Tank Capacity: How Much Water Does an RV Hot Water Tank Hold?

Because of the lack of space in an RV or trailer, you will find that the water capacity of your water heater may not rival your traditional home water heater’s capacity. Learning to conserve is vital when you live in an RV or trailer.

The standard or common sizes of RV water heaters are either a 6 or 10-gallon size. It will depend on the size of your RV or trailer and which one you will get when you make your purchase. There are exceptions to this rule as the water heater makers make a variety of sizes for RVs.

To learn more about this issue, just continue to read our article. It has that information and also tells you that there are other sizes you can buy if you have the space for a bigger heater. It is all going to be about weight and space.

What Size Are RV Water Heaters?


The size of the water heater you will get will depend on the size of your RV or trailer. Smaller RVs, etc., as you know, will not have enough space to hold a large water heater.

Larger RVs, etc., will not have that problem as they will have the space for bigger water heaters. Right now you should be able to find this appliance in sizes from 4 to 16 gallons.

Most RV makers place either a 6 or 10-gallon water heater in most of their units. If you are not sure how large your water tank is or how much water it can hold, ask your dealer before buying or check the owner’s manual for the water heater installed in your unit.

How Much Water Does an RV Hot Water Tank Hold?

This will depend on the size of the water heater. If it is labeled as a 4-gallon model, then you can expect to be able to put only 4 gallons of water inside. As you go larger, then what is on the label will be the amount of water the tank can hold.

The larger the water heater capacity, the better it is for you when you need to use hot water for showers or doing the dishes. When you have a lower-capacity water heater, you do need to do some water use planning.

It may take up to 20 or 30 minutes for the water heater to heat the water in the tank. Time is a factor here when you use a lot of hot water. This is a reason why many RV owners go for a tankless model.

They get unlimited amounts of hot water all day long. That makes life a little easier when you have the kids along for the vacation.

Dometic RV Water Heater Capacity


We checked Dometic’s website and the company does not list a large number of water heaters for sale. On their web page, they show 10 results and the models they list are either 6 or 9-gallon models. We did see a separate web page for a 10-gallon model, but that seems to be the largest they sell online.

What they sell to the RV makers may be 6, 10, or larger water heaters. One RV parts outlet only seems to list 6 and 10-gallon models. That parts outlet also places both Dometic and Atwood in the same category and they may be the exact same water heater although they have different model numbers.

Dometic may have larger models but many of the models we came across on their website are not sold directly to the public. You would have to go to your nearest dealer to see what they offer.

Atwood Water Heater Capacity

As you know, Atwood is owned by Dometic so you may not see much difference in the size of their water heaters. There is a fact sheet put out for this brand and for standard gas and electric water heaters, Atwood sticks with the common 6 and 10-gallon sizes.

That is for RVs and trailers. If you own a boat, Atwood makes water heaters between 4 and 20-gallon sizes Then their international marine water heaters are sized between 6 and 20-gallon.

However, there are not a lot of choices between those numbers. For example, the last category only has 6, 11, and 20-gallon sizes. For RVs, you only have 6 and 10-gallon models to choose from.

The most variety you can get with Atwood would be its standard marine product line. There the water heaters go from 4 to 6 to 10 to 11 and finally to 20-gallon capacities.

Suburban RV Water Heater Capacity


Out of all the brands that make appliances for RVs and trailers, Suburban seems to be the company that has the most options available. The company’s website lays out all the capacity sizes you can buy.

The Suburban model line starts at a 4-gallon capacity, then their water heaters go up by little increments. After the 4-gallon size, you can find it in your RV or buy a 6, 10, 12, & 16-gallon capacity water heater. You can see this information at this link.

Suburban tries to make sure it has a variety of water heaters to meet your hot water needs no matter how big or small your RV or trailer is. Their models are the porcelain, steel tank models.

Like Dometic and other RV component making companies, you would have to find a dealer that sells these different models. It seems that Suburban does not sell directly to the public.

The cost of these and other brands of water heaters will not be cheap. We did not see any listed for less than $800

Biggest Capacity RV Water Heater

The largest water heaters we have found come from Suburban. They seem to be the only company making water heaters for longer showers. The largest they sell are 12 and 16-gallon capacities.

That is just for RVs and trailers. As we noted earlier, Atwood makes marine water heaters with 20-gallon capacities. If this type would fit in an RV, you may be able to upgrade and get a lot of hot water for your purchase price.

The trend seems to be going to tankless water heaters. Part of the reason is that they take up less space in your RV, etc. Less space needed for a water heater means more space for another component.

Another reason RV makers and owners are going to a tankless version is that they supply unlimited amounts of hot water. That supply helps smooth out any rough spots in RV camping.

How Many GPM is a Camper Hot Water Heater?

This will depend on the type of water heater you buy. We have seen some models with a GPM as low as 1.32 and as high as just over 6 GPM. In looking at the different companys' websites this information is not usually listed in the specs.

The more important information that is discussed in the specs is the BTUs range as well as the recovery rate. Suburban has electric models that recover at the speed of 6 gallons per hour and gas ones at 10 gallons per hour.

Also, this topic seems to be reserved for the many tankless models on the market right now. The tankless models average roughly between 2 and 2 1/2 GPM. This is a topic you should ask your dealer when you are considering buying an RV or trailer.

What is a Good GPM For an RV Water Heater?

Most websites seem to be pushing the tankless model. They have the GPM for the models they review, however, they do not list the GPM for those models that come with tanks.

Part of the reason for this disparity in stats is the fact that tankless water heaters need a certain amount of water flow to work correctly. The tank models do not have this problem as the water is heated inside the tank.

The best that can be said here is that if you are getting above 1.3 gallons per minute, then you are doing fairly well. It would be ideal to have more water flow but not all tank water heaters put out a lot of water flow.

The real issue for tank water heaters is not going to be the GPM. It will be if the water heater’s tank is big enough to keep you in hot water until you finish your shower.

Some Additional Words

The standard RV and trailer water heater tank size will be either 6 or 10 gallons. The size of the RV you buy will depend on the size of your RV and who makes that RV or trailer.

You can find larger water heaters in larger RVs and trailers but you will still have to manage your hot water use to maximize the appliance’s potential. You won’t be in the shower for long periods of time unless you switch to the tankless models that are trending right now.

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