Anode Rod for Gas Hot Water Tank

Ken Foley asks,

I had to replace a 4-1/2 year old Bradford White, gas-fired hot water heater (50 gal.). It was leaking. Plumber said this was due to a totally destroyed anode rod and this was due to my installation of a Culligan water softener system about 3-1/2 years ago. Plumber says that the tank had an aluminum rod and what's needed now is a magnesium rod. Culligan suggests switching out the rod or just removing the rod and plugging the opening for the rod. The latter voids the warranty, however. Plumber says BW installs aluminum rods in N. TX, not magnesium, even tho' BW's website says that they install magnesium rods in all of their models. Needless to say, I am confused about what to do. $-1/2 years on a hot water heater is totally unacceptable. We really like treated water because our water here is extremely hard. Can you help me? Thanks.

Our Answer

On your behalf I reached out to the experts Rheem who offered a very comprehensive Technical Service Bulletin on Anode Rods, Cathodic Protection and the Porcelain (glass) Lining.

Rheem notes in their document that “the most important factor in the life of the anode rod is the water chemistry, the hardness or softness of the water. Water softeners contribute to the change in water chemistry. Indirectly, softened water acts to reduce the service life of the anode, since its current demand becomes drastically higher.

Since you’re using a water softener, annual inspection of the anode rod is recommended. You should also plan to replace the anode about every 2-1/2 or 3 years under the conditions noted above, and also be sure to properly maintain the water softener system.

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Ken Foley

Thanks very much for your answer to my question. To close the loop, my plumber called today to say that he was incorrect. BW does in fact use magnesium anode rods and that’s the metal I need, apparently. Perhaps the previous water heater had an aluminum rod, but I don’t know for sure. I will follow your advice to have this new rod inspected every 2-1/2 to 3 years, and replaced, as needed. This issue shouldn’t be a black art, but I have to tell you that I’ve received so much contradictory advice on it that it’s mystifying to me. Shouldn’t be that way should it? I blame Culligan more than anyone because they never said a word to me about the effect of softened water on the hot water haeter when they sold the system to me. Thanks again.

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