I don't remember for certain, but six seems to ring a bell in my head for some reason. I remember they made a point in our training to say that the number for which we would be licensed was for total number of kids in home, such that kids already in the home (bio or adopted) would count. They also said that if a case worker placed a foster child in our home that made us go over our limit, we would be the ones held responsible, not the case worker (who may not even be aware of someone's licensing limits unless they make a point to check). That is, foster parents are ultimately responsible for making sure they don't accept a placement that puts them over the limit. That said, I seem to recall cases in which I saw special exceptions made and foster parents being allowed to take over the limit after having been in the system for a while. It wasn't ever for long-term stuff, but I am pretty sure it happened now and then.
Ah, just found the regs...
http://apps.leg.wa.gov/WAC/default.a...e=388-148-0525
The easiest way to get to this kind of stuff for WA is to go to
http://www.dshs.wa.gov/ca/fosterparents/index.asp. For regulations, you can click the button toward the top of the page that says, "Working With Laws and Rules."