Black Soot in bathtub

Discussion in 'Water Heater Forum, Tanks' started by supermattthehero, Apr 23, 2013.

  1. supermattthehero

    supermattthehero New Member

    Messages:
    78
    Location:
    virginia
    I've been getting black soot coming out in the bathtub when the hot water hasn't been used all night. It doesn't appear to be broken-up rubber. It is very fine, black, and the large pieces will break up and dissolve if I poke them with my finger. It will smear on the tub.

    I have a gas hot water heater. Does this mean it's on its way out? It's been like this for months now.

    EDIT: I should add that I also get them in the bathroom sink. It is not limited to the bathtub.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,833
    Location:
    NW Ontario, Canada
    It is probably from the anode rod disintegrating. It could also be manganese but I doubt it.
  3. supermattthehero

    supermattthehero New Member

    Messages:
    78
    Location:
    virginia
    What do I do about it?
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,270
    Location:
    Cave Creek, Arizona
    It is magnesium sulfide, often caused by a reaction between the anode rod and soft water. Change the rod and try to flush the remnants out of the heater, which may not be possible.
  5. matrazar

    matrazar New Member

    Messages:
    1
    Location:
    Houston
    I recently replaced my gas hot water heater 2nd floor above master bathroom.
    I now have black soot appearing in my tub. since this is a new tub I am guessing I have magnesium sulfide in the pipes is there anything I can use to flush this out and clean the lines?
  6. supermattthehero

    supermattthehero New Member

    Messages:
    78
    Location:
    virginia
    Update: The problem wasn't the water heater, it was the Sharkbite flexible water heater lines I had used. Replacing them with conventional flexible copper lines solved the problem. Here is a link to someone else who had the same issue:

    http://www.kcsr.org/showthread.php?t=84485
  7. Terry

    Terry Administrator Staff Member

    Messages:
    14,783
    Location:
    Bothell, Washington
    So the O-ring on the Shark Bite flex connector failed?
    There is a lot of heat right off the water heater.
  8. JerryR

    JerryR Member

    Messages:
    234
    Location:
    Florida
  9. poe

    poe New Member

    Messages:
    3
    Location:
    Ohio
    I have the same problem but all of my lines are copper. Running peroxide through my tank cleared it for about a week. I pulled my anode rod to find it covered with a thick layer of the black slime.
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