Under legislation going into effect on January 1, store operators also will have to be able to provide records of origin for the animals or face a $500 penalty per animal.
The Pet Rescue and Adoption Act was introduced by assembly member Patrick O'Donnell and signed into law by California Governor Jerry Brown in October 2017
Under the law, individuals are still allowed to buy from private breeders, but stores are prohibited from doing so.
In a press release issued at the time, O'Donnell touted the law as an end to "puppy mills" and "kitten factories." California is the first state in the country to introduce such legislation.
O'Donnell called the law
a "big win for our four-legged friends" and also for taxpayers, who he said spent more than $250 million a year to house and euthanize shelter animals.
The act specifies that pet store operators can sell dogs, cats and rabbits only from a public animal control agency or shelter, society for the prevention of cruelty to animals shelter, humane society shelter, or rescue group in cooperation with an animal shelter.
It requires "each pet store to maintain records sufficient to document the source of each dog, cat, or rabbit the pet store sells or provides space for, for at least one year, and to post, in a conspicuous location on the cage or enclosure of each animal, a sign listing the name of the entity from which each dog, cat, or rabbit was obtained."
The stores also will be required to give public animal control agencies or shelters periodic access to those records.