RV Water Heater Basics: Use and Maintenance

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RV water heaters supply hot water that you need for showering, cooking, doing dishes, and other works that require hot water. It’s a small unit that could be a lifesaver when you’re camping in winter. As an RV owner, you should know how to use hot water heater in camper and other basics to utilize the full functionality of this useful machine.

Remember that operating and maintaining hot water heaters for RV is quite simple. All you need to know is the right use of this unit. Proper maintenance will keep it functioning for many years.

What Does an RV Water Heater Run On?

The first thing about learning the basics of RV water heaters is to know about their power source. You are most likely to have a propane-run unit because electric RV water heaters are a feature of luxury trailers and Class A motorhomes.

A propane heater is likely to have a tank between six and 10 gallons. On the other hand, an electric heater needs just electricity to function. Some heaters may have a hybrid power consumption system that is compatible with both propane and electricity. You will need to check the manual for camper hot water heater instructions to find out the exact power source.

electric rv water heaters
An electric water heater.

How to Use RV Water Heaters

To learn about RV water heater operation, you should know about the basic preparation, tips to start the pilot switch, and the use of both propane and electric heaters.

A. How to Fill RV Hot Water Heater

If you are using the heater for the first time, it’s necessary to fill it up with enough water before switching it on. For most trailers, you can do it by following these steps:

  • Open the heater’s bypass valve, so the water can flow into the primary tank.
  • Connect the trailer to a water source and start the onboard water pump.
  • Now, water will start flowing from the external source to the heating tank as soon as you turn the hot water tap on.
    The tank should have a “fill” line and you should fill up the water to that level.
  • It’s better to empty the water heater tank when not in use for a long time. If you are going to take a break from camping during the off-season, it’s better to empty all water tanks. Otherwise, these waterlogged tanks will grow mold due to the long period of inactivity.

Before filling up the tank, you should check the user manual for the heater. A specific model may have some specific requirements that you need to follow for a smooth operation.

B. How to Start Hot Water Heater in RV

The heater in your RV can run on electricity, propane, or a combination of both. To learn how to turn on water heater in RV, you will need to figure out the heater’s type and its power source. Once it’s done, following these steps will help you switch it on correctly:

Starting an RV Electric Water Heater

An electric travel trailer hot water heater runs on electricity. This is the most convenient option if you are camping in a place that has an electric supply. You can also drydock with an electric heater given you have an inverter.

Turning on an electric heater is easy since there should be a dedicated switch for starting on/off the appliance.
These heaters are better choices if you want to save on the cost of propane. However, the heating element in them can easily get fried up if you are not careful.

How to Kick off an RV Propane Water Heater

A propane heater is the most convenient option for drydocking and in campsites that don’t provide electricity. Many RVers don’t like propane appliances because of the liquified gas’s flammable property. However, the risk will be minimal if you take regular care of the propane lines and maintain the heater.

Some propane heaters have a direct spark ignition. In that case, there will be a switch in the trailer for turning it on/off. But most of them come with a pilot light that you need to ignite to switch on the heater.

Follow these steps for how to light RV water heater pilot. Remember not to light up the pilot in a moving trailer. It has to be parked and leveled to start the heater safely.

Push Pilot Knob

There should be an access panel in the water heater. Open the panel cover after switching on the propane tank. Inside the access panel, you’ll see a control knob. Flick the knob to “pilot” and then press it down.

how to light rv water heater pilot
Pilot knob of a propane heater.
Light up the Pilot

When pressing down the pilot knob, light it. Ask an assistant to do this or use a long match or gaslighter. Continue keeping the pressure on for around one more minute. It should be enough to light up the flame.

Finish the Lighting Process

A lit-up pilot means it’s time to release the knob and flick it to the “on” position. Set the water heater temperature to your preferred level. Congratulations! You’ve successfully lit up the heater’s pilot.

If the pilot does not light up, you have to repeat these steps. In some cases, it may take a few tries for the heater to come to life.

If the heater does not start at all even after multiple tries, you are probably looking at a bad thermocouple. The good news is that a new one costs only around $10.

Starting a Hybrid RV Water Heater

A hybrid heater is ideal for those RVers who often travel between traditional campsites and remote places. You can use both propane gas and electricity as the power source, depending on the facilities available on the site. Hybrid heaters are great for heating water quickly as it’s possible to use both propane and electrical power at the same time.

Like electrical heaters, these hybrid models have direct switches for turning on and off. There should be a single switch inside the trailer for controlling the propane heat. For the electrical heater element, you will find a switch outside the trailer. However, the switch placements could be different depending on the models of the trailer and heater.

Should I Leave My RV Water Heater On All the Time?

All RV water heaters have a built-in safety mechanism that makes sure that prevents the buildup of excessive pressure and the water from getting too hot. So, you can leave the heater on all the time without causing any safety hazards.

But keeping the water heater running is not practical at all. If it’s a propane unit, the fuel tank will be empty pretty quickly, which means a mounting fuel expense. On the other hand, keeping an electrical heater on may fry its heating elements.

To ensure a safe operation, always check the device’s user manual. It will help you get the best output without causing any safety issues.

Is a Tankless RV Water Heater a Practical Choice?

Whether you choose a propane, electric, or hybrid model, all of them will take some time to heat up the water. The quickest is the hybrid heater and that will too take 20 minutes or so to heat up a full tank of water. The waiting period can be longer in cold weather.

An RV tankless heater is a good option if you want to cut down on the waiting time for warm water. This device will provide a stream of hot water whenever you turn the faucet or shower on. It does not have any tank to maintain and the lasting period is around 15 years, almost twice the lifespan of a tank system.

However, this model has some disadvantages too, mainly related to the flow of water. If the heater is small, the water flow will be weak. Also, the water from the source has to flow with a certain pressure for the heater to turn on.

tankless rv water heater
A tankless water heater. (Credit: Camperism)

Maintenance of RV Water Heaters

A little maintenance will increase the lifespan of the heater by a few years. Regular inspection and cleaning will do the most work. Whenever you take the trailer to a repair shop, ask the mechanic to check the heater too to make sure that it’s working fine.

Cleaning the water tank once or twice a year is fine. However, draining the heater and cleaning the lines at the time of winterizing the trailer will prevent unexpected molding and rusting. Follow the same procedures before storing the trailer for a long time.

If you don’t have enough technical knowledge or DIY skill to perform the maintenance at home, take professional service. Do this at least once a year or during the preparation of a new trip after a long time.

A tankless heater will require less upkeep since it does not have a water tank. However, you should consider the pros and cons of all types before making a decision.


Learning the basics of RV water heaters will help you keep the device functioning on and off the road. Using it the right way and taking good care will ensure its service for years to come.

About Chris Coleman

Chris Coleman is an interesting travel blogger and outdoor photographer with a great sense of humor. He owns an RV Accessories shop in New York City so he has the knowledge necessary to provide thorough reviews and give advice on how to choose the right products for RV travel. He puts all that RV knowledge and experience to good use in his sharing posts. Besides product buying guides/reviews, Chris also writes informative articles, how-to articles and RV camping guides in his own interesting viewpoint. Chris’s blog is one of the most reliable information sources for RV campers no matter if you're an expert or a determined beginner.

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