California Code, Public Utilities Code - PUC § 468

(a) For purposes of this section, “expense incurred by a public utility in assisting or deterring union organizing” means costs incurred in communicating with employees, or employees of the public utility's contractors, in an effort to persuade them to join or support, or to not join or support, a labor organization.

(b) Any expense incurred by a public utility in assisting or deterring union organizing shall not be recoverable either directly or indirectly in the public utility's rates and shall be borne exclusively by the shareholders of the public utility.