Hot water smells like rotton eggs

Discussion in 'General Discussions' started by hardchines, Aug 13, 2009.

  1. hardchines

    hardchines Member Forum Leader

    I am posting this topic in case someone out there has this problem or may have it in the future, this is great to know, and few do.

    Last year I installed two Geo units, these replaced old AC units, but I left my oil system intact, it is a Hydro air system, meaning in each air handler there is what amounts to a radiator that gets hot water from a oil fired boiler for heating the house with hot air. The hot water on the old system is a Amtrol hot water maker, it has a heat exchanger built in and also gets its hot water from the oil boiler.

    When I installed the Geo's I needed a hot water heater that did not need the boiler to be on, so I installed a basic GE 80 gallon electric water heater.
    after several weeks of using the new GEO. units and the electric hot water heater, I started getting small whiffs of sulfur (rotten egg) when taking my morning showers. Over the next month the odor from the hot water grew worse and by spring my wife and daughters were ready to take showers with bottled spring water.

    This was my assumption, I use about 24,000 gallons of water every 3 days for my heating system, this water goes back into the soil close to where my 90 foot well is ,the water level in my well is down 40 feet from the top, so I figured the water was picking up the sulfur mineral and my electric hot water heater was causing the sulfur to come out of the water and stink. This summer I switched back to oil for hot water, smell gone , I figured the low temperature of the heat exchanger in the Amtrol unit did not cause the sulfur to be released.

    Ok I turned off the oil and turned on the electric water heater along with the geo units two weeks ago and the oder was much, much stronger. Smelling the oder made me madder then the fact that when I went to turn on the breaker for the water heater I found it already on, the wife threw it by accident, four weeks earlier.
    I started looking on the internet for systems for controlling or mitigating sulfur in well water, I found lots of expensive chlorine adding machines and such. I tried a Google search for hot water smells like rotten eggs and found a this old house forum, someone asked the question why does my hot water stink, several questions were asked of the poster like, does cold water stink, answer no, is it a new water heater, answer yes (about a month old), same symptoms as mine. The response was "you have a bacteria growing in the water heater, it feeds or is caused by trace amounts of sulfur reacting with the water heater's sacrificial anode rod, FIX IS TO REPLACE MAGNESIUM ANODE WITH AN ALUMINUM ANODE and put some bleach in water heater for a couple of hours and you will be fixed.

    It worked I now have no oder at all, I felt posting this was worth it if even one person ever gets to benefit from it.
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    In some areas South and East of Cleveland is common. The cheap fix was just pull the anode and plug the tapping.
  3. Guest

    Guest Guest

    I had this problem and wasn't willing to remove the anode and have the WH corrode soon. Chlorine shock works for awhile.

    I ended up with:

    1) drain and flush tank
    2) replace anode with new aluminum one
    3) set temperature somewhat higher
    4) add a carbon filter
  4. geome

    geome Member Forum Leader

    Mark, wouldn't removing and not replacing the anode rod rust the tank sooner and void the warranty on the new water heater?
  5. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Isn't there an alternate anode material available for this problem?
  6. hardchines

    hardchines Member Forum Leader

    I replaced anode rod with a aluminum anode as per instructions, from this old house reply. The rod I used was actually aluminum with some zinc and tin,(it is what my supply house has) no rod = accelerated rust of inside of tank, plugging hole may be cheep for a while but will cost more in long run, takes no more effort to replace rod then to remove rod and stick a plug in.
  7. geome

    geome Member Forum Leader

    Magnesium is the only other material that I recall reading about for a water heater anode, but have no idea which material is better for this problem. Maybe there are other materials too...
  8. Looby

    Looby Member Forum Leader

    Among common metals: magnesium, aluminum, zinc (in that order
    of effectiveness) are suitable as sacraficial anodes for protecting
    iron and steel.

    Way back in my USN days (40 yrs ago) we used zinc anodes almost
    exclusively -- but zinc would NOT be my first choice in a potable water
    system. If magnesium is causing problems, I'd go with aluminum.

    Looby (ex-snipe & escaped chemist)
  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Nothing at all is good with me. You are going to get a finite amount of time out of a tank on well water anyway.
  10. hardchines

    hardchines Member Forum Leader

    For the wrong answer on what anodes to use and should you use them see Joe's answer above!
  11. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Around Cleveland

    I was out doing so I did not get back to this sooner.

    I mentioned removal of the anode rod as the fix we used then. It did not cause premature tank failure.

    I deal in H20 tanks as an expendable item. I have a fifty gal. at 40K BTUH that is nine years old. It came with a five year warranty. So now I am on barrowed, but free time until it gets replaced with a tankless.

    I do not know about the change in anode rod composition so I will listen and learn.
  12. Looby

    Looby Member Forum Leader

    Re: Around Cleveland

    Corrosion rates are strongly dependent on water quality, especially pH.
    Other components in a water system may also act as sacraficial anodes
    protecting the water tank ...or vice versa.

  13. stevecaz

    stevecaz Member


    6 years in our house and we never had sulfur smelling hot water. Then I replaced the 20 year old natural gas water heating with an electric one in anticipation of the geothermal connection. Unfortunately 3 weeks later one thermostat went bad - and suddenly we had bad sulfur smelling water. Inside the tank with one element out the other was working all the time to try and heat the water, which was only luke warm. Once thermostat was replaced and hot water was back, odor went away. Well I had to drain the tank to clear it out, but its gone.

    It seems constant heating source plus moderate temps promoted the bacteria growth, while the hot water and intermittent heating element function does not.
  14. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    With 20 years in the business I have seen little to indicate consequence from removal of the anode rod. As was pointed out other factors are involved as well.
    Unfortunately in this day and age life of the tank is a lesser concern than life of the vent motor or ignition system.
    Good luck,
  15. palandor

    palandor New Member

    I had 2 tonne Geothermal heat pump installed in October 2010 with a hot water generator and a new water heater tank. Also had a water heater timer installed at the same time. All was professionally done so I have that to fall back on if needed.
    On the old (and I do mean old) tank, there was no problem with stinky hot water, but on the current setup, it's quite annoying.
    At first, I used the water heater timer (on for 1.5 hrs per day before high usage events) and that went well until about mid december at which point the hot water was unbearably stinky. After high-heat sanitizing the tank overnight and draining it, that worked well for about 3 weeks then I had to repeat the heat/drain cycle because it stank again; this time I made 100% sure to flush the lines that went thru the geothermal HWG (there are valves I shut off to ensure the cold water was routed as intended). Since that 2nd drain cycle, I have set the water heater timer to let the tank heat water 24/7 and the tank set to about 135 F on both heating elements.
    Once again the water is stinky after about 3 weeks.
    I looked up the tank specs (AO Smith ECT 52 gallon 210 electric) and it says it already has an aluminum anode.

    I would consider the length of the piping between the heater and HWG to be normal and not excessive. HWG and water heater are about arms-length apart, so piping between them (up, over, and down) for each direction of water flow is about 15 feet. All the pipes are insulation wrapped also to help avoid pipe heat loss. The reason I put this info in here is that I thought perhaps the water is cooling off and the bacteria is breeding in those pipes more versus inside the water heater. How likely does that sound?

    At this point, I don't consider permanently removing an anode as a solution, although I would consider replacing it with something else.
    However, the only options I can see at this time are to spend major dollars and upgrade my water softener to something with UV, or to spend $850 on a RHEEM plastic lined water heater that doesn't use anodes.

    Any ideas would be most helpful. I'm about done trying to solve this on my own and flushing the tank every 3 weeks. Avoiding spending major money would be nice, but we'll be in this house for a long time (at least 15 years) so if it is a long term solution but more costly up front, I'd be interested in hearing it.
  16. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    The anode and let her run.
  17. geome

    geome Member Forum Leader

    Google "water heater rotten egg smell aluminum anode". Some results I saw were:

    Solutions to Stinky Water In Water Heaters

    Tanklets: Water heater odor

    Rotten Egg Smell from your Water Heater and what causes it.

    We have the Rheem Marathon tank that you referred to (85 gallon) with a timer. In almost 2 years on the forum, it is nice to hear about someone with a similar setup (timer), although I am sorry you are currently having problems.

    We have our timer power our water heater for about 3 hours just before morning showers, and again late in the afternoon for 3/4 (0.75) hour just to make sure there is enough hot water left for the evening. Our water heater thermostats are set at about 125 upper and 110 lower, so there is room for the DSH to do its work even if these thermostats max out during timer power on times. We use about 1 full tank of hot water per day.
    Last edited: Jan 21, 2011
  18. hardchines

    hardchines Member Forum Leader

    [​IMG] In some areas South and East of Cleveland
    .' is common. The cheap fix was just pull the anode and plug the tapping.' (Mark Curtis)

    This was the answer to my post 1 1/2 years ago from Mark Curtis, I did not agree with him then and went on my own way, I replaced the anode with a aluminum /zinc rod as suggested on other sights. It worked great for a month (about the time that sulfur bacteria takes to grow, when I pulled the aluminum rod it was 90% covered with a white sulfur bacteria slime just like the original rod. I finally fixed the problem, this is the fix, I REMOVED THE ROD AND PLUGGED THE HOLE!

    So my hats off to Mark Curtis.

    From what I understand the sulfur bacteria will eat and grow on most metals, this is why the rods are the problem, the bacteria does not grow on the glass coated steel tanks or on copper and brass, remove the rod add a cup of bleach in rod hole and put a brass plug in the hole, wait a few hours and run the hot water (electric off) to purge out the tank, problem should be gone.:)
  19. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Yes I remember this topic popping up from time to time and being lambasted for my responses:
    "For the wrong answer on what anodes to use and should you use them see Joe's answer above".:eek::eek::D

    I want to remind folks that Mark or myself and the other contractors here aren't going to experiment with different composition rods, in a customers house, until we find one that satisfies. We are going to do what we know works the very first time.
    This is not intended to discourage a homeowner from trying different rods before giving up on them as much as telling you what we are sure will work.

    ...and Palandor, thanks for taking the time to search a topic before starting a new thread.
    Good Luck,
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    Hardchines: You are making me blush, however Joe summed up the situation beter than I am able to do.


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