Washington Revised Code Title 46. Motor Vehicles § 46.16A.440. Private use, single-axle trailers--Reduced license fee

(1) The trailer must be operated upon public highways;

(2) The vehicle license fee must be collected annually for each registration year or fraction of a registration year; and

(3) The trailer must be operated for personal use of the owner and not held for rental to the public or used in any commercial or business endeavor.