Washington
The statute in Washington state appear to be very simply and broadly stated.[19]

The law allows use of deadly force in the lawful defense of oneself, a family member, or any other person, when there is reasonable ground to prevent action(s) of the person slain to commit a felony or to do injury or harm, and there is imminent danger of such design being accomplished; or in the actual resistance of an attempt to commit a felony upon the slayer, on those in their presence, or upon or in a dwelling, or other place of abode, in which they are.

Washington state doesn’t have a specific Castle Doctrine law, but has no duty to retreat as precedent was set when the State Supreme Court found "that there is no duty to retreat when a person is assaulted in a place where he or she has a right to be