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Ask Dave: Should there be an anode rod in our RV’s water heater?

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses an anode rod in the water heater.

Dear Dave,
We have a 2018 Vanleigh Vilano 325RL with an Atwood heater. It had no anode rod. Last April we had our holding tanks and the water heater professionally cleaned at the Vanleigh Rally. The technician said it would be beneficial to have an anode rod in our tank and he installed one. What say you, yes or no? —Bob

Dear Bob,
Got your question on our recently created forum and even though I commented in the forum, I thought it was a good topic to dig into deeper!

Residential water heaters are typically made with an inner tank of steel coated with a ceramic or glass-like material to keep it from rusting. An anode rod made of magnesium or aluminum is used to act as a sacrificial metal or surface for corrosive ions in the water to attack and corrode it rather than the tank.

Atwood water heater w/o anode rod
Suburban water heater with anode rod

The two main types of RV water heaters have tanks that are either made of aluminum, like your Atwood, or are steel-coated with a ceramic or glass-like material such as the Suburban.

Atwood claims the aluminum tank resists the corrosion commonly found in the other type of tank and does not require an anode rod. Suburban has a magnesium anode rod installed to reduce damage to the tank. Both are designed to prevent rusting and corrosion.

Keep in mind the water coming from the campground source will typically be harder well water and not municipally treated like you would find in your home. That means it will have higher concentrations of minerals such as magnesium and calcium.

Both Suburban and Atwood can be affected by these minerals as they settle in the bottom of the tank and can not only clog your water heater but can limit the heating capabilities as well. Simply draining the water heater periodically will not get all the sediment out as the drain hole is usually slightly above the true bottom. Having it flushed professionally is one way to keep your tank clean.

 

You can flush it yourself with a water heater flush tube and a garden hose. Connect the flush tube to a garden hose and insert it in the drain hole after you have drained the tank.

You can find one on Amazon here.

You can also run white vinegar into the system through a winterizing hose and flush again.

Read more from Dave here

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CharlieB
11 days ago

Another option to consider. When I winterize I blow out my coach with 40-50 psi clean compressed air. At the water heater I remove the plug (plastic) and then apply compressed air at the city water inlet. This agitates and scours out any mineral accumulation in the tank. Then put the plug back in and bypass the water heater. Being a better safe than sorry owner I then pump RV antifreeze (-50 degree) through the water pump and thru out the coach plumbing running a small amount to insure any P traps are safe. Been doing it this way for 40+ years with no problems.

TerryH
14 days ago

I always thought the ATWOOD aluminum tanks use a 1/2″ MPT NYLON DRAIN PLUG, or a small drain valve in its place? If correct, and no 3/4 x1/2″ bushing, it would be impossible to install a 3/4″ MPT standard anode?

Montgomery D. Bonner
15 days ago

In RV School (Master RV Tech-Retired) we discussed this, it does not hurt to have anode rod in Atwood tank, but required in the Suburban models. Then 2010, suburban models were superior, since don’t have water heater in ours, cannot tell you if that still holds true. If manufacturing in Far East, believe quality has gone down across board.

Dick and Sandy near Buffalo, NY
15 days ago

Our first 2 Class A’s had Suburban water heaters with Anode rods which we replaced as necessary & flushed out once a year using the device shown in the article. Our present Class A has an Atwood water heater (just our preference) and we flush it out once a year also. Both styles have served us well for years on end. The key is to inspect all working appliances on a regular basis. If you have an issue with almost anything RV related go to YOUTUBE, look it up and you will see that someone has had the same problem and that there is a video on how to solve your issue. Don’t be shy. Take a chance fixing your own problems as best you can. You will probably surprise yourself and maybe go on to fix other problems. I feel bad for those that have RV’s that have no electrical, plumbing or other knowledge and have to bring their RV to a dealer/service center and pay for things they might be able to do themselves. Stay safe, Stay well and HAPPY THANKSGIVING

Billh42
15 days ago

Atwood states that the aluminum tank does not need a sacrificial anode to prevent corrosion. That’s been good enough for me for the last ten years. I flush it once a year to remove the hard water sediment and that’s all that has ever been required. The point is the technician, for whatever reason, sold the customer something they did not need.

Gary
15 days ago

So now the guy has an anode rod in a water heater that doesn’t require one.

Drew
15 days ago
Reply to  Gary

I think the tech just made the suggestion. It doesn’t sound like a rod was ever installed. Also, I see some statements here that the question wasn’t answered. I don’t understand that- the question that the poster asked was whether or not an anode rod was necessary in his Atwood equipped motor home. That question has been answered in detail here.

James Shoe
12 days ago
Reply to  Drew

“The technician said it would be beneficial to have an anode rod in our tank and he installed one.” 

Bill Coady
15 days ago

I think he did answer the question by explaining the difference tank and manufacturing processes. The two manufacturers have different solutions. Atwood engineers say none needed because of their choice of tank materials. Suburban engineers design calls for one. I’m not an engineer so don’t know the answer but could the addition of a Magnesium anode rod in an Atwood aluminum tank have unintended consequences over the long term?

Bill Coady
15 days ago
Reply to  Bill Coady

A quick web search seems to indicate that magnesium and aluminum are compatible in general. I’d still opt for deferring to the engineers at Atwood and Suburban and take Dave’s advice about flushing regularly to heart.

Dave
15 days ago

In an Atwood, there should not be an anode rod. Placing one will cause a galvanic reaction between the aluminum tank and the steel plug end of the anode. This will seize the threads and you may end up replacing the water heater tank. Same goes for “Hot Rodd”and other similar products as add-ons.

HappyCamper7424
15 days ago
Reply to  Dave

I attended a seminar on hot water heaters presented by a rep from Dometic (they now own Atwood). He said the same thing, installing an anode rod in their water heater is problematic.

Tom
15 days ago

You didn’t answer the question. Behaving like a politdician.

Bruce
15 days ago

I flush it by turning citywater back on and off a few times and let it drain each time.

Bob Palin
15 days ago

You didn’t answer the question.

tom
15 days ago

I used the flush tube on my Atwood. Amazed at the large amount of “stuff” flushed out.