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Truck Camper Maintenance

Routine RV Water Heater Maintenance

Suburban or Atwood, here’s how to flush, winterize, and complete RV water heater maintenance.  Ever experienced that rotten egg smell?  Here’s how to solve that, too.

RV Water Heater Maintenance

Have you ever turned on the hot water faucet in your camper and smelled rotten eggs?  This stinky sulfurous experience has happened to us with many campers, especially if the camper hasn’t been used for a month or two.

When we picked up our new-to-us eleven year-old camper at Truck Camper Warehouse last summer, we were immediately greeted with that horrible rotten egg smell when we turned on the hot water.  We knew exactly what the problem was; our water heater needed to be flushed.  The rotten egg smell had to go!

Since we live in a HOA community that doesn’t permit RVs, much less allow work on our camper for an afternoon, we drove out to fellow truck camper friends John and Marylou Wells’ farm.  They invited us to their home to work on our rig, and de-stink our water heater.  Now that’s friendship!

Suburban and Atwood

The two major suppliers of water heaters in the RV industry are Suburban Manufacturing and Atwood Mobile Products.

No matter which brand of water heater your camper has, we recommend visually inspecting your water heater at least twice a year.  To keep things simple, we inspect our hot water heater when we winterize in late Fall and de-winterize in early spring.  It’s a good habit to visually inspect your entire rig at these times, especially your camper seals.

Of course, even babies know that you can’t play with your belly button if you don’t know where it is.  Since we’re fairly sure you all know where your belly buttons are, we’ll start with locating your water heater.


In the photos above are the two most common water heater access panels found on truck campers; the Suburban (above), and the Atwood (below).


If your camper is equipped with a water heater, you will find one of these two access panels on the driver’s or passenger’s side of your truck camper.

Once located, you need to open your water heater access panel to being the inspection and maintenance.  To do this, twist the metal or plastic latch at the top of the water heater access panel, and lower the panel door.


Tip: If your access panel has a plastic latch, or a rusting metal latch, you can upgrade or replace that latch with a new metal latch that will be more resistant to breaks.  A broken latch can result in a lost water heater access panel, an expensive item to replace.

Most RV water heaters run on propane gas.  Some water heaters also feature an electric element that heats the water if you’re plugged into shore power.  This is a fantastic option as it saves propane when you’re plugged in.

water heater conversion to electric kit

Tip: There are available kits for adding electric heating elements to propane-only water heaters.  If you upgrade, make sure that the kit you purchase is compatible with your specific water heater.


We have a Suburban Manufacturing gas-only water heater installed in our camper, model SW6D (shown above).  Like the rest of our truck camper, it’s eleven years old and shows signs of age.  In a future article we will be replacing this unit with a Suburban SW6DE.  The “E” at the end of the model name indicates that the new water heater features an electric element.


If you have an Atwood water heater, it will likely look like the image above.  This Atwood water heater was photographed on a Lance Camper, compliments of Mike Tassinari.

During your twice a year routine RV water heater maintenance, it’s important to look carefully for loose connections, corrosion, insect intrusion, and insect nest building.  Any of these issues can prevent a water heater from working properly and may require service.

If you find dirt, dead bugs, or a wasp’s nest, remove this debris carefully (especially if the wasps are still home).  If there are potential electrical or propane gas issues with the water heater, those repairs require certified RV repair service.  For future content, TCM intends to engage both Atwood and Suburban for detailed information on proper water heater trouble shooting.

Suburban Water Heaters and Anode Rods

An anode rod is a solid metal cylinder that gets screwed into a water heater’s drain plug to prevent the steel water heater tank from rusting inside.  Anode rods are made from aluminum, magnesium, or zinc, all metals that will “sacrifice” themselves through electrolysis and save the exposed steel water heater tank from a similar fate.

If you have a Suburban water heater, the tank is porcelain-lined steel and requires an anode rod to prevent corrosion of the steel tank.  If you have an Atwood water heater, your water heater tank is aluminum and does not require an anode rod.

Note: We have read about Atwood water heater owners who have installed anode rods in their drain plugs to prevent the steel threaded drain insert from corroding.  This has been reported to be a source of potential leaks as the steel drain insert can eventually rust.  TCM will seek to clarify this directly with Atwood for a future update.

If you have a Suburban water heater, it’s important to check the anode rod when you’re inspecting your water heater.  Failure to replace a spent anode rod will result in premature tank wear, possibly lead to a messy tank leak, and can void the warranty.
Above: A Suburban magnesium anode rod

When an anode rod has lost approximately 75% of it’s original mass, it is time to replace the anode rod.  Fortunately, anode rods are relatively inexpensive, usually last a couple years, and are easy to replace.


Above: When we checked, our anode rod had about 50% of it’s original mass.  To be on the safe side, we replaced it with a new anode rod.


Above: TCM reader, Rex Carroll, sent in a picture of an anode rod, which was down to the metal core (lower anode rod).  This rod was no longer protecting the water heater tank.

Flushing and the Rotten Egg Smell

At least once a year, as part of your routine RV water heater maintenance, it’s a good idea to flush your water heater with fresh water.  Flushing will help rid any calcified sediment and deposits that collect in water heaters over time.

A flushing wand is optional, but highly recommended as it helps to increase the pressure of the fresh water and direct it deeper into the part of the water heater tank that is below the drain.  This pressure will also do a better job of loosening any calcified build-up inside the tank.


Above: A flushing wand will loosen and flush debris in your water heater

To get rid of the egg smell, you need hydrogen peroxide.  Yes, the same stuff some folks gargle with, and others use to clean wounds, works wonders to eliminate the egg smell from water heaters.

Anaerobic bacteria reacts with aluminum or magnesium (RV industry standard) anodes to produce the rotten egg smell.  That’s why peroxide, which is a germicide, is commonly used for flushing water heaters.  We recommend having at least one 16 ounce bottle of hydrogen peroxide for this task, preferably two.

Tip: If you don’t want to use hydrogen peroxide (which is toxic if swallowed) you can also use household vinegar.

Tip: To further prevent the rotten egg smell, use an aluminum-zinc anode.  The zinc in a aluminum-zinc anode helps to eliminate the bacterial activity that produces the hydrogen sulfide, and the dreaded egg smell.

Here’s a step-by-step process to flush a RV water heater, and rid the rotten egg smell:

1. Before you start, check that the water inside the water heater to make sure that it is not hot to prevent burning yourself.  Then, turn off the water pump and/or city water, and make sure your water heater is off.

Note: Never turn on a propane water heater or water heater electric heating element when a water heater tank is empty.  Even a brief power-on to the electric or propane heater element while the tank is empty can damage or destroy the heater element and/or water heater tank.

2. Open the hot and cold water faucets in the camper to drain any remaining water out of the lines.  This is an important step to relieve any pressure in the plumbing system.

3. If your water heater system is equipped with a bypass, use it to close off the water to the water heater.  That way water from the fresh tank cannot possibly enter the water heater.


4. For our Suburban water heater, we used a 1-1/16” deep well socket on a 3/8” ratchet with a 3” socket extension to remove the drain plug and anode rod.

Other water heaters may need a different socket size to remove the drain plug (Atwood) or drain plug and anode rod (Suburban).  Please check the water heater owner’s manual to determine which socket size you need.


In the picture above you will notice that the drain plug and anode rod in our Suburban water heater appears quite rusted.  This is an indication that the anode rod needs to be replaced.


Above: Plastic water heater drain plug on an Atwood water heater


Above: Brass water heater drain valves can be used to easily drain the water from the heater (without getting out the wrench) between camping trips.  Doing so will help to prevent smelly water.

Rant: Water heater drain plugs are notoriously difficult to access and remove.  This can be particularly frustrating if you need to access a drain plug to drain a water heater for winterization.  There you are, freezing your butt off, trying to reach a plug that should be a straight shot.  We have used many choice words for the folks who decided to put these drains where they are obstructed from clear access.

water-heater-anode-rod-3-drain-tank water-heater-anode-rod-4-drain-tank water-heater-anode-rod-5-drain-tank

Above: Draining the water heater – click to enlarge

5. Once the drain plug (Atwood) or drain plug and anode rod (Suburban) is removed, allow the water to drain completely from the tank.  You can open the relief valve to allow air to speed up the draining.


Above: The relief valve on our Suburban water heater

Tip: TCM reader, Rex Carroll, sent in the following tip about this part of the process.

“Since the water may have rust in it, or water deposits that might stain your driveway, you may want to use a large bucket to catch the draining water, or at least be ready to hose down the driveway.  Also, a 1 and 1/16” socket is not commonly included in most home socket sets.  You can either buy a set of large sockets at Home Depot or Lowes, or go to your local auto parts store and purchase an individual socket.”

Having had our fair share of rotten egg water on our shoes, we agree with Rex about being careful with the water that comes out of a water heater, especially if the water has been sitting for any period of time.  Smelling like rotten egg water is an excellent way to loose friends.

6. Next, spray fresh water into your tank with your fresh water hose.  We did not have a flushing wand on hand, so we used the old “put the hose in the tank, plug the tank until it’s full of water, and then let the water rush out with the sediment and debris” process.  It worked great, but a flushing wand would be even better.

7. Once the flushing was complete, it was time to put the hydrogen peroxide (or vinegar) into the tank and eliminate the egg smell.  To put the hydrogen peroxide into the tank, we used a polyethylene tube with a J-shaped funnel.


We used Duxseal reusable sealing putty around the tube and relief valve to create a seal.


Above: We used the funnel and the tubing to add the hydrogen peroxide to the water heater.

8. Once the entire bottle of peroxide was in the water heater, we turned the water heater bypass back to normal and filled the water heater with water via the camper fresh tank.  We also turned off the faucets in the camper and turned the relief valve off.

Then we turned the bypass off again and let the water heater sit with the hydrogen peroxide.  Peroxide kills bacteria almost immediately, but we let it sit in the tank for a while for good measure.

water-heater-anode-rod-12-debris water-heater-anode-rod-14-debris water-heater-anode-rod-13-debris

Above: The debris that came out of our water heater – click to enlarge

9. A few hours later, we took the old plug off and allowed the water heater to drain the peroxide-water mix.  In the pictures you can see debris and blue lining of the Suburban that has been shed.  Unfortunately, lost lining indicates that we need to replace the eleven year-old water heater in our camper.


10. Once the water heater tank was drained, we flushed it again with the fresh water hose.  More debris and blue lining flakes flushed out.

If you are merely flushing your water heater tank (no hydrogen peroxide or vinegar), you can skip steps 7 through 9.


11. With the hydrogen peroxide drained, and the tank flushed until no more debris came out, it was time to insert a new anode rod in our Suburban.  Before inserting the anode rod into our Suburban, we wrapped the threads with white teflon tape to create a tight seal, and prevent possible leakage.


Above: White teflon tape to creates a tight seal and makes it easier to remove the anode rod later

Again, Atwood owners may not need an anode rod, unless they are experiencing odor problems.  If you have an Atwood water heater and opt to use an anode, we recommend an aluminum-zinc anode.


Above: The brass adapter on the anode as it was being inserted into the water heater

The aluminum-zinc anode rod came as a kit with a brass adapter for use with either Atwood (small thread) or Suburban (large thread) plugs.  The kit included a small drain valve, but we opted to plug this hole with a 1/4” NPT thread brass plug instead.  Removing the anode rod completely is much faster for draining, and allows for the recommended twice a year inspection.  The brass plug also won’t corrode, and will last longer.


Above: Tighten up the drain valve and you’re done

12. Before refilling the water heater with fresh water, we opened the pressure relief valve to allow air to bleed from the tank.  Then we turned on the bypass valve and turned on the camper water pump (you can also use city water, if available) and allowed the tank to fill until water came out of the pressure relief valve.

We closed the pressure relief valve and opened hot water taps in the camper sinks to remove the remaining air in the camper plumbing.  Once the tank is filled with water, propane or electric heat can be turned on to supply clean hot water.

When the water pump stops, slowly open up a hot water faucet and run the water.  If you get spurting water, then there is air in the plumbing system that needs to be purged.  That process should only take a minute or less until the air is purged and water is flowing through the camper plumbing system as normal.

Note: If you used hydrogen peroxide (which is toxic), you may want to fill and drain your water heater a few more times to completely rid the water heater of hydrogen peroxide.

The tank is now fully operational, egg smell free, and ready to go with a new anode rod.  To practice what we preach, we will be doing our routine RV Water Heater Maintenance at least twice a year to make sure that it is in good condition.

Other Resources:

Also Recommended:

Paul Harris, Lance Camper’s General Manager of Customer Service, worked with TCM on an article called, “Ask the Expert: Truck Camper Holding Tank Systems”.  Paul’s article gives some excellent tips on properly maintaining fresh, grey, and black holding tanks.


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