California Code, Public Utilities Code - PUC § 453

(a) No public utility shall, as to rates, charges, service, facilities, or in any other respect, make or grant any preference or advantage to any corporation or person or subject any corporation or person to any prejudice or disadvantage.

(b) No public utility shall prejudice, disadvantage, or require different rates or deposit amounts from a person because of ancestry, medical condition, marital status or change in marital status, occupation, or any characteristic listed or defined in Section 11135 of the Government Code. A person who has exhausted all administrative remedies with the commission may institute a suit for injunctive relief and reasonable attorney's fees in cases of an alleged violation of this subdivision. If successful in litigation, the prevailing party shall be awarded attorney's fees.

(c) No public utility shall establish or maintain any unreasonable difference as to rates, charges, service, facilities, or in any other respect, either as between localities or as between classes of service.

(d) No public utility shall include with any bill for services or commodities furnished any customer or subscriber any advertising or literature designed or intended (1) to promote the passage or defeat of a measure appearing on the ballot at any election whether local, statewide, or national, (2) to promote or defeat any candidate for nomination or election to any public office, (3) to promote or defeat the appointment of any person to any administrative or executive position in federal, state, or local government, or (4) to promote or defeat any change in federal, state, or local legislation or regulations.

(e) The commission may determine any question of fact arising under this section.