That rotten egg smell from the water heater

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Luddies

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Jul 8, 2016
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I am pretty new to the world of RVing and will no doubt have lots of questions/issues/cries for help coming in the near future.  Currently it is the rotten egg smell coming from the hot water heater.  We had experienced it in the early summer and followed the welcome advice from the forums.  I drained and flushed the water heater and gave it a good dose of vinegar with water (I didn't have any hydrogen peroxide on hand), letting it sit for a while before draining it.  Then we ran a good bleach/water mix through the storage tank and lines, filling the water heater with it as well.  Everything smelled great but today, as I was readying the motorhome for its first trip south I turned on the water heater to make sure everything was working well and when I turned on the hot water taps out came hot water accompanied by the dreaded rotten egg smell. Any suggestions out there for what steps I missed or for what perhaps I should have done?
 
Peroxide will work better but both are a short term fix. If you have a magnesium anode rod in the heater you may try aluminum/zinc if you can buy that part.

Are you per chance leaving it stored full of water with your fresh tank filled for extended periods?  Just wondering if maybe the smell is water borne from stale water sitting in the heater and the tank.  Sitting water likes to grow bacteria. 

Well, that is my best guess on this. Good luck with the solution. Smarter people than me may help a lot more with this issue.
 
How long did you leave the bleach mixture in the system?  I usually leave it overnight. In fact the last time I santized, I left it in the tank and lines for a few weeks because I wasn't going to camping for a while. 
 
Forget the anode rod - odds are you don't have one (Atwood heaters do not use them) and they don't cause or prevent odors anyway.

You need to sanitize the entire system again, heater tank, water lines and fresh tank.  All at the same time - this cannot be done in stages.  Use a chlorine bleach or peroxide solution of appropriate strength to kill bacteria. 

Why again? Either you missed one bacterium on the first pass or the water source you used since had more of the little critters and recontaminated your RV system. They aren't harmful to humans, but the odor is obnoxious.
 
I don't know what RV you have, or how it is equipped. When sanitizing, don't forget to run the bleach water through the outside shower, low point drains, ice maker, etc. Anything that the freshwater system feeds must be sanitized. When I do mine, I use a 1/4 cup of regular bleach to 15 gallons of water, and let it sit for 24 hours.
When using vinegar in the water heater, fill the heater with the vinegar, heat it up and let it cool down 3 or 4 times. After last cool down, pull the drain plug and then flush the water heater tank out well with a cleaning wand.
Another thing is does the source of water you're using have sulfur in it? That can cause a freshwater system to go "rotten" too.
 
I have an aluminum hot water heater that does not have the anode.  I removed the drain plug and installed a valve.

After every trip I drain the heater and fill with fresh cold water and a teaspoon of bleach.

Then before next trip I connect to city water and flush system via the low point drains and then ready to go.
 

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Cleaning only the heater tank runs the risk of exactly what happened to Luddies: the bacterial problem comes back in a few days or weeks.  You really need to do the entire water system, even though its the warm water in the heater where they really thrive. Odds are the critters are throughout the system, just waiting for a nice warm bath to get going again.

I notice that Dutcheagle's procedure involves removing the PT valve. That's not necessary if you pump the sanitizing solution through the entire system, which includes the heater tank and all the lines.
 
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