Why Your Bathroom Sink Smells Like Sulfur

Why Does My Bathroom Sink Smell Like Rotten Eggs (3 Easy Fixes)

The smell of rotten eggs in your bathroom is dangerous to your health.

The hydrogen sulfide gas (sewer gas) can cause headaches, nausea, dizziness, skin and eye irritation. Here’s why your bathroom sink smells like rotten eggs, and how to get rid of the problem fast.

When your bathroom sink smells like rotten eggs, the cause is likely contaminated water and drains, blocked vents, or a dry P-trap. Bacterial activity in a dirty sink drain produces the stinky hydrogen sulfide gas.

Cleaning and disinfecting the drain can stop the sulfur smell. You may also need to unblock your drainage vents.

The first thing you want to do is find out the exact source of the stinky smell. Is it the water, sink drain, or a single part of the system? 

Why Your Bathroom Sink Smells Like Sulfur

rotten eggs smell in bathroom

To get rid of a sulfur smell in your bathroom sink, you must first identify the cause.

The shower drain and the water itself are likely to be the source of the hydrogen sulfide gas.

The main source of the rotten egg smell in your bathroom is bacterial activity. Bacteria in the sewage, in the ground, or contaminated water pipes start to decompose matter and produce sewer gas as a by-product.

1. Contaminated water

There are times when you’ll notice a sewer smell when you turn on the hot water in your bathroom sink. In this case, the problem is in the hot water tank. 

  • A corroded magnesium sacrificial anode can produce a sulfur smell in hot water. To get rid of the smell, get a plumber to replace the corroded anode.
  • A sulfur bacterial growth may also occur in the hot water tank. While it is not harmful to you, it causes an unpleasant rotten egg odor in hot water. Chlorination of water usually kills sulfur bacteria and stops the sewer smell.

2. Contaminated overflow sink drain

contaminated sink pipe

You may have noticed a foul, sewer-like odor from the small overflow outlet hole in your bathroom sink. It is likely the odor is coming from the accumulation of bacteria at the end of the sink’s overflow hole.

Another possible reason for the rotten egg smell in your bathroom sink is outgassing.

Out-gassing is the release of unpleasant gases by plastic materials over time. Sinks made of a plastic material such as cultured marble are notorious with this problem especially when new.

The release of sewer gas due to outgassing is quite uncommon but you may want to check for that if your sink is new.

3. A dry P-trap

Every sink in your house has its drain connected to a P-trap. When you start to notice a sewer smell in the bathroom, the problem could be in this part (see image).

How-to-Stop-Rotten-Egg-smell-in-bathroom-sink

P-trap fixtures block sewer gas from escaping back up through your sink drains. When installed properly, this fixture should have some water in it. This water stops the hydrogen sulfide gas in the vents from escaping and contaminating your bathroom air.

  • P-traps dry out due to leakage, so check the fixture for any wetness on the outside.
  • If you haven’t used the sink for a very long time, the water in the P-trap may have evaporated.

If the sink hasn’t been used for a long time, you might want to check if there’s any water in there. Pour some hot water into the drain to remove any sediments that may have settled in the P-trap.

The buildup in the P-trap can force water to flow over them. You might also want to remove the fixture and clean it up to remove any sediments. If it is leaking, replace it to get rid of the rotten egg smell immediately.

4. Blocked vents

Slow drainage and gurgling sounds in your toilet are a sign of blocked vents in the drainage system. Whenever you flush your toilet or drain your bathtub, it creates air pressure that pushes up the sink drain.

How to Get Rid of Rotten Egg Smell in the Bathroom Sink

Male Plumber Fixing White Sink Pipe With Adjustable Wrench

Once you pinpoint the source of the rotten egg smell, you’ll be able to apply the right fix. Here are 3 ways to get rid of a stinky bathroom sink:

1. Spray Clorox into the overflow hole

Clorox bleach contains hypochlorous acid. This active ingredient has been found to kill bacteria.

  1. Put fresh Clorox bleach in a strong spray bottle.
  2. Spray plenty of that bleach into the overflow hole of your bathroom sink to kill bacteria.
  3. Allow a day or two and check if the rotten egg smell has stopped.

2. Clean the sink drain fixtures

It is possible that there’s a lot of gunk in the fixtures that make up your sink’s drain. Bacterial activity on this gunk can produce a stinky smell.

One way to get rid of the sulfur odor is to clean up the drain. You can do this yourself. Here’s how:

  1. Unscrew the nut on the pivot rod and remove it from the drain.
  2. Remove the pop-up stopper from your sink drain.
  3. Use a toothbrush and vinegar to clean the pop-up stopper and the pivot rod.
  4. Roll a paper towel or piece of cloth and push it down the drain using an appliance brush.
  5. Scrape the sides of that drain with the brush to remove all the biofilm in there.
  6. Remove the goose-neck from the wall by unscrewing it.
  7. Scrape out any sediments in the wall drain using a spoon.
  8. Clean the P-trap, gooseneck, pivot rod, and the pop-up stopper in a laundry tub full of water plus a cup of Clorox bleach.

Once you’re done cleaning, re-install everything properly. Pour plenty of hot water into the bathroom sink drain to remove any sediments in there. It will also disinfect the drainage system.

Here’s a great video that will help you with the steps above:

3. Unblock the vents

Start by plunging down the toilet may help clear anything that’s causing blockage. Start with the toilet in the same bathroom with the stinky sink.

If that doesn’t get rid of the sulfur gas from your sink, you’ll need to go to the roof to check the vent for any blockage. If it is something visible, remove it yourself. But if you can’t see what’s blocking the vents, call a plumber to help fix it.

Always Identify the Problem Before Fixing

Before you try any of these fixes, it is important to identify the source of the smell. Find out whether the rotten egg odor comes from.

One simple way of doing that is fetching a glass of water from that sink’s faucet. Go with it outside and smell it. If the water smells fresh, then the problem is in the sink drain and not the water.

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