Why Your Toilet Has A Sewage Smell and How to Remove It

Last Updated on July 28, 2023 by toilethaven

Why Does My Toilet Smell Like Urine/Sewage?

Two barriers prevent your toilet from emitting a foul sewage smell. The first is the toilet wax ring, and the second is the water at the bottom of the bowl.

A toilet wax ring is a round piece of molded wax sandwiched between the toilet’s bottom and the top of the closet flange. A properly sealing wax ring is both watertight and airtight.

If your toilet smells like sewage, it is highly likely that the wax ring is not sealing, allowing sewer gases and wastewater to leak through it. It could also be caused by a clogged vent stack, meaning sewer gases have nowhere to exit the drain line.

When your toilet smells like urine, the wax ring could fail to seal around the toilet allowing urine to leak through it. In some instances, it could be caused by male members of the family, especially young boys who miss the target while peeing. When the pee trapped under the seat dries, it smells unpleasant.

Replacing your toilet wax ring or unclogging a blocked vent stack/drainpipe will, most of the time, remove the bad smell from your toilet. Make sure also that the water level in the bowl is adjusted correctly.

In a properly functioning toilet drain, the sewer gases are supposed to escape through the vent stack, which runs out through the roof of the house. If the drainpipe or vent stack is clogged, the sewer gases will build up inside these pipes.

When you flush the toilet, the waste displaces the sewer gases, which are forced to break the water barrier at the bottom of the bowl and hence the bubbling/gurgling.

To prevent a backup, a clogged toilet drainpipe should be unclogged as soon as possible. That will be a more laborious and more expensive repair.

The following are some of the signs that you have a clog in your drainage, resulting in a toilet or bathroom that smells like a sewer:

1. Toilet Bubbles When Flushed

At the bottom of the toilet bowl, there is always a constant amount of water. This is possible because of the toilet’s U-shaped P trap.

This water prevents sewer gases from entering your bathroom and the entire house. Instead, the sewer gases move out through the vent stuck.

If the vent stuck has a blockade, the sewer gases will pile up inside the stuck, and when the pressure is more than the toilet P-trap water can contain, it starts escaping through the water, informing of bubbles, and you might hear a gurgling sound.

A clogged toilet drainpipe means waste cannot flow to the city sewer lines. As a result, toilet waste and sewer gases will pile up inside the drainpipe and eventually be forced out of the P-trap, which leads into your toilet and bathroom smelling of sewer gases.

2. Bathtub Drains Gurgles When The Toilet is Flushed

Sometimes it is clogged not only the toilet’s drain but also the main house drainpipe. The toilet and bathtub drain is connected to the main house drain.

If this is the case, waste will not flow out of your house but will pile up in the drain. Unlike a toilet bowl with bottled water to contain sewer gases, your bathtub drain doesn’t.

As a result, all the sewer gases in the drainage system will escape through the bathtub drain, often with a gurgling sound. The entire bathroom will therefore smell of sewer gases.

3. Toilet Gurgles when the Bathtub Drains

When your toilet bubbles when the bathtub drains, the house’s main drainpipe is clogged, and waste cannot flow out.

A bathtub holds a large amount of water, and when it drains, the water displaces the sewer gases trapped in the drainpipes, which are forced to escape through the toilet bowl. Because of the water at the bottom of the toilet, the toilet will be bubbling/gurgling as the sewer gases come up to the bathroom.

4. Toilet on a Septic Tank Smells Like Sewer Gas

If a toilet connected to a septic tank smells like sewer gas, it is either full or the drainpipe to the septic is clogged. Sewer gases are trapped in the system under pressure and, after some time, overcome the water barrier at the bottom of the toilet, manifesting as bubbling/gurgling when the toilet is flushed.

How Do I Get Rid of the Smell in My Toilet?

If your toilet smells like sewer gas or urine, you can get rid of the odor all by yourself, but if you run out of success, you can always call in a plumber.

The method will depend on whether the problem is a wax ring not sealing or a clogged drainpipe/vent stack. Let us starts with unclogging a drainpipe or vent stack.

1. Plunge the Toilet

A toilet plunger is a rubber cup with a stick handle used to unclog a toilet. It dislodges clogs by creating a pressure differential that forces the clog to be pushed further into the drain or sucked into the bowl.

Pick a good toilet plunger to form a good seal around the toilet drain opening. For the first plunge, do it slowly with a small opening at the plunger to remove all the air hence creating a vacuum.

After the first plunge, you can plunge more aggressively, and hopefully, the clog will be dislodged.

2. Snake the Toilet with an auger

A toilet auger is a long cable with a cranking handle and a head used to unclog toilets that cannot be unclogged with a plunger.

Unlike a plunger, the auger is inserted inside the toilet through the P-trap and into the drainpipe, acting on the clog directly. It will either shred the clog into pieces that flow down easily or pull them out.

Using a toilet auger can be difficult, especially for the first time. Read more on how to use it in this post.

3. Check and Unclog the Vent Stack

The vent stack is a vertical pipe that runs from the toilet drainpipe to the roof of your house to discharge sewer gases. If it is clogged up, the gases will have no way of going out and will be forced to escape through your toilet, bathtub drain, or any other house drain leaving behind a sewer smell.

To unclog the vent stack, climb to the top of your roof using a ladder armed with a garden hose. Try to see if you can use your hands to remove the clogs. It is usually a bird’s nest, dried leaves, dead rodents, or birds at the top of the vent.

If that’s impossible, pour water down the vent using the hose. The water will unclog the vent and wash down the clog.

Sometimes you will need to use a plumber’s snake to unclog a vent stack if the clog won’t just come out.

4. Call a Plumber

When all of the above fails, call in a professional plumber. A plumber is, without a doubt, more experience and has more sophisticated tools and equipment.

It will be expensive to use the services of a plumber, but a toilet is such an important facility to compromise on. A backup will happen if the problem is not fixed in good time.

A backup happens when the house’s drains are clogged, and the sewage starts to flow back through the toilet, bathtub drain, kitchen drain, or any other drain in the home.

5. Replace the Toilet Wax Ring

Materials Needed

  • New wax ring
  • New toilet bolts (optional)
  • Adjustable wrench
  • Putty knife
  • Newspapers
  • Rubber gloves
  • Old rag/towel
  • Mini-hacksaw (optional)
  • Sponge
  • Empty bucket

How to Replace a Wax Ring:

Step 1: Turn off the Water to the Toilet

Look for the shut-off valve located at the back side of the toilet on the left-hand side. Turn it clockwise. If you have a push/pull valve, pull it outwards.

Step 2: Drain the Toilet

  • Flush the toilet and hold the lever down to remove as much water as possible.
  • Remove the toilet lid and place it away in a safe place.
  • Use the sponge to soak the water at the bottom of the toilet tank and squeeze it out of the bucket.
  • Utilize the same sponge to dry out the water at the bottom of the toilet bowl. Make sure you have your gloves on.
  • Disconnect the water supply line from the toilet tank.

Step 3: Remove the Toilet

  • You will find two bolts on each side of the toilet, sometimes covered with plastic caps. Remove the caps and loosen the toilet bolts using the wrench.
  • Sometimes the bolts and nuts are corroded and won’t just come off. Use the mini-hacksaw to cut off the nut being careful not to cut the toilet body.
  • Hold the toilet by the bowl, rock it about to break the wax ring seal, then lift it off.
  • Place the toilet on its side on top of the newspapers.
  • Plug off the toilet drainpipe with the old rag/towel to keep sewer gases at bay.
  • Remove the old wax ring and trash it. Wax rings cannot be reused.
  • Using your putty knife, scrape off old wax from the top of the toilet flange and outlet.
  • Check the condition of the flange too. If it is broken, it will need to be replaced. Replacing a toilet flange is easy, especially with the toilet is already removed.

Step 4: Replace the Wax Ring

  • Slide the wax ring gently into the toilet outlet, careful not to deform it. An easier way to do it is to leave the wax ring outside in the sun for a while or dip it in warm water for a few minutes. This helps it slide in easily.
  • An alternative to using a wax ring is installing a rubber gasket seal. The rubber gasket is not as messy as a wax ring and works fine, if not better.
  • Slot in the toilet bolts and washers in the toilet flange.
  • Remove the rag/towel from the drainpipe.

Step 5: Install the Toilet

  • Lift the toilet and align the two holes on its base to the two bolts. Once aligned, lower it down gently. A toilet is heavy, and controlling its weight and aligning it with bolts is not easy. Have someone help you with this detail.
  • Push the toilet down gently to engage the wax ring fully.
  • Slot in washers and nuts in each bolt and tighten with the wrench alternatingly. You are advised to tighten the bolts alternatingly to keep the toilet level. Don’t, however, tighten too much to avoid cracking the bowl.
  • If the bolts protrude too much, cut them off with a hacksaw and cap them off.
  • Connect the water supply line to the toilet tank and turn on the water.
  • Place the toilet lid back on.

And that is how to fix a toilet that smells of urine and sewer gases. If you encounter challenges anywhere while fixing it, please feel free to call in a plumber.

Should You Caulk Around Your Toilet?

To caulk or not to caulk around your toilet is one area even plumbers disagree on. Those who oppose it say it is easier to notice when your toilet leaks.

Should you caulk around tour toilet, then? The best way to go about it is to caulk around the toilet and only leave a small opening at the back of the toilet. This way, you can notice any toilet leaks, and it is already hard to caulk the back of the toilet.

A caulked toilet is easier to clean and also prevents the toilet from rocking/wobbling. If a toilet is not caulked, spilled urine will flow and dry up below the toilet, leaving a foul smell. This is even worse when the toilet has been shimmed. Find more on this topic here.


A toilet that smells like sewer gases or urine can significantly compromise the joy of being at home. Home is where you go to relax after a long day at work. If it, however, turns out to be a place where sewer gas and urine smells reign strong, it stops being a home.


1. Why does my toilet smell even after cleaning it?

Two things: The toilet wax ring might not seal properly, which means sewer gases are coming out to your bathroom, or the toilet drain/vent stuck are clogged, making the sewer gases back up through your toilet or bathtub drain.

2. Why does my Toilet P-trap smell?

A toilet P-trap is the U-shaped part at the bottom of the toilet. It retains a small amount of water, preventing sewer gases from entering the bathroom. If the toilet drainpipe is clogged, sewer gases will force through the P-trap, and you might notice your toilet bubbling/gurgling.

The water can also dry up if the toilet has not been used for a while. Sewer gases will start moving up to your bathroom through the P-trap resulting in a foul smell.

3. Why does my toilet smell like rotten eggs?

A rotten egg smell in a toilet is an indicative sign of the presence of hydrogen sulfide. The hydrogen sulfide gas is a result of bacteria growing in drains. Therefore, a clogged toilet drainpipe is a perfect environment for the bacteria to multiply and hence the smell of rotten eggs.