Why Does My Bathroom Sink Smell Like Sewer? 6 Common Causes And Solutions

Answering the question, “Why does my bathroom sink smell like sewer?” can be quite complicated. Fortunately, I’ve got the answers you’re looking for and their solutions.

The sewer smell in your bathroom sink is abnormal and can feel quite uncomfortable. The common causes of this unpleasant smell in your bathroom sink could be problems with your vent, P-Trap, blocked sewer line, or bacteria growth.

If you’re looking for the reasons and solutions to why your bathroom sink smells like a sewer, then you’ve recently perceived that stinking rotten egg smell from your bathroom sink. Ensure you read this piece to the end, as I answered other important questions in the FAQ section.

In this article, I will explain some of the reasons why your bathroom sink smells like sewer. I will also reveal how you can eliminate the sewage smell from your bathroom sink.

Common Causes of Sewer Smell in your Bathroom Sink and Their Solutions

You can save a few extra dollars when you understand what you need to fix. So, before you call your plumber, you should know about these six possible reasons and how to fix them.

Reason 1: Dry P-Trap 

A P-Trap is a U-shaped tube found under your bathroom sink. It is connected to the sink’s sewer drain. Its primary purpose is to stop sewer gas from entering your home.

The P-trap holds some water that acts as a barrier that blocks off sewer gas. However, when the P-trap water level is low, sewer gas smell may find its way into your home unhindered.

Solution: Fill in the P-Trap with water

If you have noticed that your P-Trap is dry, then a quick solution would be to fill it with water. The water will block the gas from flowing into your bathroom.

Reason 2: Blocked sewer line

If your sewer line is blocked, water won’t flow out of your home into the external drainage system. This means you would have a lot of stagnant water in your pipes.

This kind of wastewater produces a bad smell. Worse, it can obstruct sewer gas from flowing out of your pipes. This would force the smelling gas back into your home. Sometimes, the foul odor comes with an overflow in your sink.

Solution: Use a cup-shaped plunger to unclog the blockage

If you suspect something is blocking your sewer line, you can use a cup-shaped plunger to clear any minor blockages. If this doesn’t work out, you could have a blockage in your main sewer line.

In that case, use a plumber snake to unclog the blockage. You can rent one for as low as $20 a day.

Reason 3: Problems with your vent.

A blocked vent may be another reason your bathroom sink smells like sewer. Your vent pipe conducts sewer gas out of your house through the roof. The gas can return to your bathroom if your vent pipe is damaged or blocked.

Solution: Use a plumber snake to clear blockage

You can fix blocked vent pipes using a plumber snake or auger to remove blockages. If your pipe is damaged, you might have to call your plumber to replace it.

Reason 4: Damaged clean-out plug

The clean-out plug is that cylindrical cover on your sink’s pipe. Plumbers usually loosen this plug to work on your sink. Each pipe has clean-out plugs; you can often find them under your P-Trap.

Generally, these plugs seal the pipe and prevent sewer gas from spreading in your home. However, if this plug gets damaged, sewer gas can enter your home and make your bathroom stinks like sewer. The smell can even extend to your bathroom sink.

Solution: Replace your clean-out plug

The sewer smell from the bathroom sink can be really frustrating. To fix this, get a new clean-out plug and replace the old one. Install this new plug and test it to ensure the leakage is plugged.

Reason 5: A dry overflow channel

A dry overflow channel may be one of the reasons why your bathroom sink smells like sewer. The overflow channel stretches from the overflow hole in your sink and drains out excess water into your pipes.

The channel prevents water in the sink from spilling onto the floor. If your overflow channel is dried out, bacteria and debris can create a foul smell that escapes into your sink through the overflow hole, making your bathroom sink smell like a sewer.

Solution: Clean the overflow channel

You’d need to clean the overflow to fix the sewer smell in your bathroom sink. You can do this by washing it with the following items;

• A brush
• A  mixture of baking soda and vinegar
• Water. 

However, it’s essential to address the reason why the overflow dried up in the first place. It may be that the overflow does not work often or is not always in use. In that case, you’d need to keep it wet by occasionally flushing it.

Reason 6: Old or poor-quality pipes

Old pipes can have a lot of debris, which can cause your bathroom sink to stink like a sewer. Both old and poor-quality pipes have one thing in common — they are weak. And weak pipes can easily crack.

These kinds of cracks can cause sewer gas to leak into your home. Another problem with old pipes is that they can develop rough surfaces that accumulate debris and bacteria over time. This can also be the source of the foul odor coming from your bathroom sink. 

Solution: Patch or replace the old pipes

If you notice a leak in your bathroom pipes, your best bet is to patch or replace them. However, if your bathroom sink still smells like sewer after replacing the pipes, check the next section for other possible solutions. 

Other Possible Solutions to Fix The Sewer Smell In Your Bathroom Sink

After you have identified the causes of the sewage smell in your bathroom, fixing it should eliminate the sewer smell. However, depending on the problem, the odor may still linger.

You can clear this up by using any of the following methods.

Use air fresheners

Air fresheners and deodorizers can help you eliminate the sewer smell immediately. They often come in spray cans. You can quickly apply them around your bathroom sink by pressing the spray button.

Remember, this would work better if the source of the smell had already been taken care of.

Ventilate your home

When you ventilate your home, it can drive out a foul odor that comes from the bathroom sink. Open the windows, especially in your bathroom, to allow fresh air to circulate. Turn on the exhaust fan if you have any. It can also help with air circulation. 

Clean your bathroom sink with disinfectant.

Use disinfectant to clean your bathroom sink. This should eliminate any bacteria or debris responsible for the sewer smell.

A thorough cleaning can drive away foul odor in the bathroom very quickly, especially if the source of the stink has already been taken care of.

Thoroughly dry your bath mats and towels.

When your bath mats are not adequately dry, mold and mildew can grow underneath. Similarly, folding up your bath towels immediately after use or when they are not thoroughly dry welcomes mildew and mold growth.

Always make sure you thoroughly dry up these bathroom essentials after use. Also, you can use a dryer to dry your bathroom mat properly.

Conclusion

Congratulations, you made it to the last part, and I’m sure you’ll no longer be pondering, “Why does my bathroom sink smell like sewer?” Although there are several reasons why your bathroom sink smells like sewer.

But when you understand these reasons, it can help you eliminate the foul odor in your bathroom. It’ll also help you save some bucks. In most cases, fixing your plumbing system would drive the sewer smell in the bathroom sink away.

However, if you can’t wait for the smell to dissipate, you can ventilate your bathroom. Another possible solution is cleaning the bathroom sink with disinfectant or using air fresheners to remove the smell quickly.

Frequently Asked Questions

This section will cover some of your questions about the sewer smell in your bathroom sink.

Why does my bathroom smell like a sewer but no leak? 

If your bathroom sink smells like a sewer but your pipes aren’t leaking, then it could be any of the reasons below.

• A dry P-Trap
• A dry Overflow channel
• Problems with your vent

Why does my bathroom sink smell like rotten eggs when I run water? 

If sewer smell in your bathroom sink when running water, then any of these below could be the reasons;

• Contaminated water supply.
• Accumulation of bacteria in the drain.

Why does my bathroom smell when there is no blockage? 

Your bathroom sink can still smell like sewer even if there is no blockage in your sewer line. This could be due to the following reasons;

• Poor ventilation
• A dry P-Trap
• A dry overflow channel
• A damaged clean-out plug

What neutralizes the smell of sewage?

Baking soda and Vinegar are known to neutralize the smell of sewer in your bathroom. Air fresheners can help as well.

Can a clogged drain cause a sewer smell?

Yes, a clogged drain can cause a sewer smell. When a drain is clogged, it obstructs the flow of wastewater. As a result, the wastewater stagnates, allowing bacteria to accumulate, which can create that unpleasant sewer smell.