Rules of the Road: How do you register a homemade travel trailer?


Question: I’ve been wanting to get a teardrop trailer but they’ve gotten really hard to find this year, with everyone deciding that the middle of a pandemic is a good time for more outdoor activities. If I can’t find a trailer I was thinking about building one. If I do that, how do I get it registered?

Answer: Are you a “letter of the law” type, or do you exist happily in gray areas? How you answer that might determine which of the following steps you adhere to in your trailer building process. To be clear, I’m not suggesting that you disregard the rules or skip legal requirements. It’s just that when you’re building your own camping trailer there’s a step that’s not required, but you might regret skipping it later.

Of all the steps in the building process, getting it licensed will probably be the last one before putting it to use. But to make the project go smoothly, I’ll suggest that you plan for that step first. You’ll be working with at least two, possibly three, state agencies, and understanding the process will certainly make things go smoother.

The Washington State Patrol (WSP) is responsible for inspecting homebuilt trailers. To succeed with your inspection you’ll need to bring a few things with you. Start by getting a WSP inspection request form from the department of licensing or a licensing agent. Bring the completed form to your WSP inspection (scheduled in advance) along with photo ID, a weight slip (you’ll have to take your trailer to a scale) and receipts for every major component you purchased for your trailer build. I couldn’t find a definition of “major component” but I’ll guess that if your trailer doesn’t work without it, you should probably keep a receipt.

Your receipts are required to show that all the components you built with are legally obtained. WSP wouldn’t want to license a trailer built on a stolen axle (or any other ill-acquired components). The inspection also serves to make sure the trailer meets the requirements to be road legal. This includes things like brake lights, turn signals, fenders and any other required safety features.

At the beginning of this I mentioned a gray area. Those aren’t my words; they’re from the person I spoke with at the Department of Labor and Industries (L&I). Washington law requires that any recreational vehicle built for sale or lease in Washington have an insignia on the RV. This is a label showing that L&I has inspected it. If you were buying an RV you’d want to know that things like the plumbing and wiring were done properly. The insignia is how you know your RV’s design has been approved. If you go this route, you’ll need to plan ahead, submit your plans to L&I before you build, and get inspections as needed during the building process.

You aren’t required to get an insignia for your own homebuilt RV that you plan to keep. However if you ever wanted to sell it in the state, well, the law states that any person selling an RV that doesn’t meet the requirements in the law is guilty of a misdemeanor, so there’s that.

I spoke with a WSP vehicle inspector who said that most of homebuilt RV trailers she’s inspected don’t have the insignia from L&I. She wasn’t willing to speculate on how things worked out for the owners of those trailers when they decided to sell them.

Regardless of how you decide to proceed, remember that what you’re building needs to be not only legal, but also safe on the road. You’re building something that has to tow without flailing behind you and can withstand highway-speed winds. Trailer engineering is beyond the scope of this column, but make sure you understand things like tongue weight, hitch ratings and where to position your axle. Once you’ve got it safely designed, built and registered, have fun camping.

Doug Dahl is a manager with the Washington Traffic Safety Commission, Region 11 and publishes


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