California state law does not require that firearms are locked while in the home and not being used. It does require that prohibited persons not have access to your firearms. (Please check local city and county ordinances which may be different from state law and may require more.)
Penal Code 25100 PC is the California statute that defines the crime of criminal storage of a firearm. The law says a person cannot store a gun where a child may access it, and it is an offense if a child then gets it and injures either himself/herself or another person. A violation of the statute can result in a felony charge punishable by up to three years in state prison.
25100 PC states that “a person commits the crime of criminal storage of a firearm…if all of the following conditions are satisfied: The person keeps any firearm within any premises that are under the person’s custody or control. The person knows or reasonably should know that a child is likely to gain access to the firearm without the permission of the child’s parent or legal guardian. [And] the child obtains access to the firearm and thereby causes death or great bodily injury to the child or any other person.”
Home safes and trigger locks (pictured above) can be helpful in securing your firearms in the home. Car safes (pictured below) provide more security when leaving a firearm in an unmanned vehicle or while transporting. (Again, please check your local ordinances for the city and county as they vary across the state in regards to transportation and storage of firearms in vehicles)
For more information we highly recommend getting a copy of California Gun Laws that updates each year.