California Code, Government Code - GOV § 53221

The legislative body of the local agency which establishes a pension trust plan pursuant to the provisions of this article may provide for waiver of membership by prospective employees in the case of newly hired employees who have obtained the age of 60 years of age.  Such legislative body may also provide that an employee shall at the end of the pay period in which he or she obtains the age of 70 automatically cease to be an employee of the agency which hired him.