Anode corrosion

The Tank Anode corrosion

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    If your anode is being attacked, you have to determine what is attacking it and correct the problem before replacing the anode.

    The Hydrogen Sulfide odor is usually caused by Sulfate Reducing Bacteria attacking the anode.

    If you have a private well, you have to treat the well. If you have city water, you have to find out where the bacteria is coming from. This is usually from bacterial regrowth in the distribution system after treatment.

    Both the hot and cold water plumbing has to be treated. Just replacing the anode does not do anything about the source of the problem.

    The only way this issue will be resolved is for the homeowners to work together towards that goal.

    Is anybody interested in resolving this matter?



    I’m interested in resolving the smelly water issue. I have tried everything on this list:

    *Hydrogen Peroxide

    *Bleach Chlorine

    *Magnesium Anode Rod

    *Aluminum Anode Rod

    *Aluminum/Zinc Anode Rod

    *Powered Anode Rod

    *Water Softner ON & OFF line

    *Raised temperature of WH also

    And still smell returns within 24 hrs or less! The water heater is an AO Smith ProMax GCV-50 200/201 series. New home purchase in June 2010, municipal water and only get the smell in the showerhead closest to the water heater. No smell in cold water. This water heater has an aluminum hex head anode from factory. The factory states that there is only one anode in this model. I can’t confirm this because the heater does not have flex tubing on the hot water nipple. The spec sheet, owner’s manual, and service manual only reflect one rod. What do I do? My wife is really after me on this!!

    Thanks in advance for your help.

    Randy Schuyler

    If you only have odor in one place, that means it is not the water heater. I really regret that you’ve changed all these anodes. There are other posts in The Tank like this, where it turns out to be bacteria in the sink overflow, or a sewer issue. Tell us more about this situation and we can probably resolve it.

    Aluminum/zinc anodes and power anodes are designed to deal with the sulfate-reducing bacteria that Hotrod talks about, but if there is some other odor from some other place, treating wells and water heaters and changing anodes and such isn’t going to solve it.

    Interestingly, I used to tell people to add hydrogen peroxide when they put in zinc or electric anodes, to kill bacteria in the system, but mostly I started forgetting. It doesn’t seem to make any difference. The smell goes away as soon as the sacrificial anode that is causing it is removed.

    And Hotrod: the only time those bacteria cause a problem or are even noticed, is when they react with a sacrificial anode. You don’t need to do the extensive measures you suggest if you can just fix that part. Powered anodes almost always work. And treating your well is only a temporary fix because you can’t treat a whole aquifer.

    By the way, the bacteria don’t attack the anode. They react with it. I don’t think they speed up the sacrificial process any by doing that. All this stuff about attacking anodes…anodes are THERE to be attacked. They are consumed to keep a heater from rusting. It’s just that sometimes there are side effects to that process.

    Randy Schuyler


    I’m open to suggestions, the shower stall water only smells when someone is taking a shower. As soon as the stall dries up, no smell. I have had my nose close to the drain and haven’t smelled anything when shower not in use. Should I do the smell test while taking shower? The shower is used everyday so if there happens to be a p-trap under there, I’m sure it’s not dry. Our maid reports the smelly problem when she is cleaning the shower stall glass, walls etc..using hot water.

    Last night we took a shower and had not noticed the water heater pilot had extinguished, the water temp was not as hot and the WH did not kick in to heat the water obviously, we had no smell. I then turned the WH back on and smell returned.

    Please help.


    Dear jhinojosa,

    We need to start tracking these water problems so I need to know what state you are in and do any of your neighbors have the same problem? I assume you are referring to a rotton egg odor in your water. What was the condition of the initial rod when you took it out and how long was it in the tank?

    Do you have any other other symptoms, such as bacteria in your toilet tank or toilet and any black or brown material coming out of your plumbing.

    The first thing you need to do is have a qualified plummer chlorinate both the hot and cold water plumbing. That means putting bleach in the entire system and letting it sit overnight. You need to remove all screens and filters, because if there is bacteria living in your plumbing, it will plug up the screens. It could also plug up your mixers in the shower. You also need to protect all of the chrome fixtures when flushing the system, because the bacteria produces a black slime that is highly corrosive and it will eat the chrome before you can wipe it off.

    You need to get more than one estimate, as some plumbers overcharge for this service. The cost can range from $200 to $800.

    The fact that the house was new in June 2010 indicates that there is a bacterial regrowth in the distribution system. This not uncommon.

    As you have discovered, changing the anodes is not the answer, in fact, the magnesium anode increases the activity of the bacteria, and a water softener makes it worse.

    I am sure you will have more questions and if you would like to discuss it over the phone, give my your phone number and I will call you.




    Dear HotRod:

    Q: We need to start tracking these water problems so I need to know what state you are in and do any of your neighbors have the same problem? I assume you are referring to a rotton egg odor in your water. What was the condition of the initial rod when you took it out and how long was it in the tank?

    A: Texas * neighbors don’t have the problem * rotten egg odor * initial rod aluminum white cottage cheese like particles * original rod since late 2009

    Q: Do you have any other other symptoms, such as bacteria in your toilet tank or toilet and any black or brown material coming out of your plumbing.

    A: No

    How do you chlorinate the cold water?

    Randy Schuyler


    Please don’t spend any money or do anything until Larry Weingarten has a chance to troubleshoot this. He is very, very good at this.

    If the hot water only smells bad in one place, it can’t be the water heater at fault. If it were that, you’d have rotten eggs at every faucet. For that matter, ARE you talking about a rotten egg smell or something else? That could be important.

    So often, when people say “My water smells,” we tend to assume that it smells like rotten eggs because that’s a very common problem. But occasionally it’s something else, so we go down a long track without really understanding each other.

    I’m not happy that I sold you a powered anode that didn’t solve a problem. The product is still a good thing to have if you’re using a water softener, as it doesn’t wear out, but that’s not why you bought it.

    As to Hotrod, I already warned him in private that he could post as long as he wasn’t advertising a product or service. But I’m much troubled by him giving you advice to spend money in a certain direction, and even more, that he’s asking for your phone number. Nobody has ever done that in this forum and we’re heading for 3,000 topics.

    Hotrod, on just what grounds do you base all the things you’re saying about odor issues? They fly in the face of everything we’ve learned. This forum is meant to be a place for the free exchange of ideas. Mostly I don’t censure anything except advertising and crude language.

    So just where do your ideas come from? I think you need to answer that before you make any more posts like the preceding one.

    Randy Schuyler


    Personnal experience.

    Randy Schuyler

    That answer is unsatisfactory. Please don’t post anything further like this in this forum.

    Randy Schuyler

    Larry Weingarten

    Hello: Reviewing this discussion, the facts seem to be:
    You get odor only in one shower stall.
    You’ve tried everything in the heater thinking it is the source of odor.
    Odor is affected by running the water.

    As Randy said, unless the odor is at every hot tap, the problem is not in the heater. This leaves the main suspect which is the drain/sewer/vent system. There is (or should be) a vent pipe near the shower and this pipe usually goes up and out the roof. There is a newer device called an “air admittance valve” that allows air into the drain system as needed, but it’s less likely you have one of these. If you have steel or cast iron drains, it’s quite possible the vent pipe has rusted through and is leaking gray water/sewer gas. If there is a crawl space, some lucky person gets to crawl down there and have a good look. If there is a slab, the only trick that comes to mind is to climb up on the roof and pour some mint oil down the correct vent line, then go inside the shower and see if you can smell any mint. The test for new systems is to plug off the sewer and fill the system with water. It can be a pain to do, but water always leaks where it can. Another inconclusive but easy test is to put plastic down to block the drain and then run water. Any smell? If not, arrows point to the drain lines.

    Do let us know what you find 😉

    Yours, Larry


    I have shocked both the well and the hot water heater numerous times after replacing the hot water tank. Never had a issue till I changed tanks. Now every six weeks the water goes sour. I shocked the pipes the faucets the well and everything in between so I am at a loss at this point.

    Randy Schuyler

    The thing about well water is that what’s in the ground can change over time. Also, an older heater with a nearly consumed anode will smell less or not at all, but when you replace it, and have a brand new anode, the problem arises.

    If you’re not softening, switching to an aluminum/zinc anode will probably fix it. If you are, though, you ought to get a powered anode. Other solutions are tankless heaters and the Marathon, a plastic-lined heater with no anode, but both are expensive.

    Randy Schuyler



    As I told you over the phone, I have been through all of this before. Replacing the anode on a regular basis or putting in a different anode is of no value if the problem is bacteria in the water. Chlorination and increasing the water temperature only lasts until you use the water again.

    You need to have a plate count done on the water where it comes into the house. This may or may not give you a clue as to what is going on. This only tells you if there is bacterial activity in the water, it does not tell you what bacteria is there. We have a home here in the development that has a low plate count, but they have black slime coming out of the shower and problems with iron bacteria.

    It was a pleasure talking to you, as you have obviously done your homework. It will be interesting to hear what your water supplier has to say about the problem.

    Keep in touch,




    You can go online and check out Sulfate Reducing Bacteria in private wells. Unfortunately, if what you have done has not worked, you may have to drill a new well.



    That makes absolutely no sense. Why would there be a issue with my well when everything worked great for 13 years? I change out water heaters cause it went bad finally and now I have stinky water only at the hot water. Why not at the cold also? Your theory is not good and has no basis.

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