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Smelly hot water tank

Discussion in 'Technical Discussion' started by Trinimax, Oct 11, 2016.

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  1. Trinimax, Oct 11, 2016
    #1
    Trinimax

    Trinimax Senior Member

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    How to prevent the water in my water heater going from smelling?

    Here is my dilemma, I have a 43 ocean which has a 20 gallon water heater, I use the boat almost every weekend for day trips and the fresh water gets cycled through quite regularly. However I may only over night once a month, and only turn on the water heater and use the hot water on those occasions. I have treated the hot water tank with strong chlorine and removed the smell, however the smell is starting to come back again. Is there any preventative way to stop the bacteria or whatever building up in the tank ?

    I have thought about leaving the water heater on while away from the boat in hopes that the high temp will reduce any bacteria, however I am not so comfortable with leaving the heater on all the time.

    Thanks in advance for any suggestions

    GMax
  2. Capt J, Oct 11, 2016
    #2
    Capt J

    Capt J Senior Member

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    Well, I wouldn't super chlorinate it. I recommend a drop of bleach per gallon of water for keeping water tanks disinfected (if you don't have a watermaker doing flushes from it), but no more than that. If you use the boat on the weekends (day trips) and have the hot water tank off. Just use the hot water side of the faucet (which should be room temperature also) for washing hands and whatever to flush water through it.

    Other option is to leave the hot water tank on, everytime you use the boat. This will help, but still don't think stagnant water should be left in there. I'm a proponent of using all systems everytime I use a boat, just so things get worked.
  3. Trinimax, Oct 11, 2016
    #3
    Trinimax

    Trinimax Senior Member

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    Thanks Capt J. I do not want to put too much bleach in the fresh water tank, as I have a watermaker that flushes from it automatically. As You say, i will need to get in the habit of using the hot water more often.

    Also, just thinking aloud here, for whenever the day comes that the water heater dies, what are your thoughts on using a tankless waterheater as a replacement.?

    thanks again for the response

    GMax
  4. Pascal, Oct 11, 2016
    #4
    Pascal

    Pascal Senior Member

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    Tank less water heater use a ridiculous amount of power. I looked into it but it s just not feasible on a boat even with a large genset and 50amp shore
  5. justold, Oct 11, 2016
    #5
    justold

    justold Member

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    replace the zinc anode in the water heater tank
  6. CSkipR, Oct 11, 2016
    #6
    CSkipR

    CSkipR Member

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    Electric tankless heaters are not worth much and certainly wouldn't put one in my boat. They use a tremendous amount of power as mentioned by Pascal. Propane tankless is wonderful but not sure if you want to use propane on the boat. Agree with justold that your zinc anode inside the tank is probably ineffective or bad.
  7. olderboater, Oct 11, 2016
    #7
    olderboater

    olderboater Senior Member

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    The most common cause of smelly hot water is the magnesium anode rod. It is sacrificial and the water may react with it, especially well water and I'd imagine watermaker water as well. Some remove the rod but it's not recommended. Best is to replace it. Actually the factory rod is generally magnesium and replacing it with an aluminum/zinc rod. Must have the zinc though, not straight aluminum.

    Oh and if you try the back flushing routine, I've heard that hydrogen peroxide is preferred over chlorine. I don't know and don't think either is generally the answer as the anode is what is creating the rotten egg smell.

    We once had this issue in a rental home with an old hot water heater and well water. That's the only reason I know anything about it.
  8. olderboater, Oct 11, 2016
    #8
    olderboater

    olderboater Senior Member

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    Actually Hubbell electric are rather nice and not too bad on power if you have three phase.

    I guess much comes down to how much hot water you require. Depends on how long the showers and how many taken. We typically have a lot more showering taking place than most systems plan for.
  9. Capt J, Oct 11, 2016
    #9
    Capt J

    Capt J Senior Member

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    +1, I agree with this. Too much power draw at once.
  10. Trinimax, Oct 12, 2016
    #10
    Trinimax

    Trinimax Senior Member

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    Thanks for the replies fellas. I did not know about the anode in the water heater. I will have to do some digging and check that out.

    with regards to the tankless waterheater, I figured they would draw too much power and you all have confirmed what i was thinking.