Hydrogen Sulfide!

After two minutes of running the shower and sink in the bathroom the smell of rotton eggs was strong. After five minutes it was very nasty to be in the bathroom. The electric water heater was unplugged.
The contractor performing water sampling and buyers noted no smell when running cold water only, indicating the hot water heater as the source of the problem.

The source can be bacterial infection of the tank, a reaction between water chemistry/minerals and the scarificial annode material and I don’t know what else.

I’m desribing the situation, stating that the problem sources mary vary and recommending that the water heater be replaced.

I have smelled that many times on water heaters that have not been
in use for a long time. After running the water for a long while, it
seems to clear it out sometimes (as long as the anode tube is not defective).

Not sure I would ever want to drink any of it… :slight_smile:

Home had been empty for only 2 weeks. Apparently it’s non-toxic, but I don’t think I’d drink it before going out on a date. Not if I liked my date.

This explains it well. We had this in our last home and once a year or so I would shut of the feed to the home . I had a 12 volt pump from a motor home open hot water tap and pump into the cold water tap a pint of laundry bleach then a gallon of water to be sure the bleach got into the water heater…
. I then shut all the valves and opened the water feed to the home and it would be fine for many months .
… Cookie.

No pump and if there is a vegetable sprayer you can siphon it into the tank takes longer though and you need to drain out the bottom of the tank.

Hi Kent,

it may be non toxic, but it is highly flamable, there are many stories around concerning explosions of water heaters and dishwashers due to this.

BTW while we’re talking about the bad smell, pull my finger :mrgreen: :mrgreen:



This happens at my home. I am on a private well. I change the annode rod every 2 years. I also shock my entire system 2 per year. This makes the water taste and smell fine.

There are some small towns in Missouri that have that rotten egg smell in their water most of the time. The whole town’s water smells like that. What causes that problem?

Don’t usually need to replace the whole heater, just the anode rod.

Might want to research a bit before recommending the whole heater be replaced.


More than likely this sulphur smell will not require a new water heater on a vacant home. When the water heater is not in use, hydrogen gas can accumulate in hot water systems that have not been operated for a period of time. Under these adverse conditions, (as Gerry stated) this hydrogen gas can cause fires at faucets and explosions at water-using appliances.

If a new home has been vacant for more than a few days, recommend your client’s to flush the hot water system by turning on all hot water faucets and letting them run for several minutes. The smell should dissipate.

Caution: Do not use the hot water faucets near any open flames (cigarettes, candles, etc.) and do not use any hot-water-using appliances (dishwasher) or nearby heat-producing appliances (dishwasher, cook top, etc.) until the hot water system has been flushed completely.

If you have a multi-story residence, start turning on hot water faucets in the highest floor first and work your way down to the lower floors.

If the smell doesn’t go away, then it could be bacteria in the water reacting with the anode rod which can produce a “rotten egg” smell and make the water smell and taste bad.

To correct this problem you must change the old magnesium rod for an aluminum one. Then you must drain and flush the water heater and every hot water line. You must also remove and clean every aerator screen. For those that do not know where the anode rod is… The anode rod is located under the large hex nut on top of the water heater.

Remind me not to pull your finger… :frowning:


Where’s this finger been?


I let it run for a while. The smell didn’t fade and was real strong. They had a short time before they closed and didn’t really have time to experiment. It can be everything mentioned here and maybe more and I did tell them that. I think next time I’ll just recommend a specialist evaluation.

Here’s my report comment:

Odors, turbidity, or discoloration may occur from the house water supply piping during prolonged vacancy or other specific conditions such as but not limited to contaminants, sacrificial anode failure or bacterial growth. In the event flushing, allowing both the hot and cold water to run for a prolonged period of time at all fixtures and the water heater(s) does not resolve this condition consult a qualified licensed plumber for further information and any required appropriate action or repairs. Bottled water should be used for drinking and food preparation until this condition is resolved to your satisfaction.

We had a home that we remodeled and had the same smell in the water. The hot water smelled really bad and we could not detect it in the cold. Thought it was the hot water heater but it was not. I contacted the people who put down the new well and they seemed to think it was the well. So this is what was wrong.
The well had a bacteria that would build up over time. It caused the sulfur smell. So the fix was easy. You could put a chlorinating system in or do what I did. Every month I would pour about a pint of bleach into the well. It was not even enough bleach to smell and it would kill the bacteria. Hope this helps. Your report sounds fine.

Thanks Barry. Dug this up from the archives.
It’s sad to see a post from Gerry B .

Yeah it is. I run into those every now and then too.

My opinion of what is most likely is. :slight_smile:
Not a water heater issue, rather a water chemistry issue.

Then consider the water heater your Bunsen burner! :wink: