How to Turn On the Electric Water Heater in an RV

Having trouble either locating the water heater switch or getting the water heater to work altogether? Let's go over the things you need to know about your water heater.

If you’re the brand new owner of your first RV, you’re probably too excited to sit down and go over the subtle nuances of electric water heater operation. When it comes time, you’ll be right here, and luckily enough for you, so shall we. When it’s time to power everything up, how to turn on the electric water heater in an RV?

Half of the battle is finding the electric hot water switch. Depending on which model you have, it could literally be anywhere, from directly on the water heater, to an electric panel, to the outside of the RV. The key is to find it and simply switch it on.

That’s really all there is to it. So long as your RV has a source of power, the electric water heater is ready to turn on and if there’s any confusion, it will revolve around locating it. It’s often not clearly stated where the water heater is in the user specs and even the manufacturer is liable to provide you with an inaccurate explanation.

Note: If you’re not sure how the water system in an RV works, click here.

Hunting down your RV electric water heater switch

That’s the real question, isn’t it? Outside of troubleshooting an electric water heater that isn’t working, finding the switch is often the hardest part. Here are some of the places where your water heater switch might be located:

  • Close to the sink 
  • Outside, in the panel
  • Directly on the water heater itself
  • Interior panel

If you’re having trouble locating the switch and it’s not amongst the other switches on your panel, try checking underneath the sink or somewhere around it. The electric water heater is usually installed close to where your primary water usage will be, that way there is not an extensive pipe infrastructure that is wasteful and unnecessary. 

When you open the sink cabinet, shine a flashlight around and see if the switch is located close to the exterior wall or on a small panel bolted into the sink cabinetry. You’d be surprised at how often this is the case, almost as if the manufacturer considered it an Easter egg hunt. 

In some models, the switch is located on the underside of the water heater itself. You’ll find it behind a removable panel on the base of the water heater, or at the base of the section of the water heater that is accessible. 

On some models, it’s on the bottom left of the water heater. Remove the panel and shine a flashlight in there (if necessary) and look to see if it is directly on the water heater itself or bolted to the paneling. 

The remainder of the location possibilities are going to be on the electric panel (circuit breaker), which is most often located outside. Occasionally, you’ll find the oddball RV with a panel on the inside but either way, if it’s not under the sink and not on the water heater itself, then it has to be in the panel by process of elimination. 

How to prep your electric water heater before turning it on

With a brand new RV, it’s not as if they loaded your water heater up with water for you, so that’s a task that’s left for you to take care of. Filling up the water heater isn’t too difficult of a job, however, it’s just a matter of making sure that it’s done.

If you flip the switch on without any water in your hot water heater, those heating elements are going to get pretty hot with nothing there to heat up. The unfortunate side effect will probably amount to a broken water heater that needs to be replaced. 

Though it’s rare, a fire hazard is also something to consider. Either way you slice it, it’s going to be an expensive repair.

Here’s how to prep your water heater before turning it on:

  • Locate the water intake valve for the electric water heater
  • Check over the manual to get an idea of the volume
  • Screw a standard water hose into the intake valve
  • There should be a water level indicator to watch
  • Close the water heater bypass valve so that water flows to the water heater
  • Turn on the spigot
  • Once you reach the fill line on the indicator, cut the water off
  • Open the water bypass valve
  • Turn on the water at the sink to ensure it is flowing correctly

Once you turn on the water heater for the first time, it will take approximately one hour or an hour and a half to heat the water supply sufficiently.

Can you leave the electric water heater switch on?

When your RV is not hooked up to a power source, then it doesn’t matter if you leave the water heater switch on or off, as there is no power flowing to it when you are on the road. It’s certainly not going to hurt anything. 

You should get in the habit of turning it off when you’re on the move, however, because there are extenuating circumstances where it might be important. If you’re using solar power generators, for instance, you never want to leave the switch on for long periods when it is connected to an inverter. 

When you are using an inverter, you should only have the switch on to warm up the water for everyone to use when it is necessary, such as washing dishes or taking a hot shower. When everyone is done, turn it back off, regardless of whether or not you’re hauling up stakes anytime soon. 

If you get in the habit of turning it off when not in use, you’ll save yourself some power if you’re using solar or any other kind of generator to power your appliances. 

Maintaining your electric water heater

If you’re breaking in a new RV, then you should set aside a routine schedule right off the bat. This schedule should include electric water heater maintenance, including the switch. Twice a year or annually, you should completely drain the water heater and refill it with fresh water.

Here’s how to drain and refill the water heater:

  • Flip the switch to off
  • Give the water heater time to cool down
  • Remove the drain plug and let it empty out
  • Pull the anode from the bottom of the panel
  • If the anode has lost 75% of its mass, replace it with a new one
  • Replace the drain plug and refill

Not every camper comes with an anode in the electric water heater but many models do. The anode is a sacrificial metal that is designed to remove corrosive elements from the water and sacrifice itself instead. Over time, it will lose its mass as the corrosion it takes on slowly increases. 

It’s necessary to replace the anode once a year so that your water will always be free of corrosive elements since the anode will keep the inside of your tank from corroding and passing it on into the water. 

If you notice that your switch is starting to get really stiff and hard to flip on and off, it’s probably time to replace it. Most manufacturers mount the electric water heater switch with a clip that is easy to remove. Ensure that no power is flowing to the switch and remove it. 

Once the wires behind the switch are exposed, you can check the operability of both the switch and the wires by testing the switch physically and using a multimeter to check for continuity. If you’re not getting anything, the switch needs to be replaced. 

If it’s just the switch and the stiffness remains (you’ll be able to see if it can properly open and close the circuit by flipping it on and off once you’ve removed it), you should simply replace the entire switch. It’s a better option than trying to find just the switch plate, with no components behind it. 

An alternative: Tankless electric water heaters

While most RV’s are going to come with a tank water heater, you have the option of replacing it altogether with something that is far more practical such as a tankless water heater. The tankless water heater will function almost entirely the same, however, there’s no tank.

That eliminates a great deal of maintenance both preventative and standard, annual maintenance procedures. When the RV is parked and the power is hooked up, you can flip on the tankless water heater when you are ready, heat only the water that you use, and flip it back off when everyone is done. 

It’s one of the most simple and efficient water heating systems ever designed and they’re relatively inexpensive, especially in terms of longevity and energy savings. They take up a lot less space as well. You can mount them indoors, in a safe and easily accessible area.

In fact, like solar generators, tankless electric water heaters (especially in an RV) have so much going for them it’s hard to come up with a reason not to purchase one and replace your standard electric water heater altogether. 

Final thoughts

The hardest part about turning on an electric water heater in your RV is simply locating the thing for the first time. After that, it’s just a matter of flipping the switch. However, always make sure that you have water in your water heater before you flip the switch.

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Thomas Godwin

Thomas Godwin is a writer and Marine Corps veteran with a degree in Creative Writing from the Full Sail University. He has been writing content for HeadlessNomad since 2021. Being a veteran, Thomas knows pretty much everything there is to know about the use of paracord, how boots should fit, and nature in general.