Why does my water smell like rotten eggs?

Like most of Florida, we have hard water here in the City of San Antonio. As such, it’s often the case that there are trace amounts of sulfur-bacteria in our water. While you won’t smell it or taste it when the water is cold or lukewarm, you’ll often smell it when the hot water is on.

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Here’s why: Water rusts metal. That’s as true for rain water left on your bike outside as it is for water inside your hot water tank. The reason your iron-lined water heater doesn’t corrode despite being full of hot water is because each and every tank-filled water heater comes with an anode rod. These rods take on the bulk of the corrosion that would otherwise ‘attack’ your tank, so that your tank lasts longer.

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What causes the smell:  While many people assume it's the sulfur-bacteria itself that creates the smell of rotten eggs, it’s actually the bacteria reacting to the aluminum and/or magnesium in the anode rod of your water heater.

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The Right Way to Fix It
The tried-and-true way to remove the “rotten eggs smell” from your hot water tank is to replace your water heater’s anode rod with a zinc-aluminum anode rod. While the aluminum will fight against corrosion, the zinc will combat the reaction that creates the rotten egg smell.

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*Please keep in mind: Removing a water heater anode rod is very difficult, since they tend to be installed securely inside water heater tanks, often below several components that will need to be removed first—using special plumbing tools—before you can access it.

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A quick word about water softeners
If you have a water softener installed, a zinc-aluminum rod may not fix the problem entirely. Water softeners can contribute even more to the smelly water problem, and often require an even more powerful solution to fix. In those instances we recommend you consult a licensed plumber.