The Ultimate RV Propane Tank Guide – Read This Before Fixing or Buying

Without question, the RV propane tank is one of the most important nerve centers of any RV. From cooking your food to cooling it, and from cleaning to showering, propane serves many functions in an RV.

RV propane tanks are not complicated, but there are some important differences and options that are important to take note of.

Because RV propane tanks do so much to add to the comfort and enjoyment you experience in your RV, let’s get to know them a bit better.

Types of RV Propane Tanks

There are two types of propane tanks found on RVs: ASME tanks and DOT cylinders.

ASME tanks, used most often on motorhomes, are approved by the American Society of Mechanical Engineers. In this case, the RV propane tank mount is the frame of the motorhome itself, so ASME tanks are not removable.
ASME Tank example. Photo credit:

DOT cylinders are used on travel trailers, fifth wheels, truck campers, and some small motorhomes. These are approved by the Department of Transportation. DOT cylinders may be mounted in exterior compartments, or RV propane tank holders on the tongue or bumper of the trailer.

RV Propane Tank Sizes

RV propane tank sizes vary widely depending on the type of tank and RV that you have.

ASME tanks on motorhomes can vary significantly depending on the size of your RV. While a small Class C motorhome may have a single 20-pound ASME tank, it is not uncommon for large Class A motorhomes to have tanks that hold 80-100 pounds of propane.

DOT cylinders used on travel trailers and fifth wheel trailers are typically much smaller, compared to their ASME counterparts, but the total carrying capacity of these units can sometimes rival those of large motorhomes. A small travel trailer or truck camper will typically have a single 20-pound DOT cylinder. By comparison, a large fifth-wheel camper may carry a series of 40-pound DOT cylinders, giving the RV a propane capacity of over 100 pounds.

Depending on your RV type and tank type, you may be able to expand your RV propane tank setup. If you plan to expand your RV propane system, be sure to work with a professional, certified in propane and propane accessories, who can give recommendations on the tank size and setup that will work best for your RV.

DOT cylinder example -
DOT cylinder example. Photo credit:

RV Propane Tank Gauges

If you have a motorhome with an ASME tank, it probably has an RV propane tank gauge built into it. This gauge has a needle showing how much propane is in your tank. This type of RV propane tank gauge utilizes a float inside the tank to measure the propane level. No matter which kind of tank you have, you’ll  want to take advantage of an RV propane tank gauge. These gauges let you know how much propane is in your tank so that you don’t run out and put yourself in a difficult situation.

DOT cylinders utilize different types of RV propane tank gauges, or sometimes none at all. While some higher-end DOT propane cylinders may have a built-in RV propane tank gauge, most will require an aftermarket gauge of some kind to be added.

RV Propane Tank Covers

While ASME tanks are affixed to the frame of a motorhome and take up part of the exterior storage of the RV, DOT cylinders are often kept outside of the RV on the trailer tongue or bumper. Because of this, many RVs have RV propane tank covers to protect the cylinders from road grime and weather conditions.

An RV propane tank cover is typically made of heavy-duty plastic or polypropylene, and come in a wide variety of colors and sizes to accommodate different-sized DOT cylinders and setups with multiple tanks. Tank covers are easy to remove and replace if necessary.

RV Propane Tank Holders

As mentioned previously, ASME tanks are affixed directly to the frame of your motorhome, but many DOT cylinders are kept on the outside of the RV.
RV Propane Tank Holder example. Photo credit:

Propane cylinders kept on the outside of the RV require an RV propane tank mount or holder. These holders are designed to keep the propane tanks safe and secure, while still allowing easy access for refilling.

An RV propane tank holder is made of powder-coated steel or aluminum and is typically equipped to hold two cylinders of the same size. They have a base plate, which is usually welded or bolted to the frame of your RV, that holds the weight of the two cylinders. The tank holder will then have a heavy-duty rod coming up from the center of the base plate, and a bracket affixed to the top of the rod to hold the two tanks in place. Some racks may come equipped with hoses and a changeover switch, to change the cylinder from which your propane system is drawing; if not, a changeover switch can be added.

Filling an RV Propane Tank

Because ASME tanks are mounted directly to the frame of your motorhome, you will have to drive your RV to a propane dealer or station to get your tank filled. Some stations allow you to pump your own propane, while others require a certified employee to pump the propane for you. Be sure to check with the dealer you are working with to determine how they handle refills.

DOT tank holder with changeover valve -
DOT tank holder with changeover valve. Photo credit:

Because DOT cylinders are not permanently mounted to the RVs that utilize them, they can be removed and taken to your propane dealer for refilling.

If you find yourself at a campground, and you are running low on propane, be sure to check with the campground office. Many campgrounds offer propane refill services on-site, and those that don’t will at least be able to direct you to a nearby dealer.

One important thing to note about filling an RV propane tank is that propane tanks may only be filled to 80% of their total capacity. The reason for this is that propane expands when it is subjected to heat. If a propane tank is filled to 80% capacity when it is cold outside, that same amount of propane, in the same tank, may actually take up 85-90% of the capacity of the tank on a much warmer day.

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