Cal. Gov. Code § 31645
Except as provided in Sections 31641.5 or 31648 credit for prior service, whether interrupted or not, shall be granted to each person who has rendered such service as defined in or pursuant to this chapter, and who has become a member of the retirement system within one year after it becomes operative or at any time prior to October 1, 1953, whichever is the later, or within six months after discharge from military service.
One who performed service otherwise qualifying for credit under this section, who re-entered county employment subsequent to September 1, 1953 and prior to December 31, 1953, shall receive credit for such service, subject to Section 31648, provided such person is employed, as of the effective date of this section, in a position for which service credit is given under this article.
Ca. Gov. Code § 31645