California Code, Public Utilities Code - PUC § 2893

(a) The commission shall, by rule or order, require that every telephone call identification service offered in this state by a telephone corporation, or by any other person or corporation that makes use of the facilities of a telephone corporation, shall allow a caller to withhold display of the caller's telephone number, on an individual basis, from the telephone instrument of the individual receiving the telephone call placed by the caller.However a caller shall not be allowed to withhold the display of the caller's business telephone number when that number is being used for telemarketing purposes.

(b) There shall be no charge to the caller who requests that his or her telephone number be withheld from the recipient of any call placed by the caller.

(c) The commission shall direct every telephone corporation to notify its subscribers that their calls may be identified to a called party either:

(d) This section does not apply to any of the following:

(e) Until the market for local telephone service is competitive, a telephone corporation shall not charge any subscriber for having an unlisted or unpublished telephone number. However, nothing in this subdivision shall be interpreted by the commission to reduce the revenues of telephone corporations. Any actions of the commission pursuant to this subdivision shall be implemented on a competitively neutral basis. This charge shall not be eliminated prior to the effective date upon which offsetting rates are implemented by the commission.