Why does my apartment smell musty? A musty odor can be due to a lot of things. It can be a classic case of molds or lack of ventilation. You should also check for spills and messes as well as your HVAC system. Ultimately, a musty scent indicates that something in your home requires immediate cleaning.
It’s important to address the musty odor. If not, it will cause respiratory irritations and other health problems among the tenants. Also, the foul odor sets an ugly impression if you’re inviting guests over.
Below, I discuss the causes of musty odors in apartments and things you can do to remove them.
Why does my apartment smell musty?
Many describe the musty odor as an ‘old house’ scent. But if your apartment is new or clean-looking, something else is producing the odor. The following are some of the things you should check:
1. Molds and mildew

A musty smell is a hallmark sign that your apartment might be harboring molds and mildew. This is something you should act upon as molds can cause serious health problems.
Molds and mildew thrive in dark and moist places. It can be as simple as pipe leaks or stagnant water in the bathroom. If not cleaned, the mold spores will continue to proliferate and produce a strong, musty odor.
Take note that mold spores are naturally occurring everywhere. The air we breathe has small amounts of spores. But if your apartment becomes an ideal breeding place, the mold spores in the air will increase.
Also, it’s easy to have trapped moisture in an apartment due to its often enclosed designs. While there are still windows, it doesn’t offer enough ventilation at all times.
Even after the mold spores die, their odor and color will linger all over your home. The scent will attach to your carpet, curtains, and walls. By this time, it would be much harder to get rid of the smell.
2. Stagnant air
Lack of ventilation in your apartment can trap various odors and irritants, which can form a musty smell. In this case, it’s not necessarily molds but a combination of various pollutants.
Imagine hanging wet clothes inside your apartment with poor airflow. Pair that with cooking smells, shoe odor, body odor, and whatnot, and you’ll surely end up with a stinky place.
Airflow is vital to keep your apartment smelling fresh. While you can always use air fresheners, they will only mask the smell. Worse, the product may just worsen the odor and cause irritations to the occupants.
3. Dirty HVAC system

Another major culprit to lingering odors inside your apartment is a dirty HVAC system. Unfortunately, many tenants overlook this part, allowing bacteria and odor to form inside the vents. And after long periods of not using the system, turning it on once again will reveal the musty odor. Worse, all the ducts running through your apartment will spread a foul odor. It’s a large mess in the making.
Even if you’re only using your HVAC system from time to time, you shouldn’t underestimate the grimes that can accumulate inside the ducts. It can be a combination of dust, molds, moisture, and so on.
Even if you’re only using your HVAC system from time to time, you shouldn’t underestimate the grimes that can accumulate inside the ducts. It can be a combination of dust, molds, moisture, and so on.
4. Tobacco smoke
If you’re smoking inside your apartment, you shouldn’t be surprised if a musty smell will start to form. Indoor smoke leaves a lasting impression on walls, carpets, and furniture. In addition, the soot from tobacco smoke will adhere to surfaces, which will give it a yellowish tinge.
Aside from the discoloration, tobacco smoke also has a stubborn smell. The odor of nicotine can soak on fabrics like curtains, bedsheets, and rugs. If you’re not smoking, you should check whether the previous tenants do. Most of the time, tobacco smoke can linger even after general cleaning.
Take note that you should stop smoking indoors for two reasons: first, it will make your place stink, and second, it’s harmful to your family’s health.
Thirdhand smoke is real, and it occurs when a person gets in contact with residual nicotine from surfaces. It can be as simple as touching contaminated surfaces or breathing the off-gassing.
In short, the musty odor due to indoor smoking can still cause lung damage. In addition, children and infants are at a higher risk due to their tendency to mouth objects.
5. Uncleaned spills

Lastly, there might be uncleaned spills and mess all over your house. This is very common for apartment dwellers with young kids who are prone to tipping their food over.
The most common spots for spills are carpets and rugs. And since these materials absorb moisture well, the spill can go unnoticed. It will only become a problem once the substance starts forming a musty smell. By this time, it already clung to the carpet and will be a pain to remove.
Take note that spilled drinks and food can have a lingering smell that will last for years if you leave it sitting. Aside from food, pet accidents are also something to watch out for.
How to remove the musty odor in your apartment?
The musty smell in your apartment can be removed with the right approach. The following steps will help a lot:
✔️Find where the odor is coming from
The very first thing you should do is finding where the odor is coming from. Use your nose to trace where the musty odor is originating, so you’ll know what needs cleaning.
Inspect your apartment for signs of water leaks, mold, condensation buildup, and spills. This will tell you where you should start the next steps. It will also prevent you from missing the real cause of the problem.
If your nose isn’t successful in finding the source of the smell, you should hire professional water damage and mold removers. They have special tools that can check for water damage and leaks behind walls. They can also tell if the musty smell is indeed brought by molds.
✔️Vacuum your floors
Next, you should vacuum your floors to remove dirt that might be contributing to the musty smell. I suggest investing in a vacuum cleaner with a HEPA filter that will trap the mold spores. This will help reduce the musty odor if the cause is a mold and mildew problem.
Also, you should dust your house from top to bottom. This will let you examine all the parts of your home, which will help in finding the source of the pungent odor.
✔️Wash your fabrics
Once you’re done cleaning the floor, you should remove all the curtains, sheets, pillowcases, and drapes. Wash all of these to remove the lingering musty smell. However, you shouldn’t hang it back until you’ve figured out the main source of the smell.
You can use a solution of white vinegar and water as a pre-wash. However, you should be careful in doing so on colored fabrics as vinegar may affect colorfastness.
✔️Swing your windows open
While you’re washing the fabrics, it will help to open your apartment windows. This will allow the musty smell to dissipate and for fresh air to come in.
However, you should skip this step during the allergy season. While outdoor air will help for ventilation, it can also bring a slew of irritants that may worsen the indoor air quality of your home.
✔️Run an air purifier
An air purifier will be a big help in reducing the mold spores levels in your apartment. First, make sure that it has a CADR for pollen suitable for the floor area of your unit. This way, the purifier will clean the air efficiently without being overworked.
Also, consider getting an air purifier equipped with activated carbon or activated charcoal filters. These two filter types help neutralize malodors, including musty smells.
✔️Use a dehumidifier
You can also use a dehumidifier alongside an air purifier. The dehumidifier will suck out excess moisture in the air and surfaces of your apartment. This is a helpful device, especially if there are water leaks and molds in your unit.
But if your apartment has an extensive mold problem, I recommend hiring professional mold remediators instead. They have industrial-grade dehumidifiers that can eliminate spores faster, so mold won’t spread further.
✔️Clean your HVAC system
You should also hire a professional HVAC service to clean your ducts, filters, and other components. It’s best to let the pros do it, so mold spores won’t accidentally spread in case there’s a buildup on your ducts.
Take note that air conditioners and heaters need to be serviced regularly to prevent the formation of bad odors. For moderate use, twice a year would be fine. But if you’re using your HVAC system more frequently, you should hire professional cleaning every quarter.
You shouldn’t wait for your HVAC system to have a musty smell before you decide to clean it. Remember that it’s much easier and cheaper to maintain an air conditioning unit with routine checks.
✔️Hang activated charcoal bags
Activated charcoal bags are also helpful in absorbing the musty smell in your home. It may not be as powerful as air purifiers in removing odors, but it works well on areas like your bathroom, closet, and cabinets.
You can find activated charcoal bags in different sizes. The bigger it is, the longer it will last. It’s also available at a small price, so you can easily purchase a bunch for your entire apartment.
✔️Air out your upholstery
If possible, take your upholstery out to aerate it. For example, you can use the balcony of your apartment to aerate a few upholstery at a time. Direct sunlight will kill mold spores and neutralize the musty smell naturally. However, you should be careful as some upholstery materials can crack or fade when exposed to direct sunlight for long periods.
✔️Talk to your landlord
Lastly, don’t hesitate to raise the musty smell issue with your landlord. If the source of the musty smell is serious, you need to involve your landlord so he or she can handle the cleaning efforts. It’s usually included in the contract, which will help you save money and effort.
In some cases, the mold and mildew are so bad that your landlord will have to call professionals to have it cleaned. Take note that many states hold landlords accountable for livable and safe housing. This includes removing musty odors and molds present in the unit.
Frequently Asked Questions
Q: Is a musty smell dangerous?
A: A musty smell often indicates the presence of molds, which is dangerous to one’s health. If the odor makes you sneeze, cough, or have a runny nose, take it as a sign that your indoor air is polluted. You can hire indoor air professionals to identify if molds are responsible for the smell.
Q: Will a dehumidifier gets rid of a musty smell?
A: Dehumidifiers can help reduce musty smells, but it’s not the sole solution. This will work if the source of the odor is molds and mildew. However, if your HVAC system is the problem, you need proper cleaning and not just removal of moisture. Nevertheless, dehumidifiers will still work as supplemental equipment to fully get rid of the nasty scent.
Q: Why does my house smell musty all of a sudden?
A: A sudden musty odor might be coming from your air conditioner. It’s a sign that there’s mold and mildew forming inside, which means you need to hire a professional AC cleaning service. You should also get your ducts, drain line, and evaporator coils checked for dirt and damages.
Q: Why does my bathroom smell musty all of a sudden?
A: Musty odors are very common in bathrooms since the moisture and darkness allow molds to proliferate. Also, if your bathtub uses a liner, there’s a chance that moisture has accumulated underneath, and it’s already brewing molds. Poor ventilation and your choice of products may also trigger a musty odor.
Q: Why do basements smell musty?
A: Basements are notorious for molds, especially if it has been neglected for years. Moisture can easily seep through the walls since it’s recessed to the ground. Paired with undisturbed darkness, molds and other pests can thrive inside. Before you know it, a strong, musty, and pungent odor is overpowering your basement.
Final words
Why does my apartment smell musty? This odor can be due to molds, moisture, stagnant air, spills, and more. Whatever it is, you should find the root of the problem so that you can seek the necessary solutions. Most importantly, you should talk to your landlord if the musty smell is present even before you occupied the unit.
Did you ever encounter a musty smell in your apartment before? How did you deal with it? Share your tips below!

Home Air Quality is founded by Bernard K to provide information on Indoor Air Quality in Homes and enlighten people about what they need to know about creating and maintaining a comfortable and healthy home environment.
We believe that “Quality air brings a healthy life.”