How to Maintain an RV’s Hot Water Tank

Just like a stick built house, the hot water system in an RV needs maintenance. Many tanks and heaters fail long before their time, because the owners didn’t bother or know how. Perhaps they didn’t read the owner’s manual.

Over time, minerals, sand, dirt and other contaminants can build up inside a hot water tank, impairing the heater’s ability to heat enough water for use and causing you to use more electricity/propane than you should. The anodized rods will also wear out sooner.

For those purchasing a used RV, performing maintenance from the start will help the existing heater and tank last. If you need a repair shop, at least you won’t have to replace the tank, or perhaps due to your efforts, not need a replacement.

The hot water heater is generally located on the side of the RV. If you don’t know where it is, open the outside hatch doors until you find it. Read your owner’s manual- it will show you. Perhaps someone at the RV park who has experience will help you.

Write down the make and model of the water heater you have in case you need to run for parts.

Step One:

Twice a year, flush the minerals and “gunk” from the hot water tank. This is far easier in an RV than a house’s hot water tank. Turn the water heater off at both the electric and propane fittings.

Go inside the RV and turn on a hot water faucet. The hot water tank will drain, and fill with cold water. You’ll be able to work safely with cold water instead of hot. When the water at the faucet is cold, turn it off.

Step Two:

Turn the city or RV park water connection at the spigot. This keeps water from pouring out while you’re trying to work.

If your water pump is on, turn it off.

Step Three:

Use a crescent wrench to loosen the nylon drain plug. When you can move it with your hands, loosen it all the way. When it comes loose, it will squirt water out from the pressure.

If your water heater has an anodized rod in the drain, you should replace it. These rods are designed to help retard the mineral buildup inside the tank. If the rod has been eaten away, you may be facing water tank replacement.

Step Four:

Turn the city water back on, and allow the tank to flush out for approximately five minutes. That white, flaky stuff you see is the mineral build up.

You can also use a water heater flush wand available from RV supply stores. Attach this wand to the end of a hose (not your freshwater drinking hose), and insert the wand into the tank, moving it around. The water should be on high to create a pressure wash inside the tank. This will remove a lot of material.

Step Five:

When the water runs clear, replace the rod/plug in the tank. Rinse off any residue from the outside.

Go inside the RV. Turn the hot water faucet on again and let the system get rid of the air in the lines. This will also allow the tank to refill.

Go back outside and turn the hot water heater on again.

That’s it you’re done flushing the hot water tank.

You’ll notice you have more hot water in less time, and your electric/propane bill will drop. Your happiness level however, will rise.

Source: Jim Twamley, “How to Flush the RV Hot Water Tank,” Wonder How To website, no date given