Washington Revised Code Title 18. Businesses and Professions § 18.210.160. Prohibited practices--Penalty

On or after July 1, 2003, it is a gross misdemeanor for any person, not otherwise exempt from the requirements of this chapter, to: (1) Perform on-site wastewater treatment systems design services without a license; (2) purport to be qualified to perform those services without having been issued a license under this chapter; (3) attempt to use the license or seal of another; (4) attempt to use a revoked or suspended license; or (5) attempt to use false or fraudulent credentials. In addition, action may be taken under RCW 18.235.150.