The Strange Reason Water Smells Like Sulfur In One Faucet

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You’ve noticed a rotten egg smell in your water. But to make things complicated, the smell is only coming from one faucet in your home.

What’s the cause of the sulfur smell? Why is the smell only in one faucet? And how can you get rid of it?

We’ve shared everything you need to know in this guide.

📌 Key Takeaways:

  • If you’ve noticed a sulfur smell in one faucet, it’s most likely caused by bacteria growing in your hot water heater or corrosion in a water pipe.
  • Decomposing organic matter in the faucet drain might also be to blame for smelly tap water.
  • You can fix the sulfur smell in one faucet by determining the source of the smell and treating it accordingly.

👃 Water Smells Like Sulfur In One Faucet – What’s The Cause?

There are three most likely causes of the smell of sulfur in one faucet:

1) Bacteria Growing In Your Water Heater

The most common cause of rotten egg water smells is sulfur bacteria buildup in your water heater.

Water heaters have a magnesium heating rod called an anode rod, which prevents the heating tank from corroding. The idea is that the anode corrodes first, preventing damage from corrosive contaminants to the hot water tank itself.

When this rod corrodes, free electrons are formed. These cause chemical reactions between sulfate and sulfur-reducing bacteria, resulting in the production of hydrogen sulfide – and the distinct rotten egg smell.

You might wonder why only one faucet has the rotten egg odor, and not your entire hot water supply, if the source of the smell is your water heater.

The most likely reason is that the smell is strongest in the water faucet closest to the heater. The smell may be present in other hot water faucets, but it might not be strong enough for you to detect.

Stagnant water sitting for long periods in your heater is a common cause of bad smells in your water. In most hot water heaters, the smell will disappear once the heater is being used. For this reason, the water smell might be worse in the morning when you turn on the hot tap for the first time.

Corroded water heater anode

2) Corrosion or Clogging In A Water Pipe

A foul smell coming from your faucet could also be caused by corrosion in a water pipe supplying the faucet.

Certain minerals and organic materials in your water may gradually build up in your water supply line. As water flows through your plumbing system, these may be pulled back into your water from the pipes, resulting in water that smells like rotten eggs.

The smell might be present in only one faucet if one water pipe is corroding worse than others.

If corrosion isn’t to blame, a clog or a kink in the water pipe might be.

A kinked water pipe may trap sulfur, causing an eggy smell when you switch on your faucet.

3) Decomposing Organic Matter In A Drain

If you only notice the eggy smell when you turn on a specific tap at one sink, it’s possible that the smell isn’t caused by hydrogen sulfide gas in your water – but by decaying organic matter deposited in the sink drain.

When water flows through a drain that contains nasties like grease, fat, and food waste, the bacteria may produce hydrogen sulfide gas, causing the all-too-familiar rotten egg smell.

If you can smell the unpleasant odor when you either both hot or cold water faucets at your sink, the drain might be to blame – especially if the smell is coming from a kitchen sink that’s often used to wash dishes.

Food wastes in drain causing hydrogen sulfide smell

🔧 How To Fix Sulfur Smell In One Faucet

To fix sulfur in your water supply, follow these steps:

Step 1: Identify The Source

First, you need to identify the source of the smell.

If you can smell sulfur in both the hot and cold water at a certain sink, the cause of the smell is probably a blocked drain.

If only your hot tap water faucet has water that smells like sulfur, the source of the smell is most likely your water heater or a clogged or corroded pipe.

Hire a plumber to inspect your heater if you want to be certain of the cause before you attempt to treat the issue.

Step 2: Treat The Problem Accordingly

Depending on the cause, you could treat the problem in the following ways:

Replace Your Heater Anode

For problems with your water heater, the best way to fix smelly tap water from a certain faucet is to replace your heater’s anode. Hire a plumber to do this for you.

Your plumber might also recommend doing a hot water flush – changing the heater’s temperature to 160°F for 8 hours to kill anaerobic bacteria in the heating tank. Then, let the water cool and drain the tank. This method is only suitable for heaters that have a pressure relief valve.

Man installing new water heater anode

Flush Or Replace Pipes

If you think a pipe leading to your faucet is clogged or corroded, you can try flushing it by turning your faucet on fully and letting water flow through the pipe for 5 minutes. This should dislodge any accumulated sulfate and lift corroded particles.

In some cases, such as bad kinks or corrosion in old pipes, you might need to replace the pipes entirely.

Unclog Blocked Drains

For rotten egg odors caused by a clogged drain, the solution is to unclog the drain.

Mix equal parts baking soda, vinegar, and warm water, then pour the solution down the drain. This should get rid of the bacteria and eliminate the bad smell.

If you smell sulfur in your shower, make sure your shower drain isn’t blocked with hair.

Adding baking soda to boiling water and bathtub

📑 Final Word

Smelly water is unpleasant, and it can be frustrating to deal with the smell of rotten eggs in the water from just one faucet.

The sooner you can pinpoint the cause of the smell, the better. If you’re struggling to identify the smell, get a local plumber to visit your home. They’ve probably dealt with issues like yours on numerous occasions, and can quickly advise you on how best to eliminate the rotten egg odor from your water.

One final thing to note: if the smell is more like sewage than rotten eggs, you might have a much bigger issue that needs professional remediation.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

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