If you want to be able to pull your house down a highway without a special permit, it must conform to certain size limits. In most U.S. states this maximum size is 13.5-feet tall, 8.5-feet wide, and40-feet long – 65-feet maximum including the tow vehicle.
Washington State Patrol Limitations:
53 Feet long
102inches wide or 8foot 6inches max width
20,000 pounds on one axle
34,000 pounds on tandem axles
RCW 43.22.350: If you build a camp trailer and want to license it as a Recreational Vehicle
(RV) camp trailer, at the time of inspection you must present a completed Labor & Industries
(L&I) RV inspection with the L&I inspection insignia applied to your camp trailer. Please
contact your local L&I office for information on their inspection process. In addition to the L&I
inspection, you must also present valid release documents for the trailer and/or parts used.