Rotten Egg Smell

[KestrelBuck]

Hi All,

Why does my "fresh water" smell like rotten eggs and what can I do about it?

Thanks in advance for your replies.

[Tempest245]

It's usually Sulfate in the water supply or hydogen-sulfide.

here's a good summary:

Hydrogen Sulfide, Rotten Egg Odor, Sulfur, Rotten Egg Odor in Water

[MarkJ]

Sure its the water and not the sink drain?

[Tempest245]

Yes, It could be the lines...if the fresh water you put in, doesn't have a sulfer odor to it...

[bchaps]

The rotten egg smell is common. I've had to clean my lines at least once each year so far. Here is a link to the procedure.

Bill

IP Home Port - The Official Website For Island Packet Yacht Owners Since 1998

[peghall]

Is it both the hot and cold water, or only the hot that stinks?

If both, recommissioning the system should fix it. We had a long thread about how to do that just a few weeks ago, so it shouldn't be too hard to find.

[smurphny]

If it's the hot water, it's likely anaerobic (Divibrio Sulfurcans) bacteria growing in the tank and lines. Give it a good dose of chlorine or some commercial shock treatment and it'll be gone. This happens to home (well) water systems on a regular basis and people mistakenly attribute it to smelly water coming into the house. The link explains a bit better (but they're trying to sell you stuff).
http://www.waterheaterrescue.com/pag...r-heaters.html

[peghall]

Actually, more often than not, a "rotten egg" odor in the hot water only is due to a failed anode in the hot water tank.
Anodes are included in the water heater of glass-lined steel tanks to protect the inside of the tank against corrosion from acids in the water, stray electrical currents, etc. Glass lined tanks, when the water heater is being built, are heated up red hot. Then glass powder is sprayed inside the tank and it adheres upon contact. However, it doesn't cover every single crack and crevice inside the tank - it should, but in actual practice, it doesn't. The purpose of the anode is to protect those spots inside the tank that have not been glass-covered from rusting away prematurely. The anode is eaten away, rather than the tank being eaten away. Kind of a backup to the glass lining.

The anode is a magnesium rod, about 3/4" in diameter that is attached to the inside of the hot water "out" nipple, via a plastic coupling. It is electrically isolated from the fittings and from the tank. It extends all the way across the inside of the tank, stopping just short of the other side. There is an iron rod in the center of the magnesium that supports it, the iron being stronger than the magnesium. As the magnesium is eaten away and the iron rod exposed, there's a chemical reaction between the water, the iron and the magnesium that causes the "rotten egg" smell. Replacing the anode and flushing out the tank will usually make the foul smell go away.


Only glass lined water tanks have replaceable anodes....the only marine water heater that I know of which does is Raritan, but may be others. Most marine water heaters have anodized aluminum or steel tanks. That makes 'em a lot cheaper than glass lined tanks, but when the anodizing wears off, the only cure is a new water heater...which wipes out the cost saving.

[nigelmercier]

Originally Posted by peghall

The anode is a magnesium rod, about 3/4" in diameter that is attached to the inside of the hot water "out" nipple, via a plastic coupling.

You learn something new every day ...

[Patrick_DeepPlaya]

Originally Posted by peghall

Actually, more often than not, a "rotten egg" odor in the hot water only is due to a failed anode in the hot water tank.
Anodes are included in the water heater of glass-lined steel tanks to protect the inside of the tank against corrosion from acids in the water, stray electrical currents, etc. Glass lined tanks, when the water heater is being built, are heated up red hot. Then glass powder is sprayed inside the tank and it adheres upon contact. However, it doesn't cover every single crack and crevice inside the tank - it should, but in actual practice, it doesn't. The purpose of the anode is to protect those spots inside the tank that have not been glass-covered from rusting away prematurely. The anode is eaten away, rather than the tank being eaten away. Kind of a backup to the glass lining.

+1 on the anode... this was one of the initial problems we discovered on our own boat

[peghall]

Btw...the instructions for recommissioning the fresh water system are in the thread "Cleaning the fresh water tank" which was started around the 15th of May.