Make sure your RV’s water heater has been full before attempting to utilize the hot water or take a relaxing shower (and is on).

Fortunately, filling your water heater is a straightforward, mostly hands-off process.

So that you don’t damage your heater in the process, let’s learn how to fill an RV water heater two distinct methods and some crucial facts.

How to Refill a Hot Water Heater in an RV

An RV hot water heater may be filled in one of two ways: by pumping water into it from the fresh water tank, or by using the pressure of municipal water that is attached to your water hook up.

Your hot water tank must not be in by-pass mode for any method (a setting you would typically use when draining the water heater and winterizing the camper).

In other words, your RV’s water heater is a component of your plumbing much as in a house.

Water will flow through the pipes and into the hot water heater when you attach a hose to the municipal intake.

When you turn on the pump and fill your RV’s water tank with fresh water, the water will be forced into the hot water heater.

Simply turn on any hot water faucet you have in your RV and run it until water begins to flow out and there is no air in the pipes.

It’s that easy.

Additionally, the procedure is roughly the same for all water heater manufacturers, including Dometic (previously Atwood) RV water heaters, Suburban water heaters, etc.

And that applies to all models, whether they are fueled by electricity, propane gas, or both.

Important: Wait until the water heater tank is full before turning on an electric water heater.

It will burn out the heating element if switched on while the hot water tanks are empty.

For further information, see our tutorial on how to activate an electric water heater in an RV.

How Can I Tell If the Water Heater in My RV Is Full?

Making sure your fresh water pump is “on” or that you are connected to city water before turning on a sink or shower hot water faucet and letting it run until water runs out continuously will allow you to determine if the RV hot water heater is full.

Run the water until it pours out smoothly if it spatters and sputters.

Additionally, if your hot water heater has a bypass kit, make sure the valves are not blocked so that water in the plumbing system is effectively forced to flow around the water heater (See diagram below for more information about bypass systems).

When your RV is taken out of storage for the winter in the spring, it is very vital to examine this.


Why won’t the hot water tank in my RV fill up?

One or more bypass valves may be partially or totally blocked, which is the most frequent cause of an RV hot water tank not filling up correctly.

Make sure the appropriate bypass valves are open for your system type.

Other potential causes include the following:

1. The cold inflow port of the water heater tank is blocked. Check the line connecting the bypass kit to the tank’s cold water input. Additionally, make sure that debris on the anode rod or deposits in the tank haven’t blocked the cold water entry.

2. Bypass valves need to be repaired.

3. It leaks from the drain valve.

Further troubleshooting advice may be found in your owner’s handbook.

Does the hot water tank in an RV fill on its own?

As long as it isn’t being bypassed, your RV hot water heater tank will fill automatically when you connect to city water or turn on your water pump.

To aid the flow of water through the system, turn on a hot water faucet in a sink or shower.

Where Is the RV Water Heater Bypass Valve?

Near the rear of the water heater, often where cold water enters and hot water exits the tank, is where you’ll find the hot water heater bypass valve.

You will have one to three bypass valves, depending on the kind of bypass system you have.

How To Fill RV Hot Water Heater Videos Suggestions From Youtube

How to Start & Use an RV Water Heater –
RVers How To: Make sure water is going in the water heater on a Little Guy Max – The Roads We Roam
Four Wheel Camper – Filling Water Tanks & Hot Water Heater – MainLineOverland

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Written by Bob Matsuoka
Bob Matsuoka is a blogger and founder of RVing Beginner blog. He has been blogging for over five years, writing about his own family’s RV adventures, tips for people who are interested in buying an RV or taking their family on an adventure by RV.