Sunrise Specialty » 6 Causes of Sewer Smell in the Bathroom (Tips to Fix)

6 Causes of Sewer Smell in the Bathroom (Tips to Fix)

Everybody likes having a clean, tidy, and pleasantly smell bathroom. Unfortunately, this is not always a case. Sometimes a sewer odor in the bathroom is so unpleasant that air fresheners or ventilation can’t help.

Sometimes, you can feel the stench after using the toilet. The same thing happens when you have a pile of unwashed laundry. However, the sewer smell in the bathroom means that you have a problem with drains you need to solve as soon as possible.

Dangerous Sewer Gases

Unfortunately, no matter how awful the bad odor from the pipes can be, the mere attack on your nose is not the worst effect of the sewer smell in the bathroom. For example, this place is full of gasses, such as methane, which are highly hazardous and can severely affect your health.

In most cases, methane causes headaches, dizziness, nausea, vomiting, and suffocation. If it accumulates, this gas is also highly flammable. That is the primary reason why discovering the source of sewer smell in the bathroom is crucial for your household.

Why does my bathroom smell like sewage

The toilet is the most common suspect for sewer smell in the bathroom. However, there are many other reasons for the bad odor. After a thorough check, you can discover a problem in the shower drain, clogged pipes, or wax ring around the toilet.

To find the source of the odor, you should use your nose as a significant ally. After thoroughly cleaning the bathroom, approach different corners and drains above the bathtub or floor, and try to determine where the smell is strongest.

Once you understand where the stink comes from, you can get rid of it. In most cases, it occurs from the sewer where accumulated organic waste, hair, and soap create a biofilm. In such a case, bacteria develop in it and cause a sewer smell in the bathroom.

1. The smell from a shower drain

The smell from a shower drain

Daily showering leads to the formation of sediment coming from dead skin cells, shower gels, and hair. Over time, these deposits clog the drain and cause both bad odors and slow water leak.

If your feet remain in the water after showering, it is time to clean the drain. Fortunately, this is something you can do yourself instead of calling a plumber. On the other hand, cleaning the sediments in the drain is an awful job, so call a professional to avoid doing this dirty task on your own.

Once you decide to clean the drain, the first thing you need to do is to remove the shower drain cover with a screwdriver. Then grab the prepared pot with a mixture of boiled water and white vinegar. Slowly pour water down the drain in a continuous stream.

Then, you need to pour one to two cups of baking soda and let it sit there for at least two hours. The third step is to pour boiling water into the stream one more time.

The combination of baking soda and vinegar will destroy deposits in the drain. Finally, use a drain brush to remove biofilm leftovers, let the water run for a few minutes, and screw the drain cover back into place.

Make a habit of combing your hair regularly before shower and clean the drain once a week with baking soda and vinegar to avoid future sewer smell in the bathroom.

2. Dry P-trap

One of the most common causes of odors in the bathroom is dry P-trap. The P-trap is a U-shaped pipe located under the sink. In typical cases, there is always a small amount of water in the P-trap, which prevents sewer gases from reaching the bathroom.

However, if some of your taps become dry because you don’t use them regularly, the P-trap will dry out over time. Therefore, the barrier preventing the spread of gasses is no longer there, and you will face sewer smell in the bathroom. Fortunately, this problem is straightforward to solve.

To return water to the dry P-trap again, open the tap and let the water flow to run for ten minutes. As a precaution, you can pour a little baking soda into the drain. However, if the sewer smell still persists, you should call a plumber because the source of the stink is not a dry P-trap. He will look for possible cracking and solve the problem.

3. Wax ring problem

Wax ring problem

The wax ring at the base of your toilet is essential because it creates a seal between the toilet bowl and the drain pipe. However, the wax ring can be damaged over time if the toilet bowl is not fixed correctly.

Therefore, the toilet can start leaking, and you will get stuck with water on the floor and an unpleasant sewer smell in the bathroom. The reason is passing the sewage gases through the wax ring so that you should replace it. Keep in mind that you need to empty the toilet before removing this part.

If the damage of the wax rung is severe, you may need to scrape it off the floor. Wear rubber gloves and use cleaning products to remove all existing traces. When you are done, set up a new wax ring and put the toilet bowl back in place.

4. Sink odors

Sometimes it happens that the sewer smell in the bathroom comes from the sink. The possible reason is clogging of the pipe that leads to dry P-trap. Like many others, your sink probably has a hole at the top that allows fast drainage when the sink is full of water.

However, if you don’t use the sink regularly, the grime and mildew will build-up there, which will cause an unpleasant odor. Solve this problem by scrubbing the inside of the sink with a brush. Then, pour hydrochloric acid or some commercial cleaning agent through the hole, leave it to act briefly, and rinse.

5. Water heater problem

Water heater problem

Although it is not a common source of sewer smell in the bathroom, the reason you feel an unpleasant odor may be the water heater.  If you don’t use it regularly or rarely turn it on at high temperatures, there is a high possibility that bacterial colonies form.

This unpleasant odor is specific and smells like rotten eggs, so you can quickly discover its origins. First, try to solve the problem by heating the water to the maximum, then flush it out to get rid of all the bacteria. Repeat this several times. If the smell is still there, it is time for a new water heater.

6. Water smell

What doesn’t usually come to your mind is that the problem can be in the water. In some regions, the water has a strange, sulfur odor. The reason is the content of hydrogen sulfide. Be careful if it is your case since this compound is highly dangerous and can jeopardize the health of you and your family.

Even if the stench comes and goes, it doesn’t mean that the problem is gone. On the contrary, it means that the level of this substance in the water varies, and you need to take a water sample to a lab for testing.

Although it can be present in small amounts, hydrogen sulfide can have consequences for you or your pets. The symptoms will range from loss of appetite, irritability, and headaches to the most severe, such as fainting, bronchitis, or pneumonia.

What makes this compound especially dangerous is that you become less sensitive to it over time. As a result, you can think that the smell is gone, although the hazardous substance is still in the water. Therefore, you need to solve this issue as soon as possible.

Call a Plumber

In most cases, you can remove the sewer smell from your bathroom on your own. However, if you hate doing this disgusting job or are not skillful enough, calling the professional is the right solution.

Sometimes, you may need help when it comes to a severe problem, such as a sewer backup when the water in the toilet and shower gurgles and comes back. In such a case, an unpleasant odor can be just an overture to the more severe issue.

A sewer backup can occur due to flooding but also pipe damage or tree roots that make a barrier in the yard. Sometimes the blockage of the main drain is also caused by the accumulation of debris. Whatever the cause is, the water will accumulate in the pipes and cause damage.

At first, the problem will occur in the bathroom and basement and then in the rest of your home. This situation is urgent, and it is necessary to call an emergency plumber to avoid more damage and higher costs.


What is certain is that you should never ignore sewer smell in the bathroom. In addition to being extremely uncomfortable, it can also impair your health.

You can quickly clean the clogged drain, remove the accumulated debris, and replace the wax ring around the toilet. Still, if the smell is persistent, it is time for the expert to take matters into their own hands.

8 thoughts on “6 Causes of Sewer Smell in the Bathroom (Tips to Fix)”

  1. we installed a new toilet, and the smell comes two or three times per week..have checked the fit, all good. have tried to flush it out, but to no avail.. what else could we do to eliminate the smell.. its so offensive.

    • I had some success cleaning the lines around the offending toilet. The nearby shower drain or bath tub drain may have accumulated the disgusting mucelage buildup. It worked for me, the toilet was sharing the drainage line with the shower. I snaked the shower and the smell retreated.

  2. Would there be a possibility that the smell could come from the exhaust vent in the bathroom ceiling?

  3. i have smell every once in awhile and decided it occurs when it was raining /low atmosphere pressure but goes away on bright clear days ….i assume i have a very small leak somewhere in connections to toilet or bidget.

    • I had a similar situation and ultimately found that tree roots had grown into the leach lines of my sewer. When it rained the ground water brought sewage stinch to the surface and it pooled on my driveway causing severe damage. The cure was to cut down to huge pine trees located at the junction box of my septic system. After they were cut we no longer had a sewage stench in our backyard/driveway.

  4. Sometimes but not always I leave a smelly dump in the toilet just to create that nasty odor to piss off my wife!

    • Love it Piss Flaps!!!! Ha hahahahaha !!!!!! I really enjoy a nice sense of humor. In the past, I’ve occasionally taken a great photo of an ugly pile of loose stools and text it to at least 10 people that I haven’t text from or heard from in at least a year. NOW THAT is an attention getter!


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