Wash. Rev. Code § 25.15.048
(1) No limited liability company formed under this chapter may render professional services except through a person or persons who are duly licensed or otherwise legally authorized to render such professional services within this state. However, this chapter does not:
(2) Persons engaged in a profession and otherwise meeting the requirements of this chapter may operate under this chapter as a professional limited liability company so long as each member personally engaged in the practice of the profession in this state is duly licensed or otherwise legally authorized to practice the profession in this state and:
[ 2015 c 188 s 14.]