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Water Smells Like Sulfur in One Faucet: 8 Possible Reasons Why!

water smells like sulfur in one faucet
Written by Jenny Molin

Fill a glass from the cold-water tap, take it outside and smell it. Repeat this test with hot water.

Do you feel your water smells like sulfur in both tests, or just one?

If you smell the odor in both samples, there’s a good chance the contamination is in the water supply.

If you smell it only in the hot water, the water heating is your prime suspect, and if you don’t detect the odor in either sample, it’s probably coming from the drain.

Whichever causes the odor, we have information below to help with the correct fix.

Let’s figure out why your water smells like sulfur in one faucet.

Water Smells Like Sulfur In One Faucet

water smells like sulfur in one faucet

1. Bacteria growing in the water heater

Your water heater may have bacteria growing in it which can produce a smell like sewage or rotten eggs.

The likelihood of this being the cause of your problem can be determined by how often it is used.

If a water heater is left idle for a period of time, if the thermostat is too low, or if the hot water often goes unused you are increasing the chances of bacteria growth.

2. Chemical reactions

Is it both the hot and cold water smelling of sulfur? If it is then the likely source is usually the water source itself.

Hydrogen sulfide gas is present in the underground water and released into your water supply.

If it is only the hot water that the odor is present in, then more than likely the culprit is your hot water tank being infested with sulfur bacteria.

This is a chemical reaction caused by the hot water and the magnesium rod present in it.

3. Bacteria growing in the drain

Bacteria growing in the drain

The most common cause of this smell is bacteria growing in the drain.

The accumulation of food waste and other organic matter on the drain walls will act as nutrients for the bacteria, allowing them to grow.

The bacteria then produce a gas with a rotten egg smell.

4. O-Rings are decomposing

Another cause is the o rings on your faucet may be decomposing.

Commonly known as Out-Gassing, this cause can be obvious sometimes as shrinkage can be observed but other times there can be no visible change.

The out-gassed molecules from the constituent ingredients can cause contamination in the water process and so replacing them should be one of your first checks.

5. Presence of hydrogen sulfide gas

Hydrogen sulfide gas is the cause of the smell. Whether it is coming from the water or the drain, it is not a pleasant taste or odor.

Produced by bacteria in sewage, contaminated pipes, and water or just in the ground, it is commonly known as sewer gas.

Discovering the root of the hydrogen sulfide gas will help you get rid of it.

6. Bacteria growing in the water source

If you have investigated the water heater and the drain and they are not the cause, then the issue could stem from the water source.

In the event of this, you need to be cautious moving forward and refrain from using the water until it has been fixed as it may be coming from harmful bacteria.

If your water comes from your own well then you can shock chlorinate the well and pump the water until the odor of chlorine has cleared.

On the other hand, if supplied by the city authority, you need to contact them or the department of health immediately.

7. Corroded pipes

Is the odor only affecting water from one faucet? If this is the case it is likely you have corroded pipes.

Over time corrosion will attack all pipes to some extent.

If bacteria get past the filters they can accumulate in all the cracks and crevices created by the corrosion.

You may need your pipes repaired in this area of your plumbing.

8. Bad rubber hoses

Is the smell coming from only one faucet? Rubber hoses connect faucets to pipes and these hoses have every likelihood of kinking or decomposing.

Whether it is a kink or decomposing causing cracks and gaps, there is a space for bacteria to get stuck and build up that may make the sulfur smell appear.

How To rid Your Water of Rotten Egg Smell?

How To rid Your Water of Rotten Egg Smell

Things you need

  • Chlorine bleach
  • Chlorinator
  • Iron removal filter
  • Aeration system
  • Peroxide
  • Air charger carbon filter
  • Ozone gas
  • PPE
  • Instructional material

Method 1: Concentrated chlorination treatment

A concentrated chlorination treatment, often called shock treatment, would be a good temporary solution.

Add a measured amount of chlorine to the water well and pump through the system until both the sulfur and chlorine smells have gone.

The smell of chlorine will be prominent in your home so run the water until it clears.

It is recommended to wait 24 hours before using this water and take note that the odors may reappear within a couple of months.

Method 2: Clear your hot water heater

If you have tested both your faucets and concluded the smell is only coming from the hot water then flushing your water heater would be your next action.

Leaving your water supply turned on, you need to connect a hose to the water heater drain valve and run it outside to a place you can collect the drained water as you will need to take a sample.

Fill a cup with the water after about ten minutes of draining and examine it for any sediment.

Keep draining the water heater until the water is clear of any small particles.

Method 3: Pour two quarts of cloroxchlorine bleach into the pipe

Does your water come from your own well? If so, this could be the fix for you.

First, store enough water in bottles to keep your household going for about two weeks.

Remember to consider all uses where it may be ingested such as cooking and brushing teeth as well as drinking.

Turn off the well breaker, remove the well cap, and pour two quarts of Clorox chlorine into the pipe.

After about 20 minutes pour four gallons of warm water into the pipe following the chlorine.

Replace the cap and the well breaker and let it run its course. It will take about two weeks for the cycle to complete and for the chlorinated water to clear.

Method 4: Add water filters

Another fix would be to install water filters in your house. This would be temporary though as they would need replacing every few months.

However, as well as being the cure, water filters could also be the source of the sulfur smell.

Check your sinks and faucets to try to isolate the odor and if it is an organic buildup of bacteria in your filter then remove and replace

Method 5: Disinfect your water heater

Measure forty gallons of water and then mix in four cups of hydrogen peroxide.

Pour the mixture into the tank until is full and run a small amount through the pipes and leave the remainder to sit for two hours minimum.

After that, clear the tank and replace it with new fresh water.

Method 6: Add a water softener

Chlorinated city water should eradicate any sulfur odors so if you have them then chances are you have your own well supplying your water.

You will need to clear out the iron that feeds bacteria to fully eliminate this problem from your source.

One way to do this is by installing a water softener system but be aware the systems themselves can become clogged which reduces their impact and could allow bacteria to accumulate.

Method 7: Increase the hot water heater temperature to about 160F

Another process to try would be increasing the temperature of your water heater.

You can do this very simply by increasing the temperature of your heater to 160 degrees and running it for a couple of hours.

Operating your water heater at this temperature should kill all bacteria.

Method 8: Modify your water heater

Step 1: Remove magnesium anode (Not recommended)

Removing the magnesium anode would be a logical way to eliminate odor caused by the magnesium and more than likely you would achieve the desired results.

However, this is actually quite a dangerous and costly idea as it will also remove the protection against rust.

This will then attack the weakest parts of your water heater and you will need to replace it after just a few years.

Step 2: Replace the magnesium anode with an aluminum anode

You can replace the magnesium anode with an aluminum one and not suffer the consequential chemical reaction causing lifespan-reducing rust.

Aluminum anodes are also cheaper than magnesium ones but they do come with their own drawback being that the anode will gradually dissolve leaving debris to harden and sink into the reservoir.

This can then get into your pipes and faucets causing internal damage which would create cracks for bacteria to grow in.

Step 3: Install a powered anode

If you intend on replacing the magnesium anode then the best option is to do so with a powered anode.

Made from titanium makes these anodes are insoluble and so they will not clog or damage your pipes.

They help remove the sulfur odor and last for several years.

Method 9: Call your city or county health inspector

If your water comes from the city supply then you need to contact your city or county, health inspector.

You do not know the cause of the sulfur odor and so you do not know whether it is harmless or not.

Make them aware of the urgency of the problem and the fact it is a health threat. They will need to react immediately.

What if you have no control over your water source?

As stated above you must contact your city or county health department immediately.

Public noticing odors resembling rotten eggs near drains need to be aware this is quite likely a sign of hydrogen sulfide in the water supply.

Even low levels of hydrogen sulfide can be detected and need eliminating.

This odor does not mean the water is harmful to your health or dangerous, but it may be.

Physical symptoms that can be caused by hydrogen sulfide are fatigue, headache, and nausea and psychological symptoms are anxiety and resentment.

If the hydrogen sulfide reaches air levels of a minimum of 2ppm for half an hour it can start to have a real impact on humans.

Sensitive groups such as asthmatics are most likely to feel the effects with minor irritations in their breathing.

You may also notice irritation in their eyes.

For these reasons, any detection of sulfur in the city water supply must be reported immediately.


Q. What does it mean when only one faucet runs smelly water?

If the odor is only emanating from one faucet, then it is much easier to isolate the source and fix the issue.

In this instance it will be a hot tap and your cause will be the water heater. Follow the steps above to resolve this problem.

Q. Will the sulfur smell go away on its own?

Run the faucet for about five minutes and the odor may disappear. If not then you will need to investigate further using the information above.

If it has, remember this may only be temporary so monitor this and if necessary, find the root of the problem and source the correct fix.

About the author

Jenny Molin

Interior Design Artist

Hello, I’m Jenny. I’ve been an interior design artist by profession since my B.S. in Interior Design. I’m a minimalist and prefer to save space when choosing fixtures, sinks and fittings. My style tends to make the most out of the least amount of space. The idea behind every interior design project is unique and it reflects personal style, taste and tradition. I’ve learned more when working than I ever did while I was studying in college. I worked in more than 12 hundred households all across the US and got positive feedback. I’ve been working with FaucetsReviewed as one of the founding members and regularly contributing to the site via testing and reviewing various interior fittings and fixtures.

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