Monday, December 4, 2023


Ask Dave: My RV’s water heater has problems. Is it still usable?

Dear Dave,
I purchased a 2008 SnowRiver camper in August. When I winterized the camper I discovered that the anode had never been changed and was bare wire, with a lot of white sediment at the bottom of the tank. I used a spray wand to flush the tank and at that time I noticed a lot of black flaky paint (porcelain?) washing out of the tank. I looked inside the tank with a camera and saw places that were white where the black had flaked off. How do I know whether my water heater is still usable? I have heard that the concern with an unchanged anode is rust in the tank, but I could not see inside well enough to know whether there was any rust. —Toni

Dear Toni,
If your water heater has an anode rod, it is probably a Suburban since the Atwood model has a stainless steel tank and does not use one. The Suburban tank is steel with a porcelain lining similar to a residential water heater. The electrolytic action in the operating of the water heater will attack metal components and require protection of the tank. Typically, the original anode rod was made of magnesium and acts as a sacrificial metal for the galvanic corrosion. However, if the rod becomes deteriorated, the tank will start to corrode. Here is a photo of a new anode rod.

Water heater was probably not maintained previously

From your description of the sediment, anode being just a wire, and the black flakes, it’s obvious the water heater was not inspected and maintained by the previous owner. I would also be very apprehensive about how the unit was winterized as the anode rod is the drain plug. Surely the previous owner would have had to remove that and noticed the deterioration of the anode.

I applaud you for the inspection with the camera in the tank and desire to diagnose the tank. Since you stated the anode you removed looks like a wire, I would assume the tank has been compromised and the black flack pieces you are seeing is the porcelain coming off. The white sediment is most likely the calcium and lime from hard water. Since the drain hole is typically higher than the bottom of the tank, it will settle at the bottom unless flushed out, as you have done.

How do I know my water heater is still usable?

That is a very good question. In my opinion there would be three areas I would be concerned about: heating efficiency, water quality, and leaks.

Heating efficiency

The Suburban tank is steel and lined with porcelain, which they claim creates a superior insulation to keep the water temperature warmer longer. Depending on how much of the porcelain insulation has flaked off, how long will the tank retain temperature before the water heater will have to cycle again? Plus, how much of the sediment settled to the bottom of the tank and hardened? You did not mention if it’s a standard LP water tank or dual 120-volt/LP. However, the flame and heating element are located near the bottom of the tank so the more sediment, the less heating efficiency.

Water quality

With the porcelain flaking off, the steel parts showing will rust. Who knows what other minerals could be inside that tank. I would suggest filling it with water and let it set for a day or two, then get a pack of Safe Home, a water testing kit, from a home improvement store and test for the various minerals and impurities.


Again, with all the porcelain flaking off and thin steel exposed, I would be most worried about the unit leaking eventually.

It would probably be worth the effort to remove the pressure relief valve to get a better look from the top with some light. This will probably be hard to remove as I’m sure it has never been removed prior and is hard to get at. A crow’s foot is typically a good tool to use; however, I usually use channel lock pliers.

Above, you can see a Suburban model that has a metal drain plug with some rust. The Atwood is plastic… or at least it is from the factory. Notice the pressure relief valve at the top—hard to get a wrench in there.

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.

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Dave Solberg
Dave Solberg
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. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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Pierre Woody (@guest_172811)
1 year ago

I would be FIRST concerned with leaks, if it’s leaking then it’s done.

DW/ND (@guest_172594)
1 year ago

I have an Atwood water heater with aluminum tank. It’s electric and propane. I also have an “expired” anode rod with a short wire end. I keep it in my service parts bag as a backup plug to the plastic factory plug. I have used it a couple of times and wrap silicone tape around the threads. I flush a lot of white residue from the tank every spring and fall – calcium, magnesium I guess – it is from well water.

Thomas D (@guest_172592)
1 year ago

While vacationing in Florida the water heater stunk like a skunk. I removed the anode and put in a drain valve
No more stink and because of the valve, easy flushing of the tank. No anode? Tank still going strong 19 years later. Flushing makes the difference.

Bill (@guest_172557)
1 year ago

My anode rod broke off at the plug, no way to remove it. Since Dave doesn’t seem to know aluminum from stainless maybe some of you guys can help. Will the old rod laying in the bottom of the tank cause any problems as it deteriorates? I will of course be flushing the tank every couple of months.

WEB Webster (@guest_172650)
1 year ago
Reply to  Bill

Do not worry about the rod, just do the regular flushing.
Stainless steel tanks? Porcelain as a thermal insulator? I have had it with his articles and the many errors.

Bill (@guest_172664)
1 year ago
Reply to  WEB Webster

Thanks WEB!

GWM (@guest_172737)
1 year ago
Reply to  WEB Webster

Yea, all the ones I have owned have been Atwood heaters. I had to replace one with a new one as the previous owner didn’t drain it and the bottom of the tank split(aluminum). It was wrapped in fiberglass insulation in side of a cardboard “box” as was the new one I purchased. Junk that old one! Not worth your health or damage that will likely happen in the near future.

tom (@guest_172547)
1 year ago

Remove and replace. Just another post on the importance of “reading the book.”
Good luck with your fun job.

Thomas Kneib (@guest_172535)
1 year ago

The Atwood heater is NOT made of stainless steel. It is made of aluminum.

Jesse Crouse (@guest_172510)
1 year ago

From a plumber- Pay me now or pay me later after it has leaked all over the unit and you have to deal with the mess and damage. Sounds like it is on it’s last leg. I would do it now- cheaper and no damage to your unit.

Bob p (@guest_172528)
1 year ago
Reply to  Jesse Crouse

Yes they are less expensive than replacing saturated flooring in the unit plus every other place the leaking water drains to.

Joe (@guest_172622)
1 year ago
Reply to  Jesse Crouse

Be proactive not reactive. One will always never have issues at a good time.

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