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I hear conflicting information on replacing the anode bar on a water heater or not since the water heater will be replaced anyway.

Should the anode bar be periodically replaced? Why? How often?

Chris Cudmore
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mdpc
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2 Answers2

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The anode rod corrodes over time, and once it does, cold water is not properly delivered to the bottom of the heater which results in luke-warm water. The simple answer is that it should be replaced as-needed.

On some water heaters, this rod is part of the cold water supply, so replacing it requires disconnecting the tank which can be a fair bit of work. Some heaters have what is known as a sacrificial anode rod that is independent to the intakes and exists solely to protect the rest of the water heater from corrosion - usually this one is easier to remove and replace.

If you have plans to shortly replace the whole tank, I would not replace the rod unless you suspect it is already corroded and causing problems.

Steven
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  • I believe the anode rod is separate from the cold water supply pipe in most hot water heaters, so there isn't a good way to know when it needs replacing, beyond pulling out and inspecting the old rod. – BMitch Jan 02 '13 at 21:40
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    They are known as combination rods when they are connected the outlet - common in older tanks. Most modern tanks have separate rods - some even have more than 1! – Steven Jan 02 '13 at 21:43
  • Is is standard practice to replace this part or just forget it and let the water heater eventually die? – mdpc Jan 02 '13 at 22:06
  • Typically I'd say they are replaced every 3-5 years, and it is very common to replace it a couple times throughout the life of the tank. The rod is designed to corrode so that the tank doesn't! – Steven Jan 02 '13 at 22:46
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    @mdpc both are standard practices. Some folks replace them and extend the life of the heater. Many folks don't and just get new heaters every 10 years or so. – DA01 Jan 03 '13 at 15:58
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The Anode rod is a sacrificial element that is there to prevent tank and water system corrosion. It's life is dependent on the type of water you are dealing with. Your tank's life is dependent on the rod having enough active material to erode away (cheap stuff like zinc or aluminum) through galvanic corrosion.

If you don't mind the expense of replacing a water heater every 3-5 years, and possibly your hot side plumbing somewhere down the road just ignore the anode rod.

One thing you don't want to skimp on is flushing the water heater regularly to remove particulate, rust and cast off spent anode rod material. If you have a copper water system, the junk can get out into the hot water piping where it can cause spot corrosion and nasty pin holes, destroying plumbing that could have lasted 40 or more years, all for the lack of a little maintenance. Been there on that one as well, it's far more expensive than the water heater and magnitudes more expensive than those damn rods that are there to prevent it in the first place.

Proper life span says that if you can see the iron core rod in the anode, it needs to be replaced. Typically, for our water here, we can get 10 years on a water heater with about three rod replacements.

Fiasco Labs
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  • Heck, I prematurely replaced my tank that was about 20 years old, and I wouldn't be surprised if no one ever even flushed the thing. This is one of those cases where the answer is "it varies, significantly." – BMitch Jan 03 '13 at 03:21
  • Yep, that it does. The water here eats stuff up. Ignore it at your peril. So, check the rod, check with local people knowledgeable about water system maintenance in your locality and work out your maintenance plan from there. Hence the first sentence in the answer. – Fiasco Labs Jan 03 '13 at 03:30
  • In fact, the next time I have to pull the pump, I'm going to post a picture you'll find interesting... – Fiasco Labs Jan 03 '13 at 03:36
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    Pump... would that be well water? If so, I'm guessing those will damage the pipes faster than a municipal supply. – BMitch Jan 03 '13 at 12:14
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    Yes, it's well water. One advantage of being on the municipal supply, they have to preserve their pipes, so yours get the benefit as well. – Fiasco Labs Jan 04 '13 at 03:00
  • Does the temperature of the hot water impact the lifespan? – cmcginty Dec 07 '15 at 20:25
  • Given that chemical reactions occur faster at higher temperature, yes. By how much, I really couldn't tell you. – Fiasco Labs Dec 07 '15 at 20:36