Cal. Pub. Util. Code § 28896

All money received by any person as an annuity, pension, retirement allowance, disability payment, or death benefit from the retirement system, and all contributions and interest thereon returned to any member of the retirement system, whether in the actual possession of such person or deposited, loaned, or invested by him, is exempt from execution or any other process except to the extent permitted by Section 704.110 of the Code of Civil Procedure and is unassignable.