Why Does My Apartment Smell Like Sewage?

The last thing you would want when you come home after a long day at work is an apartment that smells of sewage.

While you may be tempted to shut the door and run away, deep down you know you have to face the music.

Or in this case, face the odor and follow your nose to the source.

Obviously, it’s a plumbing problem, and like most problems with plumbing, it involves a leak (in one form or the other).

But in this case, it’s an invisible leak. Sewer gas has found a way to seep into your apartment.

But don’t jump to the conclusion that it’s coming from your toilet.

Toilets tend to get all the blame while in most cases, something else is causing it.

The challenge is finding precisely where.

  • A clogged drain?
  • A dry P-trap?
  • A cracked or rotted drainpipe?
  • Or perhaps a loose pipe connection.

But back to the poor often maligned toilet. Yes, it might be the source, yes, while it could be your toilet, but it’s not what you think.

Sewer gas could be coming through the loose wax ring between the base and the flange.

Some of these problems have do-it-yourself fixes and others require a call to the management or the building super.

What is Sewer Gas?

When human wastes break down they release a conglomeration of gases.

The main ones are methane, ammonia, and hydrogen sulfide. All of these are unpleasant but put them together, and they can produce an overwhelming smell.

But then you already know that since it greeted you the moment you opened the door.

Other than posing an aesthetic problem, sewer gas can be a health problem.

Methane and the bacteria in it can cause headaches, nausea, and vertigo. What’s more, it’s combustible. It can explode and cause a fire.

For more about the harmful effects of sewer gas, check out Healthline — an online source of health and wellness information

Now that you understand sewer gas, it’s time to get on with the search.

What can Cause Sewage Like Smell in Your Apartment?

There are some usual suspects that you can look into when you smell sewer gas.

Clogged Drains

Organic matter can also cause a build-up of sewer gas. This includes hair that might be clogging your bathroom or shower drain.

Another culprit is the soap or body wash you use when you shower or take a bath, as well as shampoo, hair conditioners, and shaving cream.

And although the thought may gross you out, another cause is the mix of toothpaste, saliva, and plaque you spit out when you brush your teeth.

Leave any of these in place long enough, and they will result in biofilm.


Biofilm is the slimy substance that you may find from time to time coating the ring around your bathroom or shower drain or when clearing a hairball from the shower drain.

But biofilm is more than just slime. It’s a collection of various types of bacteria along with their organic wastes.

Although it’s not likely you will catch anything from biofilm, it does happen occasionally; especially when it is left to collect in a kitchen drain or around the faucet.

As in many things, when it comes to keeping your drains clean, an ounce of prevention goes a long way.

Using a sink screen in all your sinks to catch hair and debris is the first step, but don’t forget to clear it daily, then go a step further.

Take a disinfecting wipe to it, or give it a thorough whoosh of a disinfectant spray.

Those are daily practices. At least weekly soak the screen in bleach.

And if you notice mildew and stains forming around the drain, wipe them up immediately before they have a chance to set. But what should you do if a clog does form?

The Fix?

A toothbrush will come in handy for reaching clogs near the top of the drain. But for those deeper down, you can use a wire.

Bend it into a small hook at the top and sink it down as far as it can go. Pull it up and clean off the debris clinging to it.

You can also use some drain wires that you can easily order online (example shown below)

Vastar 3 Pack 25 Inch Drain Snake Hair Drain Clog Remover Cleaning Tool

Rinse and repeat as many times as it takes.

If the sink is still slow to drain it’s time to call the building manager or janitor.

And if you find this inconvenient or need any encouragement in picking up the phone, consider this alternative.

Clogged drains have been known to belch up putrid water and bacteria that have been marinating deep in their drainpipes!

Dry P-Traps

P-traps are the segments of U-shaped pipe found underneath the sink or tub. Their purpose is to trap and hold some of the drain water.

This standing water serves as a seal to prevent sewer gas and odor from creeping up and into your apartment.

However, a p-trap works only if the sink or tub is regularly used.

Otherwise, it runs dry and the sewer gas has a free entrance.

If you regularly shower at the gym, or if your job requires you to be away from home for extended periods of time, your tub’s p-trap will dry out.

The Fix?

If you know you’re going to be away or prefer not to use a certain sink or shower, you can take a preventative step.

Regularly run water down its drain for a few minutes. This will replenish the P-trap.

Then pour a couple of tablespoons of oil down the drain.

This will form a layer to prevent the water from evaporating.

If the odor remains, or you notice drops of water under the P-trap, it has a weak spot in it. Or it could be the drain pipe itself.

In either case, it’s time to call in some professional help. Call the apartment management.

Overflow Buildup

The overflow mechanism in bathroom sinks often gets overlooked. Look to see if your sink has one built into it.

This is a hole or slit near the upper edge of the sink.

It’s right where you stand when you shave, wash your face or brush your teeth.

As its name promises, its purpose is to prevent water from spilling to the floor should you accidentally overfill the sink.

If you detect a sewage odor when you are performing any of these, it could be there’s a buildup in the overflow.

Take a look and if you see mildew or grayish spongy grime, this is the case.

The Fix?

Cleaning the overflow is a relatively simple job you can do yourself. In fact, you should include it in your regular maintenance chores.

All it takes is a small bottle brush and a solution made of half bleach and half water.

Use the brush to scrub the inside of the overreach to remove the grime and mildew. Now use it to spread the water and bleach as far as the brush will reach.

Then pour the remainder of the solution into it. It should freely flow down into the sink’s interior.

Yes, it may be a messy job, but it’s better than waiting for the super to do it!

Loose Pipes

If pipes are not connected properly, when they are installed, sewer gas can leak in through even the most minute of gaps.

This can happen either because you have old pipes or new ones that were not connected properly.

The Fix?

You can’t fix this yourself. Since most pipes are out of sight behind walls or ceilings a plumber needs to be called in.

Bubble Bubble Toilet Trouble

We saved the toilet until last to make up for all the times it’s been falsely accused of being the smelly culprit.

However, the truth is sewage gas can indeed emanate from the toilet from three places – one of which is inside the bowl.

  • The first thing to look for is a wax ring gone bad
  • The second is one of the two seals that attach the toilet bowl to the drain
  • The third is a crack in the bowl’s porcelain

Damaged Wax Ring

The toilet flange, also known as a closet flange, is a round piece of metal with a few holes in it.

Its purpose is to reinforce the toilet’s connection to the sewer drain.

A wax ring reinforces this airtight connection, ensuring that human waste can flow swiftly down the drain without leaking.

Wax rings can last anywhere between 20 and 30 years but if the toilet itself becomes loose and wobbly, it can damage the wax ring.

When this happens, sewage can leak out and with it the signature smell of sewage.

Another weak spot can occur if either of the seals attaching the toilet to the drain dries out or is compromised in some other way.

The Fix?

If you notice water pooling in crevices around the bowl, it’s a dead giveaway that it’s one of the seals. In this case, it just needs re-caulking.

Scrape off the old caulk and apply a new layer. But be proactive. Do the same to the other, even if it looks okay,

If you can rock the toilet bowl, then the problem is the wax ring. It needs to be replaced.

These are both simple jobs you may be able to do yourself. But since you are paying good money in rent, you might as well let the landlord take care of it.

Cracked Toilet Bowl

Your toilet bowl could be cracked, broken, or damaged in some other way.

This often happens if someone has been too aggressive when snaking out a blockage.

It may also be that there are cracks around the bolts that fasten the bowl to the floor.

Even minuscule cracks can provide a passageway for sewer gas.

The Fix?

A professional plumber may be able to repair the cracks. But why not ask for a new toilet bowl?

What the Sewer Smell is from the Water?

All of the above problems are maintenance issues that can be easily taken care of.

But if you think the smell is coming from the water itself, it’s a serious matter of concern.

If it’s noticeable only when you turn on the hot water, bacteria may have gotten into the water heater.

The Fix?

No matter whether your apartment has its own water heater or there’s a boiler in the basement supplying the whole building, this is definitely a matter that warrants a call to your landlord or the management agency.

But if both faucets issue smelly water, do not hesitate to call the management.

Since this is most likely occurring in every apartment in the building, you may not be the first to apprise him of the situation.

The ball is now in his court. He needs to have the water tested in a lab to find out what is in it.

Then he needs to take the steps required to supply the building with clean odorless water.

Look on the Bright Side

If you own your own home, the problems described above would be your headaches.

You’d either have to pay someone to remedy them or spend your weekends attending to them. But if you rent it costs you nothing.

All you have to do is call the landlord

Think of this the next time you write a rent check. It should sweeten the chore.

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