Cal. Government Code § 31641.4

(a) (1) Except as provided in paragraph (2), a member shall receive credit for employment in public service only for such service as the member is not entitled to receive a pension or retirement allowance from such public agency. The service for which the member elects to contribute and the fact that no pension or retirement allowance will accrue to such member by virtue of the member’s employment in the public agency shall be certified to by an officer of the public agency where the member rendered such public service or shall be established to the satisfaction of the board. (2) Nothing in this subdivision prohibits a member from receiving credit for a period of federal public service if federal law expressly permits the credit even though the member is already entitled to receive a pension or retirement allowance from that service. It is intended that this section be consistent with the holdings in Cantwell v. San Mateo County (1980) 631 F.2d 631. (b) Notwithstanding any other provision of law, a safety member who receives credit for prior employment in public service, the principal duties of which consisted of active law enforcement or active fire suppression, or active service in the armed services of the United States during time of war or national emergency, shall have the member’s pension or retirement allowance for this service calculated on the same basis as the calculation of the retirement allowance the member would receive as a safety member under Section 31664. (c) A safety member who entered the service as a peace officer prior to the establishment of the safety membership provisions in the member’s county shall be considered a safety member from the member’s initial hiring date, for the purposes of this section, notwithstanding any other provision of law.