. The notice shall include the schedule for any transitional dialing periods required by Section 7932, and the prefixes that will be contained in the new area code. Nothing in this paragraph requires a customer to receive in one bill more than one notice for each billed telephone number.
(g) Within three months prior to the adopted date for opening the new area code, each provider serving the existing area code shall give written notice to its affected customers of the specific geographic boundaries of the new area code. The notice shall include the schedule for any transitional periods required by Section 7932, and the prefixes that will be contained in the new area code. Nothing in this paragraph requires a customer to receive in one bill more than one notice for each billed number.