Cal. Pub. Util. Code § 30404
As an alternative method of providing a retirement system the board may contract with the Board of Administration of the Public Employees' Retirement System and enter all or any portion of its employees under such system pursuant to law and under the terms and conditions of such contract, or may contract with the Board of Administration of the Public Employees' Retirement System for reciprocal benefits between the Public Employees' System, or a city, or city and county, or any other public agency contracting with the Public Employees' Retirement System and the district's retirement system as authorized by Section 20042 of the Government Code, and may perform all acts necessary or convenient to provide for such reciprocal benefits.
Ca. Pub. Util. Code § 30404