Nobody wants to drink water that smells like rotten eggs. If you’re wondering why your water has a rotten egg smell and how you can fix it, you’ve come to the right place.
In this guide, we’ve shared the causes of a sulfur smell in water, and the best methods to get rid of the smell once and for all.
📌 Key Takeaways:
- A sulfur smell in well water is usually caused by the presence of hydrogen sulfide gas, which is naturally occurring in well water.
- If only your hot water smells like rotten eggs, the anode rod in your hot water heater might have sulfur bacteria or mineral buildup.
- You can fix a rotten egg smell in water by installing a water filtration system to remove hydrogen sulfide or flushing and servicing your water heater.
Table of Contents
👃 2 Common Causes of Rotten Egg Smell in Water
If your water has an eggy sulfur smell, it’s likely caused by one of the two issues:
Hydrogen Sulfide Gas In Well
If both your hot and cold water smells like sulfur, the most likely cause is hydrogen sulfide gas in your well.
Hydrogen sulfide gas usually emerges due to a combination of sulfate-reducing bacteria and sulfate (a naturally occurring element found in sedimentary rocks like limestone and gypsum rock).
When sulfate-reducing bacteria feed off sulfate, it reduces sulfate into sulfide, which creates hydrogen sulfide gas as a byproduct.
How much hydrogen sulfide in water is dangerous?
If we look at the Environmental Protection Agency (EPA) drinking water standards for this element, we can see that sulfate is classed as a secondary contaminant, meaning that it’s considered a nuisance in water but doesn’t pose a health risk. The secondary MCL (Maximum Contaminant Level) for sulfate is 250 ppm, while hydrogen sulfide has no MCL at all.
Even if you can smell a strong rotten egg smell in your water, hydrogen sulfide gas might not be present in dangerous amounts. A Texas A&M University study found that humans can detect the taste or smell of as little as 0.1 milligrams of sulfur in a water supply.
Hydrogen Sulfide In Electric Water Heater Tank
Your hot water heater might also be the cause of the sulfur in your water. If only your hot water has an eggy smell, the most likely cause is your heater.
A hot water heater has a magnesium anode rod that’s designed to prevent certain contaminants in your water from corroding the inside of the heater. Essentially, the anode corrodes first, minimizing the damage done to your heater. The idea is that the anode rod is replaced frequently to prevent your heater tank from ever corroding.
When an anode rod corrodes, free electrons are produced, which causes chemical reactions to occur between sulfate and sulfate-reducing bacteria. The result? Hydrogen sulfide is produced, with its distinctive rotten egg smell.
This sort of reaction most commonly happens if stagnant water sits in the heater for a long time. In most cases, it’ll disappear once you put the heater back into use, but some water heaters could produce hydrogen sulfide gas every night, and you might need to filter the sulfate-reducing bacteria out of your water.
Related: The Strange Reason Water Smells Like Sulfur In One Faucet
🧪 How To Detect The Cause Of Rotten Egg Odor In Water
You should have a hunch about the cause of your water’s rotten egg smell – but how can you be certain?
There are two steps we recommend:
Step 1: Compare your Hot and Cold Water
First, you need to work out whether the bad smell is due to hydrogen sulfide in your well water supply, or whether you just have sulfur bacteria in your hot water heater. Pour a glass of hot water and a separate glass of cold water.
Compare the smells (DON’T taste the hot water). If your water heater is to blame, your hot water will have a strong sulfur smell, while your cold water should smell fine.
Step 2: Test Your Water Supply
If both your hot and cold water have a sulfur odor, test your water to confirm the cause.
You can buy DIY tests for water hydrogen sulfide for around $25. Or, you could get your water tested by a laboratory for the most accurate results.
Most laboratories offer testing packages for well water, giving you a better understanding of your overall water quality and helping you to pinpoint the cause of your smelly water.
Once you know your test results, you can move on to the next step: deciding how to tackle the sulfur smell in your drinking water.
🚰 How To Treat Sulfur-Smelling Water: 4 Best Methods
Now you know the cause of your sulfur-smelling water, you probably want to get rid of it as soon as possible.
Here are the best ways to get rid of the rotten egg odor in your water supply:
Install A Water Treatment System
One of the best ways to treat water that smells of sulfur is to install a water treatment system.
Air Injection Oxidation
What do we recommend for sulfur removal? Our top pick would be an air injection oxidation system.
Air injection sends water through an air bubble, which oxidizes hydrogen sulfide gas, turning it into a soluble substance that can be filtered out of the system with a birm or manganese greensand media bed.
You can get similar results with an oxidizing media filter, which uses manganese dioxide to oxidize hydrogen sulfide before removing it in the same manner.
Install the filter at water’s point of entry into your home to ensure rotten egg sulfur smells are removed from your entire water supply.
Activated Carbon Filter
An air-charger carbon filter made from activated catalytic carbon is another effective way to remove hydrogen sulfide.
Activated carbon uses adsorption to grab onto contaminants contributing to poor taste and smell in water. It’s one of the most effective ways to improve water’s aesthetic properties.
However, this method only removes low levels of hydrogen sulfide (less than 0.3 mg/l) unless combined with other water treatments.
Chlorinate Your Water
Chemical treatment is another effective way to remove hydrogen sulfide and sulfur bacteria from your water.
You can use a chlorine injector system to add measured amounts of chlorine to your water. The system will store the water in a tank to allow the chlorine to take effect, then send the water into your home’s plumbing system.
Ideally, you should follow up with a backwashing catalytic carbon filter to further improve water’s smell and remove chlorine residues in your water before drinking.
Chlorine bleach is highly effective at removing large amounts of hydrogen sulfide (typically over 6 mg/L) from water, eliminating the rotten egg odor.
You can also use hydrogen peroxide (in a hydrogen peroxide injection system) in place of a chlorine bleach solution for the same effect. Hydrogen peroxide deoxidizes hydrogen sulfide gas, getting rid of unpleasant odors.
Increase Your Water Heater Temperature
A short-term solution to kill sulfur bacteria in your heater is to increase the water heater temperature to 160 degrees Fahrenheit.
Proceed with caution if you choose this method. Speak to your plumber if you’re unsure. And remember, the iron and sulfur bacteria will probably come back in the end, so this isn’t the best solution to eliminate odors continuously.
Replace Your Water Heater’s Magnesium Anode
If you’ve determined that sulfur bacteria on the anode in your water heater is causing poor-smelling water, the solution is to replace the anode.
Hire an experienced plumber to inspect your water heater and replace the anode for you. In most water heaters, the anode should last 3-5 years, but the exact lifespan depends on your water quality and the volume of water treated by the water heater per day.
❔ Water Smells Like Rotten Eggs: FAQ
Why does my water smell like rotten eggs?
Your water might smell like rotten eggs due to hydrogen sulfide gas in the water (especially likely if you have well water), or a buildup of sulfate minerals in your water heater’s anode. You can find out the exact cause of the rotten egg smell by testing your water.
Is rotten egg smelling water harmful?
No, rotten egg smelling water isn’t usually harmful – even if it does make water very unpleasant to drink. However, if you notice a particularly strong smell of sulfur in your water, you should test your water and take the appropriate action to be certain that your water isn’t harmful to your health.
Should I call a plumber if my water smells of rotten eggs?
No, you don’t usually need to call a plumber if your water smells like rotten eggs – but it’s situational. It’s unlikely that the rotten egg smell in your water will damage your plumbing in any way, but the hydrogen sulfide gas usually responsible for the smell may corrode your fixtures and pipes if left to do so. In this scenario, you might need to replace pipes if they’re badly corroded.
Can I shower if my water smells like rotten eggs?
Yes, you can shower if your water smells like rotten eggs. However, it probably won’t be a pleasant experience – nobody wants to smell rotten eggs when they’re trying to get clean – and you’ll probably want to address the issue.
Why does only my hot water smell of rotten eggs?
If only your hot water smells eggy, you probably have an issue in your heater. Hot water heaters can produce a rotten egg-like smell if sulfur bacteria grow on the heater anode. You can remedy this problem by getting a plumber to inspect your heater and replace the anode if necessary.