California Code, Public Utilities Code - PUC § 125523

(a) A contract or agreement shall not be made with any labor organization, association, or group that denies membership on any basis listed in subdivision (a) of Section 12940 of the Government Code, as those bases are defined in Sections 12926 and 12926.1 of the Government Code. However, the organization may preclude from membership any individual who advocates the overthrow of the government by force or violence.

(b) The district shall not discriminate with regard to employment against any person on any basis listed in subdivision (a) of Section 12940 of the Government Code, as those bases are defined in Sections 12926 and 12926.1 of the Government Code, except as otherwise provided in Section 12940 of the Government Code.