Posted by: Roger Gillis on February 10, 2002 at 15:36:41:

I purchased a home in Florida and had the water tested and water filters installed per the companies suggestions. My cold water side of my water system is clean and fresh. The hot water from the water heater gives off a rotten egg smell. I removed and replaced both water heater elements and drained and flushed the tank. For a short period of time, the rotten egg smell goes away, but returns in a couple of days. Had the filter company retest the water coming into my home, but the tests show no problem.
Question: Is there some type of sediment built up in my hot water heater, and if so how do I clean and flush the tank to correct the bad smell problem?

The rotten egg smell comes from the decomposed annode rod in the water heater that has been fully consumed by corrosion. It is made of magnesium and is used as a sacrificial rod to prevent the inside of the water heater from corroding. It is located on the side of the tank and is usually looks like a 1" hex plug. They are usually really, really, tight; so use a six sided socket and a 1/2" breaker bar to break it loose. To break the pipethread seal of the plug first tighten the plug just slightly (clockwise). This breaks the lock on the pipe thread, then turn the plug counterclockwise to remove it. You will find attached to the plug the remains of the annode (some oldtimers call it the calrod) all that will be left is the center wire that the magnesium was attached to. When the Magnesium Annode Rod is new it is about 5/8" in diameter and about 10" long.

Buy a new annode rod at your hardware store. Flush the heater tanks with fresh water into a pail and in about 3 days the smell will be gone. Yea!