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DonBaja's avatar
DonBaja
Explorer
May 05, 2013

Water Heater Clean Out - White Powder

I did my annual Suburban Water Heater anode replacement clean out and was amazed at how much of the white powdery crud can accumulate in only a year with little RV usage. We live in a very hard water area but I usually fill 'er up with our softened water.

What is this white stuff - calcium?

Is this a typical occurrence when changing anodes?
Class A

6 Replies

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  • Chris_F's avatar
    Chris_F
    Explorer
    May 06, 2013
    I suspect it's aluminum oxide, the corrosion product from an aluminum anode rod.

    Got any left? If it's calcium scale, calcium carbonate, it will dissolve in vinegar and fizz like an Alka-Seltzer tablet. Aluminum oxide also will dissolve in vinegar, but it won't fizz.
  • havasu's avatar
    havasu
    Explorer
    May 05, 2013
    If you talk to a local plumber, they will tell you of household water heaters that despite being empty of water, are so heavy that they need 2 people to get them out of the house. They can be 1/3rd full of calcium deposits after 10 years of constant use.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    May 05, 2013
    Yep pretty normal.....especially AZ water OR any area that has 'hard' water

    THAT is why every RVr should clean out their water heater tank regardless of Brand.

    Minerals in water have a tendency to 'collect' especially when heated.

    The use of 'softened' water helps.

    And IF heavy build up, doing a vinegar soak/flush may be needed.
  • past-MIdirector's avatar
    past-MIdirector
    Explorer
    May 05, 2013
    It's the same build up you'll find if you drain and flush your home water heater. It's in almost all water heaters and is normal from the chemical reaction of the water being heated.
  • tmmar's avatar
    tmmar
    Explorer
    May 05, 2013
    Not sure if it is calcium but I get the same residue and as far as I know, it is normal. I just flush out as much as I can when I change the anode.

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