California Code, Public Utilities Code - PUC § 40128

The district shall take the necessary steps to obtain coverage for the district and its employees under Subchapter II of the federal Social Security Act, as amended,  1 and the related provisions of the Federal Insurance Contributions Act, as amended.  2

However, the district is not required to provide coverage under Subchapter II of the federal Social Security Act, as amended, for employees who are members of the Orange County Employees Retirement System. Notwithstanding Section 31557 of the Government Code, administrative and professional employees may be admitted to membership in the Orange County Employees Retirement System without making membership applicable to all employees of the district. The board, by resolution, shall determine which employees are employed in administrative and professional classifications.