An RV Propane Tank Warning

Getting Your Propane Tanks Recertified

Scout Olympic Propane Compartment

Most slide-in truck campers are equipped with a propane system. This system, which provides fuel for absorption refrigerators, stoves, water heaters, and furnaces. consists one or two propane cylinders or tanks, a two-stage propane regulator, and a propane low-pressure manifold. The propane cylinders used in today’s truck campers and RVs come in a variety of sizes, the most common of which are rated for 20, 30, and 40 pounds, though some pop-ups and smaller hard-side campers, like the new Scout Olympic, use the smaller 5-pound propane container (shown above).

All propane containers used in today’s RVs must be outfitted with an Overfilling Prevention Device (OPD). This safety device became a requirement in 2002 and prevents propane containers from being overfilled, which for all containers is 80 percent of total capacity (the additional 20 percent allows for expansion during warm weather). OPD valves can quickly be identified by the triangular-shaped knobs with the letters “OPD” stamped on them.

RV Propane Tank Warning

Did you know that the Department of Transportation (DOT) requires that propane cylinders used in RVs be recertified for use every 12 years? The DOT does, though very few RV owners do it or even know that this requirement exists. What do technicians look for during the recertification process? That the valve guards are in place and in proper working order and that the container hasn’t been subjected to physical damage, such as scraping, denting, and gouging. Dents in containers are allowed, but must be limited in size and must not exceed the sizes specified in the propane recertification charts. The tank’s fittings are also checked to make sure they are in proper working order and do not leak. Failure to recertify can result in a nasty surprise on your next outing as many propane stations will not refill “expired” tanks.

How much does it cost to recertify a 20 pound propane tank? The costs vary but typically you can expect to pay anywhere between $5 and $10.

This 20-pound propane cylinder is due for its 12-year recertification in Nov 2021.

After the initial recertification, DOT cylinders must be recertified every five years thereafter. The date of manufacture can usually be found stamped on the outside of the valve guard or found stamped on a metal plate attached to the cylinder. If you regularly swap-out your tanks at gas stations and other propane service centers, your tank is probably okay, though you should check it to make sure it’s still certified and safe to use. Valves and propane fittings do leak and sometimes fail to close even when closed all the way. We had this happen to us in our last camper and encountered another truck camper owner who had this happen to him at the last Truck Camper Adventure rally. This is one reason why we periodically pressure test our camper and check for leaks using a manometer. This is also why we check our camper’s propane leak detector monthly to make sure it’s in proper working order.

Two more things. First, make sure your propane cylinders are properly fastened in your camper’s propane compartment. According to regulation, the propane containers should be mounted in such a way that they will not become dislodged when a load equal to eight times the container’s filled weight is applied to the container’s center of gravity in any direction. Second, when transporting a cylinder to be refilled make sure that the OPD valve is closed, that the plug or dust cap is securely in place over the valve, and that the container is secured during transit to prevent the container from falling or rolling. When transporting, each container should be transported in the same horizontal or vertical position in which they are designed to be used. We like to use a Tanksetter when transporting our single propane cylinder to the local filling station.

Final Thoughts

Have you ever wondered what the 20, 30, and 40 pound cylinder ratings actually mean? It isn’t how much the tank weighs when filled, it’s actually how much propane weight the cylinder will hold when filled. So how much will a 20-pound propane cylinder actually weigh when filled? Easy. Simply add the tare weight (16.6 pounds) of the cylinder to the propane capacity (20 pounds), which for the cylinder pictured above yields a figure of 36.6 pounds. Here’s more. To determine how many gallons this cylinder will hold when filled to 80 percent capacity, simply multiply the water capacity (WC) figure by .10 (47.6 x .10 = 4.8 gallons). To determine how much this propane will weigh in the cylinder simply multiply the WC figure, 47.6 by .42 (20 pounds).

About Mello Mike 769 Articles
Mello Mike is an Arizona native, author, and the founder of Truck Camper Adventure. He's been RV'ing since 2002, is a certified RVIA Level 1 RV Technician, and has restored several Airstream travel trailers. A communications expert and licensed ham radio operator, he retired from the U.S. Navy in 2004 as a CWO3 after 24 years, holds a BS degree, and now runs Truck Camper Adventure full-time. He also does some RV consulting, repairs, and inspections on the side. He currently rolls in a 4WD Ram 3500 outfitted with a SherpTek truck bed with a Bundutec Roadrunner mounted on top. - KK7TCA


  1. Several issues regarding propane
    1) There are two ways to recertify a tank. ‘Visual’ is typically done by a trained individual working for a propane supplier. My last one cost $15 for a horizontal 30lb tank ($230 replacement). They apply a label with their inspector code and an inspection date that is good for 5 years. ‘Hydrostatic’ involves removing the valve, pressurizing it with water above its service pressure and measuring the expansion. They re-stamp a test date on the tank and it is good for 10 years. A test will usually take a week, and costs $30+. Until visual inspections were permitted, recertification was typically a death sentence for ‘BBQ tanks’ due to cost. Visual inspections are only available for DOT-regulated propane tanks.
    2) A good way to ‘recertify’ is to swap your (20lb) out-of-date tank at your local propane exchange. They don’t object to turning in an expired tank and you can (potentially) get one with lots of years left. This is only useful if you need a 20lb vertical tank. Normally, propane exchange is not economical because you only get 15# of propane in a 20# tank but if a one-time exchange costs you a few bucks, it is a good deal to get a new(er) tank.
    3) 1 lb of propane contains 21.6kBTU of energy. If you want to know how long a tank will last, determine the consumption rate of your device and do the math. For instance, a 40kBTU furnace will consume just under, (40kBTU per hour / 21.6kBTU per lb =) 1.85 lb per hour, if it were to run continuously but it doesn’t. Assuming a 30% duty cycle (runs 18 minutes in each hour) then it will consume; 40kBTU per hour / 21.6kBTU per pound x 30% = .55 pounds per hour.

  2. Sometimes you can buy new ones so cheap that it isn’t worth getting a certificate. Besides the valves can start leaking even after certifying and they cost as much as a tank. This is of course for the size that most truck campers use. If I am going out for a long enough stay I make sure I have up to date tanks, at least one. Otherwise I fill at home with my own fill tank. I have forklift, man lift, and horizontal tanks that I fill at home, one tank is a liquid withdraw as well.

  3. We have stopped exchanging cylinders unless out of date or condition is poor. Filling our cylinders, we get closer to 20#, or pay for less if not completely empty. The tank exchange bins (often Blue) in our area only have 15# in them for about the same ~$20.

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