Hot Water Smell Like Rotten Eggs (Why & What Can Be Done)

There might be nothing worse than when the hot water in your home smells horribly of rotten eggs. But if this is happening to you, don’t worry! 

Not only are you not alone, but we also have all the information you need to figure out right now why the hot water in your house smells like rotten eggs and, even more importantly, how to fix it and get that smell to go away! 

If your hot water smells like rotten eggs, it’s because there is hydrogen sulfide gas in your water. The excess gas can come from sulfur-reducing bacteria (SRB) in your water supply or corrosion of anode rods in the hot water heater. You can fix the problem by flushing the hot water tank, trying a chlorine shock treatment, or installing new anode rods. 

What is this rotten egg smell?

The first thing you need to understand if your hot water smells like rotten eggs is what is actually causing the odor. 

Although it smells like rotten eggs, it’s actually the smell of hydrogen sulfide gas. 

You may be interested to know that it is a common misconception that the chemical sulfur has a foul odor. In fact, sulfur is odorless, it is the compound that creates hydrogen sulfide gas that creates the egg-like smell. 

However, the smell of hydrogen sulfide gas is not even the worst thing about it! It is also flammable, corrosive, and even poisonous in large amounts. 

But before we find out how to get rid of this gas and the rotten egg smell, you first need to know what’s causing it. 

Two common causes of the hydrogen sulfide gas

Now, it’s time to talk about the two common causes of the hydrogen sulfide gas that causes the rotten egg smell in your water: Sulfur-reducing bacteria and the corrosion of anode rods in hot water heaters. 

Sulfur-reducing bacteria

Most water has some sulfur-reducing bacteria in it. And while water from a municipal plant will hopefully be clean, some can slip through. 

It’s also important to note that well water often has a far higher sulfur-reducing bacteria count as the water is not filtered as effectively before being pumped into your home. 

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Now, sulfur-reducing bacteria itself has no known health risks. However, when these bacteria feed off sulfates, hydrogen sulfide gas is formed, which can be quite dangerous and smells awful. 

So if your water supply has a high SRB count, the gas created throughout your plumbing and water systems could be causing the rotten egg smell. 

Corrosion of anode rods in hot water heater

Another common cause of the rotten egg smell in your hot water is that the anode rods in the water heater are corroding. 

Anode rods are found in hot water heaters and are used to collect minerals that would typically corrode the tank. 

Although anode rods are necessary to keep your tank and your water clean, if they start to corrode themselves, then they can cause the rotten egg smell in your water. 

Usually, anode rods are made from aluminum or magnesium, and when they corrode, the minerals in the rods react to the sulfur in your water which then creates hydrogen sulfide gas within your tank. 

And, of course, this gas is exactly what causes water to smell like rotten eggs. 

How to remove the sulfur smell

Next, you’re probably wondering how to get rid of the sulfur smell in your hot water! And luckily, we have four solutions right here that will do the trick. 

Flush the hot water tank

The first tactic to get rid of the rotten egg smell is to remove the hydrogen sulfide gas from your hot water tank. 

As you now know, this gas is created when sulfur-reducing bacteria feeds on the sulfur in the minerals in your water. So in order to get rid of it, you can simply flush your hot water tank. 

Here’s what you need to do:

  • Turn off your hot water tank’s thermostat.
  • Turn off the gas to the water heater.
  • Turn off the cold water supply
  • Then, turn on the hot water in your sink or bathtub and leave it on for the remainder of the project. 
  • Connect a garden hose to the drainage spigot on the tank.
  • Send the end of the hose outside or place it in a bucket or drain. 
  • Turn on the cold water spigot on your hot water heater.
  • Allow the water to drain until it runs clear. 

Then simply reverse these instructions to start your clean hot water tank back up again! 

Many homeowners don’t know that you should actually be flushing your hot water tank every 6 months for the cleanest possible water. 

Try a chlorine shock treatment

The next option to try is a chlorine shock treatment. And while there are quite a few steps to follow for this tactic, all you need is bleach to make it happen!

chlorine shock treatment
  • Turn off the electrical and gas supply to the water heater. 
  • Turn off the water supply to the tank. 
  • Using the drain valve and a garden hose, drain several gallons of water into a bucket, outside, or down a drain.
  • Remove the anode rod at the top of the tank
  • Pour in one gallon of household bleach for every 30 gallons of water in your tank. 
  • Close the opening where you put the bleach in.
  • Turn the water valve back on and allow the tank to fill. 
  • Turn on hot water faucets around your home until you notice a chlorine smell, then turn them back off. 
  • Leave the bleach in the tank for between 1-3 hours. 
  • Then drain the bleach water out through the garden hose. 
  • Refill the tank with fresh water. 
  • Replace the anode rod.
  • Allow all the taps in your home to run until there is no more chlorine smell.
  • Turn the electrical and gas supply back on. 

Hopefully, your hot water no longer smells like rotten eggs! But if it does, there are still two more solutions to try. 

Install new anode rods

The problem causing the rotten egg smell may be that the anode rods in your hot water tank are simply too corroded and need to be replaced. 

While there are various types of anode rods, including aluminum and magnesium models, if you want to protect your water from hydrogen sulfide gas, you should opt for a zinc or aluminum-zinc alloy anode rod.

Although you can purchase a new anode rod and replace the old one yourself, it can be a little tricky. 

However, if you want to give it a go, here’s what you need to do:

  • Turn off the electrical and gas supply to the hot water heater.
  • Shut off the water supply. 
  • Open a hot water faucet in your home to relieve the pressure inside the tank. 
  • Loosen the anode rod using a wrench. 
  • Be extremely careful, as corroded anode rods can disintegrate. 
  • Install the newly purchased zinc anode rod. 
  • Turn the water, gas, and electrical supply back on. 

It’s important to note that if you want to replace the anode rod yourself, you may want to opt for a more flexible option, so it’s easier to install. 

Add a water filtration system by a professional

The last tactic on our list will certainly get rid of the rotten egg smell in your hot water, but it will cost you quite a bit more than any of the other options. 

You can opt to add a water filtration system to your plumbing system; however, you will absolutely need a professional installation expert to do so. 

However, a filtration system does so much more than just remove hydrogen sulfide gas. It will also improve the quality and taste of your drinking water, reduce mineral buildup, make your clothes and body cleaner, and save you money in the long run on future plumbing problems! 

Is it time for a plumber?

Finally, now that you know what causes the smell of rotten eggs in your hot water and even what you can do yourself to try to fix the problem, it’s important to understand when it is time to call a professional plumber. 

Repairs/ replace rods/ cost

Realistically, if you don’t feel comfortable replacing the anode rods in your hot water tank or various other repairs it might need, then you will have to call a plumber to do so. 

While an anode rod will only cost about $50, to have it professionally installed is usually between $250-$300. 

And although it’s almost impossible to say how much it will cost for repairs to your hot water heater as there could be a variety of issues, you should expect to pay at least $200-$700 if you need professional help. 

Add new filtration system costs

As well, if you realized the cause of your rotten egg smell is excessive sulfur-reducing bacteria, you should consider paying a professional to install a filtration system for your water. 

A new filtration system can cost anywhere between $500 and $10,000, depending on the type, size, and brand you opt for. 

So it’s vital that you do your research first or ask a professional which filtration system will work best for your home and your water supply.

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