How Much Propane Does an RV Water Heater Use?

Written by Jeff Campbell in RV Propane

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Most RVs use propane for running the refrigerator, hot water heater, furnace, and stove. So, it’s wise to plan your trips so that you never run out. You’ve probably wondered, how much propane does an RV water heater use?

Here’s what I’ve learned over the years:

For a family of 3, on average, you’ll use 1.5 to 2 gallons of propane each week for the water heater if each member is showering daily. 

Relatively speaking, this is economical and is about the best heat source because in about 30 minutes you can have hot water that’s enough for one person to shower.

The tank’s capacity, the frequency of water use, and the outside temperature are some of the factors that would affect how much propane is used.

Let’s dive right in…

How big of a propane tank does my RV have?

Class C RVs have propane tanks ranging between 20-40 gallons, Fifth Wheel RVs often have tank sizes between 40-60, while Class A RVs often have propane tanks of 80-100 gallons. Travel trailers and Class B RVs often have 20-gallon tanks.

But of course, every RV make and model is different, so double check your manual to be sure.

If you are considering long trips, those with a capacity of 33lbs are the way to go because they can go longer between refilling.

The kind of propane tank your rig has depends on the type of rig. Some have a capacity of 7 pounds, and some could hold 100 pounds of propane.

What you have and what’s ideal depends on the kind of RVer you are.

There are two types of cylinders: ASME and DOT cylinders. ASME is an acronym for the American Society of Mechanical Engineers. These cylinders are approved by the association. They are mounted on the RV, so they are not removable.

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

They’re often smaller than their ASME counterparts.

Interestingly, their capacity often rivals the latter. A small truck camper or travel trailer would have a DOT cylinder with a capacity of 20 pounds, while a large fifth wheel may have a couple of 40-pound DOT cylinders giving the rig a propane capacity of 100 pounds or more.

Are you going to be spending a lot of time at a campground where you can hook up to their amenities, or are you going to spend most of your time boondocking?

If you’re into the latter, you’ll need a propane tank that’s of considerable size. And that also means you’ll need a propane regulator to control the flow. Of course, as I hinted at above, the type of rig you have is the key factor.

I will say in my Newmar Bay Star, which is a 25 gallon tank, I’ve only refilled it once in the past year, and even then, it was only down to half a tank.

So while we don’t use it every week, it’s very economical.

Are RV propane tanks measured in pounds or gallons?

RV propane tanks are often expressed both in the gallon capacity as well as the weight of the tank itself. Generally speaking, the number of gallons will typically be 25% of the number of pounds.

For example, my tank holds 25 gallons of propane and is a 106-pound tank.

So don’t be surprised when you see one set of numbers or the other. Ultimately the gallons number is the one you want to pay attention to. The larger that number, the less often you’ll have to fill it up.

Should you leave the RV hot water heater on all the time?

There is no need to turn off your RV’s hot water heater directly. When the RV is not in use, simply cut the power to turn the batteries and inverter off (often just 1 switch on the main panel), and that will cut power to everything, including the hot water heater.

Then it will simply kick back on when you flip the switch back on again the next time you use it.

Would leaving it on affect the water heater in any way? Not at all. On average, most water heaters have a 10-year lifespan and are not affected by how often you turn them on or off. But make sure there’s always water in it before you turn it on.

If there’s no water, you’ll damage it!

Now, most water heaters have an anode rod designed to prevent them from eroding. It’s a good idea to replace them annually as this would help elongate the water heater’s lifespan.

It’s also advisable that you clean out the water at least two times each year. Debris forms in it. If you don’t clean it out, the debris could affect the heating element such that it burns out!

So, it’s okay to leave the water heater on. It’s more convenient. It’s just that the cost and the environmental impact would be a bit higher.

How long does it take a 6-gallon RV water heater to heat up?

A 6-gallon water heater would heat up in about 20 minutes if you are using propane, while a 10-gallon water heater would heat up in about 35 minutes. 

Let’s check out the factors that determine the heat-up time.

They include The size of the hot water tank, the type of heat, outside temperature, and the temperature of the incoming water.

Most RV water tanks have a capacity of between 6-10 gallons, which heats up in less than half an hour.

That’s quite some time. But, it’s not too long. Water tanks with a capacity of 10 gallons naturally require a lot more time to be heated up.

Smaller RVs will obviously have a smaller tank, whereas Class A RVs probably have a 10-gallon hot water heater tank.

The type of heat source is another thing to bear in mind. 

You’ve got 3 options: Propane, electric, and gas. Propane is the fastest, while electric and gas take more time. Propane will heat a 6-gallon tank in about 30 minutes, electricity in about an hour, and gas will take about an hour, too.

And many may be able to switch between propane and electric, which are the most common options.

How long can you dry camp in an RV?

In a recent article, I said 14 days is the average time most RVers dry camp before they have to dump their tanks, charge their batteries or change the oil or gas.

Just click the link to read it on my site.

How many gallons of water does it take to shower in an RV?

On average, a family of three would use 18 gallons of water each day showering in an RV. That breaks down to 6 gallons a day per person for a relatively short hot shower.

And just like at home, the longer the shower, the more water gets used.

However, unlike a home, with a hot water heater tank size of 6-10 gallons, you can’t take a 30-minute shower and expect it to remain hot (or even warm).

It’s also important to know this if you’re trying to conserve water or you’re at a campground where you can easily refill. When you’re conserving water, 6 gallons of water for each person is a good average, and this translates to about a shower that lasts 5 minutes.

Of course, many of us camp in full-hookup campgrounds.

In that case, we’re hooked up to a water supply and not using the RVs freshwater holding tank. We are, however, still tied to the size of our RV’s hot water heater tank, assuming we’re doing hot or warm showers.

Is it bad to leave the water pump on in your RV? 

This is the theme of a recent article of mine where I explained that it’s not bad to leave it on, but you could be adding pressure to the connected water supply’s pressure if you’re at a campground, and that could overload your system!

Just click the link to read the article on my site.

How long can you shower in an RV?

For hot showers in an RV, expect the hot water to last about 8 minutes. Warm showers can last up to 12 minutes. But when hooked up to a campground freshwater supply, a cold shower can be maintained indefinitely.

Three factors act as constraints to having your usual leisurely shower.

They are: how much water you’ve got in your freshwater tank, the amount of hot water in your hot water tank, and how you dispose of the used water.

Bear in mind that a rig gets water from one or two sources: water from the freshwater tank or the campground.

Let’s check out 3 scenarios:

  1. Boondocking
  2. Hooked up but no tankless water tank
  3. Full hookup in a campground.

Boondocking

Because your water supply is limited, you’ll want to focus on efficiency. The “Navy style” bath is the common method.

You turn the water on a bit to get your hair and body wet, then you turn it off. Shampoo first, lather up, and then wash your body.

Turn the water back on to rinse your body, and then turn it off. This shouldn’t take more than 3 minutes. You’ll need a showerhead that allows you to easily turn the water on/off.

It’s estimated that the “Navy style” bath can save you up to 90% of the water that would have been used in a leisurely shower. If it’s feasible, you may want to carry water in a Jerry Can (as an extra source).

Hooked up but no tankless water tank

If you’re using water from your water heater, cold water flows in while you’re using it, which might not be hot enough.

The colder the water, the quicker you’ll run out of water that’s hot enough.

The water heater is relatively small compared to what you’ve got at home. So, there’s a need to be efficient, too. You’ll probably be able to shower for about 10 minutes. The time can be longer if you use some showerheads that are designed to save water.

It’s not leisurely, but it’s a tad more relaxing than the “Navy style.”

Full hookup in a campground

You can hook up to the campground’s source without worrying about your freshwater tank. But, it’s cold water. So, if you don’t mind a cold shower, otherwise you’ll have to heat the water before you can use it.

Of course, you’ll be able to take a leisure shower because the water source is near, and you can easily refill your freshwater tank. You can shower for as long as you like.

Thinking of living in an RV full time?

I have lived in my rig for 4 weeks at a time, and my wife and I may decide to live in it full time in the future.

So, I have considered the pros and cons, and in a recent article, I offered an in-depth guide that explores 25 of the most vital pros and cons.

You could save money on ownership and ongoing maintenance, and of course, you have the freedom to move to better weather. Check out the article for the full lowdown.

Just click the link to read it on my site.

RV Water Heaters - Learn about your RV water heater

Conclusion

We checked out a couple of interesting issues around how much propane an RV water heater uses.

We looked at how big of a propane tank an RV has if you should leave the water heater on and how long it takes a 6-gallon water heater to heat up.

We also looked at how many gallons does it take to take a shower in an RV, and we concluded by looking at how long you can shower in an RV.

Jeff Campbell

Jeff Campbell travels on and off with his 3 daughters in a Newmar Baystar Class A Motorhome. He writes extensively on both RVs, campgrounds, parenting on the road tips, remote learning & schooling, and much more!

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