Cal. Civ. Code § 1834.5

(a) Notwithstanding any other provision of law, whenever an animal is delivered to a veterinarian, dog kennel, cat kennel, pet-grooming parlor, animal hospital, or any other animal care facility pursuant to a written or oral agreement entered into after the effective date of this section, and the owner of the animal does not pick up the animal within 14 calendar days after the day the animal was initially due to be picked up, the animal shall be deemed to be abandoned. The person into whose custody the animal was placed for care shall first try for a period of not less than 10 days to find a new owner for the animal or turn the animal over to a public animal control agency or shelter, society for the prevention of cruelty to animals shelter, humane society shelter, or nonprofit animal rescue group, provided that the shelter or rescue group has been contacted and has agreed to take the animal. If unable to place the animal with a new owner, shelter, or rescue group, the animal care facility may have the abandoned animal euthanized.

(b) If an animal so abandoned was left with a veterinarian or with a facility that has a veterinarian, and a new owner cannot be found pursuant to this section, the veterinarian may euthanize the animal.

(d) There shall be a notice posted in a conspicuous place, or in conspicuous type in a written receipt given, to warn a person depositing an animal at an animal care facility of the provisions of this section.