How Much Propane Does an RV Water Heater Use? (Free Calculator)

Hot water is one of those luxuries you can take with you when RV camping.

However, if you rely on propane to power your water heater, you will need to plan accordingly.

But, how much propane does an RV water heater use? Whether you want to ensure you have enough propane for your trip or simply want to calculate your water heaters operating cost, we’ve got you covered.

So, let’s learn how to quickly estimate your water heater’s propane usage. Plus, you can use our free propane usage calculator to effectively plan for future trips!

Let’s jump right in!

How Much Propane Does an RV Water Heater Use?

The amount of propane your RV water heater uses will vary depending on the size of the hot water tank, the heater’s BTU rating, how often and long you shower, how hot your showers are, the amount of hot water used for cooking, the temperature your water heater is set at… you get the point.

As you can see, it’s a tough question to get an accurate answer for. But, with a little math, we can get a close estimate. Let’s use a specific example:

A camper or travel trailer with a 6-gallon Suburban RV water heater rated at 10,000 BTUs will burn through 20 pounds of propane in about 42 hours of continuous use.

While that may seem like a lot of propane used in a short amount of time, it’s important to understand that your RVs water heater doesn’t run continuously. It only uses propane when it needs to heat freshly added water in the tank, which only takes about 10-15 minutes. So, technically, under the right circumstances, you could run an RV hot water heater on a 20 lb. tank for over a month.

Important: Your water heater is likely just one of several propane-powered appliances in your RV. Check out our guide titled How Long Does Propane Last in an RV? to help you estimate the propane usage of all your appliances (RV refrigerator, stove/oven, furnace, air conditioner, grill, etc.).

Using the above example, we can get ballpark answers to several popular questions campers have regarding propane usage and their water heater.

How Long Will an RV Water Heater Run on Propane?

Using the 6-gallon Suburban water heater above and the assumption that your water heater runs an estimated hour per day, it would take 42 days to burn through your typical 20 lb. propane tank!

If your water heater has a different BTU rating or you have a different sized propane tank, no worry. We can easily estimate how long your RV water heater will run by using the following equation:

  1. Propane gallons X 91,502 = Tank BTUs
  2. Tank BTUs divided by total appliance BTU usage = hours before running out of propane

For example, a full 20 lb. tank has 4.6 gallons. So, we would multiply 4.6 by 91,502 to get 420,909. Next, divide that number by the total BTU usage of our water heater, for example, 8,000 BTUs.

The answer of 420,909 divided by 8,000 comes out to 52.6. This means that we can run an RV propane water heater for 52.6 continuous hours before running out of fuel.

How Much Propane Does an RV Water Heater Use per Day?

Using our 6-gallon Suburban water heater example above and the assumption that your water heater runs on average an hour per day, it would burn through 0.11 gallons of propane per day.

We essentially took the number of gallons in the tank (20 lbs. = 4.6-gallon propane tank) and divided that by the number of days it would take to burn through a full 20 lb. propane tank to get our daily usage.

4.6 (gallons in propane tank) divided by 42 (days) = 0.11 gallons

How Long Will a 30 LB Propane Tank Last for Water Heating?

Again, using our original 6-gallon Suburban water heater example and the assumption that your water heater runs on average one hour per day, it would take 64 days to go through your typical 30 lb. propane tank!

Important: All of these calculations are just estimations. The only real way to tell exactly how long your propane tank will last is to test it out in the wild. This can be done easily and safely if you have two propane tanks. This way, you can see how long it took to get through one tank while still having a backup tank when the first one runs out.

RV Propane Usage Calculator

Quickly calculate your RV water heater’s propane usage with our calculator and chart below.

RV Propane Tank Sizes Chart

RV Propane Tank SizeGallons (When Full)
11 lb. tank2.6 gallons
20 lb. tank4.6 gallons
30 lb. tank7 gallons
40 lb. tank9.4 gallons
100 lb. tank25 gallons

You can use this calculator to estimate the propane gas usage of your other appliances, as well. For more information on the propane usage of other RV appliances, check out these resources:

Does an RV Water Heater Use a Lot of Propane?

RV water heaters use relatively little propane to keep the water hot in your camper. They don’t continuously run, so they only actually use propane when they need to kick on and heat the water (which will depend on how much hot water you use).

If propane use is a major concern, you can switch your water heater to electric mode (if applicable) and use your campground’s electricity to heat your water, as well.

But, all in all, RV water heaters use very little propane, which is why many campers leave their hot water heater on all the time.

Related: Should I Leave My RV Water Heater on All the Time?

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