One of the conveniences of an RV is the ability to have running water.

We’ve talked about how to keep your fresh water system clean in the past. Now we will talk about your RV’s water heater. Most RVs come equipped with one – unless you have a pop-up camper or a smaller RV – and they can be in different tank sizes. Standard is six gallons, though larger, more expensive RVs can be 10 or 12 gallons.

Modes of Operation

To ensure your RV’s water heater is functioning as it should and providing all campers with ready hot water, you need to know the three basic types of operation – one of which will apply to your RV:

(1) There are manual water heaters that you light yourself (more uncommon now).

(2) There is an electronic switch that lights the water heater by your turning a switch. These switches don’t only turn on the hot water, they have safety features such as not allowing gas to flow if there is a failure to ignite. Electric water heaters are a great way to conserve propane.

(3) There are tankless water heaters or on-demand water heaters that provide hot water immediately. Tankless water heaters are quickly becoming the norm, or you can upgrade to one for your RV. As long as you have access to water, you can have hot water on demand with this mode of operation. This is handy if you have high water consumption, such as several campers using the shower.

All water heaters operate on LP gas or a hybrid of LP gas and electric. For LP gas only, you’ll also need 12-volt power from your RV’s charged battery. Gas-only can be great for boondocking because you don’t need to rely on electricity to make the water heater operate. The hybrid types need both LP gas and 120-volt AC. Electric water heaters take more time to warm up and they use a decent amount of electricity; however, you can run both modes simultaneously and speed up the process.

Note: Never light a water heater unless you know there is water in the tank, otherwise you could cause damage. Also, don’t allow anyone near the exterior water heater vent as it can get extremely hot.  

Adding Water

How do you add water to the tank? It’s easy: Connect the RV water supply to a freshwater source using your freshwater hose connection. Make sure the water filter is present, too. Make sure the water heater switches are turned off if electric, and disconnect the propane tank if the water heater runs on gas.

Turn on the pump and open a hot water faucet and allow it to run into the stream of water is continuous. Once the water pump turns off and the tank is full, you can turn on the water heater. Keep the water heater panel free of bugs and debris, which can be wiped away with a cloth.


There are some preventive maintenance tips for your RV water heater that you can and should perform, because doing so will add years to the life of your RV water heater.

  1. Drain the water heater tank after each trip to help prevent stale water and unseemly odors. Simply turn off the water supply to the RV and allow it to cool completely, open the hot water faucet to relieve pressure, and remove the drain plug located on the water heater. Certain brands of water heater have an anode rod inside, which protects the steel lining. Remove this rod before draining the tank and check the rod’s condition. If it looks depleted, replace with a new rod.
  2. Always drain your RV water heater before putting it into storage. If you don’t, the water could freeze and cause damage.
  3. Mineral deposits can accumulate at the bottom of the tank over time, so it’s a good idea to flush the water tank periodically, at least twice a year. You can also purchase a flushing tool that connects to a water hose. Use it to flush extra sediment out of your tank. You’ll know you’ve done the job when the water is clear.
  4. Insects can end up building nests in water heaters during storage. Clean your heater tube prior to the start of every RV season. Obstructions can cause the water heater to burn poorly or not heat up quickly.

Our partner Go RVing has several articles about winterizing and maintaining your RV’s water tank. Check them out here.