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Why Does My Water Heater Smell Like Rotten Eggs?

Why Does My Water Heater Smell Like Rotten Eggs?

“Eww, what’s that smell?”

Are you smelling a strong “rotten eggs” or sewer gas smell coming from your water heater, especially when you run hot water?

That “rotten egg” smell is caused by hydrogen sulfide (H2S), which is a colorless, flammable and highly hazardous gas.

Hydrogen sulfide doesn’t dissolve in water, so when you turn on the hot water tap, the heat makes the hydrogen sulfide escape into the air, hence the unpleasant odor.

Small amounts of hydrogen sulfide in your water don’t cause any problems, but according to University of Georgia Extension (UGA), when H2S exceeds 1.0 ppm (parts per million) in your water, it can ruin your pipework and affect the taste of your drinks and cooked food—so it’s something you want to get rid of ASAP.

In this article, we’ll discuss 2 major points:

  1. How hydrogen sulfide entered your water in the first place
  2. What you can do to eliminate H2S

Let’s start with how hydrogen sulfide got into your water…

How hydrogen sulfide entered your water in the first place

There are 2 main ways how hydrogen sulfide can enter your water…

Cause #1: Sulphur-reducing bacteria

Here’s the condensed version (so we don’t turn this into a science class): Sulphur-reducing bacteria (SRB) use sulfur as an energy source, and are common in oxygen-deficient environments such as deep wells, plumbing systems and water heaters.

You can think of SRB as magicians who turn sulfates into hydrogen sulfide. More scientifically, when SRB come into contact with sulfates, they reduce them to hydrogen sulfide—hence their name.

If your home has a high count of this kind of bacteria then that could be what’s causing that foul, smelly odor.

Cause #2: A corroded magnesium anode rod in water heater

Your water heater comes with an anode rod, which is supposed to protect your water heater tank from rust. The rod essentially draws rust to it in place of your tank.

Many water heaters have an anode rod made out of magnesium. Magnesium anode rods supply electrons that aid in the conversion of sulfate to hydrogen sulfide gas—just like the sulphur-reducing bacteria can.

WARNING: If you’re using an ion exchange water softener, it’s making the problem worse. That’s because softened water increases the rate at which the magnesium rod corrodes, creating more hydrogen sulfide.

3 ways to get rid of hydrogen sulfide in your water

Below are 3 ways to reduce hydrogen sulfide in your water to get rid of that bad smell…

Solution #1: Shock chlorination

Shock chlorination is used to disinfect tanks, wells and/or water distribution systems. This cleansing process kills the cluster of sulphur-reducing bacteria (those magic bacteria that create H2S), thereby eliminating the bad smell.

Learn more about shock chlorination procedures.

Solution #2: Proper water filtration

The type of filter you need depends on the level of hydrogen sulfide. For more information about different types filters, contact a plumber. They’ll be able to provide filter recommendations.

Solution #3: Replace the water heater anode rod

If your rod looks corroded and nasty (like the image in Cause #2), it’s time to replace it. If you had a magnesium rod, you’ll want to find one made of aluminum or zinc.

Watch is DIY video on how to replace a dirty anode rod, or contact a plumbing professional for help.

Need some help from a professional Florida plumber?

Contact Aztec Plumbing to schedule a water heater repair today. We’ll send one of our trustworthy technicians to your home to get rid of that stinky smell once and for all.

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Categories: plumbing tips.