California Code, Penal Code - PEN § 18265

(a) No firearm or other deadly weapon taken into custody pursuant to this division shall be held less than 48 hours.

(b) Except as provided in Section 18400, if a firearm or other deadly weapon is not retained for use as evidence related to criminal charges brought as a result of the domestic violence incident or is not retained because it was illegally possessed, the firearm or other deadly weapon shall be made available to the owner or person who was in lawful possession 48 hours after the seizure, or as soon thereafter as possible, but no later than five business days after the owner or person who was in lawful possession demonstrates compliance with Chapter 2 (commencing with Section 33850) of Division 11 of Title 4.

(c) In any civil action or proceeding for the return of any firearm, ammunition, or other deadly weapon seized by any state or local law enforcement agency and not returned within five business days after the initial seizure, except as provided in Section 18270, the court shall allow reasonable attorney's fees to the prevailing party.