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I have an electric water heater that gives the water a sulfur smell. It is only from the hot water.

I have heard that changing the anode in the unit can help. If this is the case, what material should the anode be made of? Is there another solution to this problem?

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up vote 4 down vote accepted

The smell is created when natural sulfates found in some water mix with certain micro organisms (bacteria), they produce hydrogen Sulfide (H2S).

The preferred treatment is to flush out the system with chlorination and in the process kill off the bacteria. Also by letting the water rise above 140 °F (60 °C) it should also kill off the bacteria but it is not as effective as chlorination. Also more than likely it will return without proper chlorination. Replacing the anode is a common suggestion but it rarely works as it doesn't fix the root cause of the problem. If you were to chlorinate it I would suggest adding a filter for the sulfates and UV filter also will kill off the bacteria as well.

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I wouldn't say the anode rod isn't the root of the problem. When it corrodes it creates the hydrogen part of H2S. I had an old tank that used to have this exact smell. When the Anode finally disintegrated the smell was gone. Replaced the tank (new Anode) smell is back. – JohnFx Oct 28 '14 at 2:22

A sulfur smell is usually a sign of sediment in the tank. This is common if the tank is left on during long absences or low volume use. A spent anode can contribute to this smell, since other parts will start to corrode once the sacrificial anode is spent.

You should purge the tank by draining it from the bottom valve with the water supply and power turned off. You may be shocked by the gunk that may come out. Once the tank is empty, turn on the water (no power) and partially fill the tank allowing it to continuously drain. Repeat this flushing until the waste water is clean and fresh smelling again. the anode is often inserted in the top of the tank and can be removed with a wrench. A new one can be inserted, seal with some plumbers putty or teflon tape. Once you are satisfied you have purged and flushed the tank, turn on the water, fill the tank and run the hot water faucets to clear any remaining bad water out of the feed pipes. After all this is said and done, turn the power back on and heat the water.

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You will need a so let for the older models, or if your anode is recessed under a cap. We're draining and replacing the anode now, so we will soon know if that's the issue.

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What is a "so let"? – wallyk Nov 4 '14 at 20:05

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