State law regulates the treatment of animals in a variety of contexts.  Animal cruelty statutes prohibit harming or killing animals in most situations and transporting or confining animals in an unsafe manner.  State law also requires dog breeding operations to meet requirements regarding space, sanitation, and safety.  Dog breeding operations may not have more than 50 adult, intact dogs at one time unless licensed as a commercial breeder by the United States Department of Agriculture (USDA) prior to January 1, 2010.

Certain categories of animal sales are regulated at the federal and state levels.  For example, federal and state laws regulate the sale of livestock and the sale of animals for use in research.  The retail or private sale of domesticated animals is generally not regulated at either the federal or state level; however, the state prohibits a live dog or cat from being named as collateral for a consumer lease or secured transaction. 

Some counties and cities impose regulations on the sale of animals intended for use as pets, such as imposing licensing requirements on retail pet stores and prohibiting the sale of animals in public places.  An "animal care and control agency" is a city or county animal control agency or authority authorized to enforce city or county ordinances regulating the care, control, licensing, or treatment of animals. 

A retail pet store may not sell or offer to sell any cat.  A retail pet store may not sell or offer to sell any dog unless the retail pet store:

• sold a dog prior to the effective date of the bill;
• only sells a dog at the location address identified on its business license as of the effective date of the bill;
• obtains any dog sold directly from a breeder licensed by the USDA that also has maintained compliance with Washington's dog breeding regulations for at least three years;
• obtains all inspection reports created by the USDA for the breeder within the previous three years and maintain the reports for five years; and
• prominently displays the full name and USDA license number of the breeder from which a dog was obtained on the cage or enclosure of any dog offered for sale and on any advertisement for the sale of a dog. 

 
A retail pet store is subject to a class 1 civil infraction for a first-time violation.  Subsequent violations are subject to a penalty of $500.  Each animal offered for sale constitutes a separate violation.  Any retail pet store with three or more violations is prohibited from selling or offering to sell any dogs.  Local animal care and control agencies are responsible for enforcement.
 
To exceed the limit of 50 adult, intact dogs at one time, dog breeding operations must have maintained a USDA commercial breeder license without interruption since January 1, 2010.