Are RVs Built to a Design Code?

Are RVs built to a code? Yes, they are.

Some of you are scoffing right now, wondering how your piddly bunk bed ladder could possibly pass an inspection.

Well, actually, that’s not part of the code. RV construction code, you see, isn’t analogous to the IRC that we all know and love. RVs aren’t like houses or cars. Regulations are different, and the Recreational Vehicle Industry Association (RVIA) has worked hard to keep things that way. That’s one reason there are so many RV manufacturers (unlike the automobile industry).

I used to work as an RV design engineer before I took up self-employment as an RV technician. Let’s look at the code requirements and regulations from a federal, state, local, and industry perspective.

Handbook showing the RVIA Guide to the NFPA 1192 standard

Federal Laws about RV Code & Design

Yes, there are federal laws that govern recreational vehicles. These laws are part of the Federal Motor Vehicle Safety Standards (FMVSS), which is part 571 of the US 49 Code of Federal Regulations (CFR). Most of these laws apply to all motor vehicles, not just RVs. Unlike commercial cargo vehicles, RVs are not generally subject to additional regulations from the Federal Motor Carrier Safety Administration (FMCSA), which are mostly compiled in Parts 300-399 of 49 CFR.

It’s a healthy helping of alphabet soup, I know. But cutting through the nine-layer cake of bureaucracy that is the federal government takes some time. For instance, the National Highway Traffic Safety Administration (NHTSA) is in charge of motor vehicle (including RV) safety recalls. NHTSA is part of the Department of Transportation (DOT); it is a nested entity within. You can see the other sub-agencies within DOT, but NHTSA is the one that issues the road safety regulations that most RV manufacturers are subject to. 

So most federal regulations that pertain to RVs are stuffed with 49 CFR 571. These rules govern lighting and reflectors, tire size and type, brakes, windshields and glazing, GVWR and cargo capacity calculations, towing, crash protection, etc.

VIN requirements are set by NHTSA. You can decode your VIN by visiting this NHTSA link here.

RVs are not generally subject to crash testing. Regulations do vary between towable RVs, which are not allowed occupants in transit, and motorhomes, which obviously are allowed occupants while in transit. However, generally, the RV “house,” the section of the RV built by the final-stage manufacturer, is not subject to actual crash testing. Yes, this includes Class A coaches! 

There are federal laws that govern GVWR, tongue weight, cargo capacity, and other weight capacities. I’ve answered some of these questions in these two articles: How Is the GVWR of Your RV Calculated?, Here’s Why Your GVWR Is Greater than Your GAWR, and Let’s Talk Tongue Weight: How Much Is Too Much? 

The regulations don’t offer instructions on how to design an RV chassis. By and large, RV manufacturers (or the first-stage chassis manufacturer) have the freedom to design the frame, suspension, etc. how they please. This is true of most motor vehicles, by the way, not just RVs. No government party is checking welds or doing FEA analysis. Federal law is more concerned about the tires, brakes, axle capacity, and other safety-critical elements.  

State Laws about RV Code & Design

Yes, there are state laws that govern recreational vehicles. Because the federal government oversees most of the highway safety elements, state laws typically govern the use and maximum size of RVs.

State law generally governs maximum RV width and length. Yes, these rules can vary widely by state! There are many RV websites that list of the maximum width and length of an RV by state for your convenience. Here’s a list from the website 5th Wheel Street.

For instance, some states allow wide-body RVs up to 102”, and others restrict maximum RV width to 96” except on major highways and Interstates. 

Height and length are also restricted. Most states have a maximum motor vehicle height of 13.5 feet without requiring an oversize/over-height permit (and usually a police escort). Other states, particularly out west, may have a maximum height of 14 feet; other states, especially back east, may limit the maximum motor vehicle height to only 13 feet, especially when off-Interstate and major highways. RV- and truck-specific GPS’s can map out specific routes to avoid low bridge overpasses and other road obstacles.

The RVIA lobbies all states to adopt similar standards so that RVers can easily travel between states. “The RV Industry Association supports a maximum length of 45 feet for a motorhome, a maximum allowable width of 102 inches plus up to six inches additional for appurtenances for all RVs and a maximum RV combination length of 65 feet.”

State law places additional restrictions on road safety. For instance, states have different laws about when brakes are required on trailers. Some states require brakes on all highway-approved trailers; some, only if the trailer is over 3,000 lbs GVWR. 

State law controls RV registration, insurance requirements, driver’s licensing, residency, etc. You’ll have to contact your state DMV to learn your local rules. Again, many RV blogs/websites track these requirements for your convenience. Here’s a list showing RV driver’s license rules by state, and Progressive maintains a table of RV insurance requirements by state. You can also find tables showing RV lemon laws by state, double towing laws by state, firearm rules by state, seat belt laws by state, 5th wheel occupancy by state, etc.

State law works in tandem with federal law to govern domiciling. There are IRS laws that govern what you can call a domicile, what’s a primary vs secondary residence, etc. But state laws do govern who can call themselves a resident of the state, even if you’re traveling in an RV full-time. For those reasons, the most popular states in which to claim RV domicile are South Dakota, Texas, and Florida. 

A few states require plan approval for RVs to be sold within that state by a licensed dealer. (And yes, most states restrict the sale of new RVs to licensed dealerships only, which have their own quite extensive application and bond requirements.) Many states accept RVIA membership as a stamp of approval for conformance with state RV standards, but a few states go above and beyond the call. Washington and Nebraska are the top two, but Washington, in particular, is rather a nightmare. The Washington Department of Labor and Industries is chronically backlogged, and most of their requirements simply mimic federal FMVSS and RVIA industry requirements. 

Local Laws about RV Code & Design

To my knowledge, municipalities, counties, and other governments within the state don’t usually have their own RV regulations –

– with one notable, rather large exception: residency. Counties are usually in charge of their own zoning laws, and most counties restrict the type and size of residency based on zoning classification. Most places do not allow RVs to be used as full-time residential dwellings unless they are a part of an authorized RV campground. Some will make exceptions if the RV is parked on an approved pad, with an approved electrical, water and sewer hookup, but for the most part, counties don’t like RVs being used as homes. (I suspect the lack of property taxes would have something to do with that). 

Industry Regulations About RV Code & Design

Yes, there are industry regulations that govern RV code and design –

But that is where things get interesting. Because these regulations are developed and issued by Standards Developing Organizations (SDOs) like ANSI, but who adopts them? Who enforces them?

Enter: The Recreational Vehicle Industry Association (RVIA), the godfather of the American RV industry representing 95%+ of all RVs manufactured and sold in this country.

Here are some excerpts from my article, What’s Up With That RVIA Sticker? 

The RVIA is primarily a trade organization. Yes, it also runs a compliance program, which is why there’s a sticker on your camper, but the true purpose of RVIA is to lobby and advocate on behalf of the industry.

  • RVIA sponsors the Go RVing annual marketing campaign, which drives billions in business to the RV industry.
  • RVIA maintains a library of educational and marketing materials available to industry insiders like marketers, campground owners, dealerships, etc.
  • RVIA lobbies policy-makers in state and national government. The Association adopts formal stances on contested issues such as trade tariffs, lemon laws, highway length restrictions, driver’s licenses, etc. These policies are promoted, in part, through the House and Senate RV Caucuses on Capitol Hill. 

The RVIA is mostly run by industry giants. The Board of Directors has celebrities like Forest River, Thor, Airxcel, Thetford, Onan/Cummins, Winnebago, KOA, Patrick Industries, Rev Group, Wesco Distribution, Lippert, Freightliner, etc. There’s hardly a component in your RV that wasn’t made by, assembled by, or distributed by one of those companies!

With that said, there are smaller voices as well, such as Aliner and Carefree of Colorado. And the voices rotate every few years. So there’s a good mix of manufacturers, OEMs, distributors, and campgrounds.

The RVIA mandates its members conform to certain standards, such as the following:

  • NFPA 1192 Standard for RVs: This standard covers the fuel systems and equipment, fire and life safety provisions, plumbing systems, and vehicular requirements for all RVs: motorhomes, towables, and truck campers.
  • National Electrical Code (NEC): The provisions of Article 551 cover the RV requirements for 120V/240V electrical systems. The provisions of Article 552 cover the Park Model RV requirements for 120V/240V electrical systems.
  • ANSI A119.5 Park Model RV Standard: This standard covers the fuel systems and equipment, health, fire and life safety provisions, plumbing systems, and construction requirements.
  • ANSI/RVIA Low Voltage Systems in Conversion and RVs Standard: This standard covers Low-Voltage (LV) electrical systems and devices up to 60 volts nominal or less.

RVIA also requires RV manufacturers to install appliances in accordance with their certified listing and manufacturer’s instructions. So your manufacturer can’t decide they can install a furnace any which way they want; they have to follow the OEM’s rules.

  • These standards are primarily concerned with electricity, propane (LP) distribution, freshwater supply, wastewater drain and venting, and fire and life safety. Unlike the International Residential Code for houses, for instance, the standards don’t say much about how the body or chassis of an RV should be constructed.
  • Most of these standards are similar to what’s required for your house or commercial building, with allowances made for the peculiar nature of an RV. An RV engineer isn’t allowed to hide any PEX plumbing inside of a laminated wall, for instance.

The RVIA is not a Standards Developing Organization (SDO). It can’t issue its own laws or regulations; it can only adopt standards from other bodies like the NFPA. 

The RVIA isn’t a dealership organization. Dealers have their own group: the RVDA, although there is a pretty close relationship between the two. 

The RVIA isn’t a government agency. You don’t get voted into office; you get hired for a job. Everyone who works for the RVIA is an employee, not a public official.

The RVIA doesn’t handle recalls. That’s the jurisdiction of the National Highway Traffic Safety Administration (NHTSA). (And fun fact, every RV manufacturer is required by law to state that in their Owner’s Manual!) Anything that isn’t within the purview of an NHTSA safety recall is usually publicized as a service bulletin issued by the manufacturer.

The RVIA isn’t a mandatory association. It’s opt-in only. And if you can’t pass muster, or you fail the inspection process, you’ll get booted out.

Theoretically, there’s no law in most states that says a manufacturer must be a member of RVIA. In fact, many smaller truck camper manufacturers and custom RV builders aren’t interested in membership.

However, in reality, that’s not wholly accurate. Each state may have its own laws about RV safety, but as of 2023, 49 states (except Washington) accept the RVIA sticker as proof of conformance. Without the sticker, you have to prove everything on your own. 

The RVIA isn’t a quality control program. This is where things get tricky, and a lot of RV buyers get confused because the RVIA does insist that a QC program must exist.

You see, as a member of RVIA, a manufacturer must abide by several hundred rules and regulations, embodied in adopted standards. But the RVIA isn’t “in charge” of the certification. Rather, a manufacturer “self-certifies,” and a trained RVIA inspector audits each assembly line in a factory every 8 weeks or so.

All Roads Lead to NFPA 1192!

All of the rules and regulations I’ve mentioned – and there are legion – there are four that stand out to me as an RV designer:

  • 49 CFR 571: Federal Motor Vehicle Safety Standards. These are the laws that govern highway safety like brakes, tires, GVWR, etc.
  • NFPA 1192: This is the heart of the “RV code.” NFPA 1192 governs the plumbing, propane, life safety, fire safety, and vehicular requirements of RV construction. It’s not a super long document, about 70 pages, but there’s a lifetime of knowledge within.
  • NFPA 70 (NEC) Article 551/552: This governs RV “high-voltage” electrical code. 
  • ANSI LV Standard: This governs RV “low-voltage” electrical code.

I used to spend a lot of time within NFPA 1192. You can find rules on waste tank design, vent pipes, trap arms, propane pressure drop tables, LP tank mounting, onboard generators, battery venting, transfer switches, branch circuit design, egress windows, shower pans, slide out room activation, flame spread, furnace exhaust location, smoke alarm location, safety chains, operational electrical tests, and much, much more! This is the document that really digs into what makes RVs different than a house or a car. 

All these standards govern RV systems, not the RV “house” itself. This is, perhaps, the biggest difference between RV building codes and residential home building codes. A home’s construction is carefully controlled by building codes, usually some adopted version of the IRC and its appendices. There is no such adopted standard for RV construction. There is no 3rd party building code for RV sidewalls, roofs, cabinetry, frames, flooring, etc: No live load requirements, no minimum wind load strength, no maximum frame deflection, etc. These decisions are all under the purview of the first- and final-stage manufacturers. When you buy a Lippert travel trailer frame, you’re trusting Lippert. When you buy an East-to-West travel trailer with stick n’ tin sidewalls, you’re trusting East-to-West. When you buy a Grand Design 5th wheel with an AlphaSystems TPO roof, you’re trusting those two manufacturers: one for the roof trusses, one for the membrane. 

Should RV Building Codes Be Expanded?

Unfortunately, these autonomous issues are often the problems that afflict RV owners. Yes, there is a code for how a shower pan must be designed. No, there isn’t a code for how the shower pan must be mechanically supported, or whether it must be easily removed from the bathroom without tearing out the toilet as well (ask me how I know). Yes, there are electrical codes for the air conditioner, but no Manual J calculations for cooling loads. Yes, there is a plumbing code; no, it doesn’t require shut-off valves.

Most of these omissions are made under the claim that an RV is a vehicle for recreational use, not a domicile, and therefore extra regulation would be an undue burden. Plus, RV manufacturers produce hundreds, even thousands of floor plans. If each of these floorplans had to be individually certified – well, you can imagine the added cost.

Some RV owners are calling for more stringent building codes. I get their frustration. I can’t imagine buying a $70,000 RV only to have it sit in the service center for the first two years because the water heater was installed incorrectly or the shower wouldn’t stay watertight. That’s maddening.

As of now, I don’t have a strong opinion either way. I tend to believe that codes are for safety; capitalism is for quality. Let the market decide; let the chaff separate. A lower barrier to entry allows more competition, which increases market choice and quality. Some of the best RVs you can buy are made by small- and medium-sized companies of 10-100 people. How would additional regulation affect them? I’m not sure, to be honest …

The equal marketplace ideal is the theory endorsed by Adam Smith, anyway, but the massive consolidation in the RV industry is unfortunately swallowing up much of the competition. We’re at risk of an oligopoly. I always tell people, “Vote with your dollars,” but I understand that voting is hard to do when the pool of candidates is guarded and shallow.

On the other hand, customers want better quality, but is more code really going to help? You can’t legislate sidewall delamination out of existence. You can’t write a code stipulation that outlaws loose ground wire connections because the installer didn’t use a torque screwdriver.

Yes, RV trim and molding often shake loose because manufacturers use too few too-small pin nails, but do we really want a bureaucratic agency governing the use of fasteners in cosmetic applications? Safety belts and headlights are one thing; staples and screws are another. And no amount of code can fix build quality, which I believe is a far, far bigger issue than design flaws.

I am certainly of the opinion that the RV industry needs far stricter code enforcement. Many of the problems I see (and even a few that I’ve caused, I must admit) are due to not following the manufacturer’s installation instructions, a problem already technically under the purview of code.

Takeaway: Vote With Your Dollars!

I’m about to work myself into an existential crisis, so I’ll stop here. To summarize: Yes, RVs are built to a code – quite a few, in fact! The heart of the design code is NFPA 1192, but it doesn’t regulate most of the construction of the RV house. It focuses on plumbing, electrical, vehicular, propane, and life safety systems.

But truthfully, code can only do so much. Build quality and customer service are what separate the wheat from the chaff, and you can’t legislate quality. Instead, vote with your dollars, and don’t settle for less, I don’t care how big of a deal the salesman gives you!

4 responses to “Are RVs Built to a Design Code?”

  1. Miles

    Kind of funny that the very minimal standards beyond life safety and roadworthiness can be described as being “built to a code.” That is the very thing the RVIA has put all its resources into fighting against, given the legendary lack of durable performance in the industry perennially tempting lawmakers to represent their constituents’ interests instead and do exactly that—establish a code and lemon-law accountability for not meeting it in practice. That is the manufacturers’ nightmare in a nutshell. Next thing they knew, they would have to get actual PE’s involved in the construction plan of new units.

    1. It is quite the conundrum, isn’t it, Miles? Similar to the U.S. automobile industry in the 1970s, I believe the RV industry could use a shakeup, but I don’t know if it should come from government regulation, grassroots revolution, or market pressure. Single-family homes are built to a relatively strict building code, but there are plenty of brand-new homes with leaky roofs and moldy attics after the first year. It would seem to me that truly enforcing the current code might be a good first step, since many of the problems I’ve seen are from a lack of QC, not necessarily a lack of code on paper.

  2. David Camilleri

    As a former RV design engineer can you give a recommendation of how to reinforce the frame on a fifth wheel trailer that is experiencing horizonal cracks in the frame web above the spring hangers? As a former stuctural Ironworker certified welder my approach would be to add full length vertical gussets on each side of each spring hanger on the outside of the frame. Inside too would be great, but not practical. Then install a steel member either angle iron or square tubing to be welded on the spring hanger on one side of the rv and span to the other side, covering the majority of the verticle portion of the spring hanger and welded to both sides of the end of the hanger so as not to impede the leaf spring assembly. Any thoughts? Another thought I had was to take a piece of steel channel iron and fit it to set inside the flanges of the frame vertically above the spring hanger and weld all around to remove flex from that area.

    1. David, I appreciate all the information. As you can imagine, for liability reasons, I can’t give specific answers to your questions. If you reference this article (, you’ll some pictures of what RV OEMs have done to reinforce the spring hanger mounting locations. But if the webbing in your main I-beam is already cracked, you will likely need additional reinforcement.

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