Why does my house smell musty out of nowhere?

Author: Prof. Viva Mills  |  Last update: Sunday, October 12, 2025

A musty smell in your home is a sign that something is not right. Mouldy and musty smells are similar in nature and both are caused by the presence of mould or mildew. Mould in your home can be damaging to your health and is caused by high humidity levels.

Why does my house all of a sudden smell musty?

Damp, mould and mildew are the most common causes of a musty or stale smell in houses, creating this smell by emitting gases known as microbial volatile organic compounds (MVOCs) as they grow.

Can a house smell musty without mold?

Humidity in the air is often the cause of mold, but it can also cause a strong smell even if no mold has formed. Dehumidifiers fix this issue, as does proper ventilation. However, in colder months especially, it may not be feasible to vent the entire house.

What might a musty smell indicate the presence of?

The top causes of musty odors in bathrooms are from fungal growth. Mold and mildew are types of fungus found in damp spaces, like bathrooms. The constant presence of moisture in bathrooms creates an environment where fungus can thrive.

How to find the source of musty smell?

Check crawlspace and attic for sources of moisture intrusion. Musty smell is often caused by mold and mildew coming from those areas. I'd also recommend painting the entire house with Kilz primer, and then your paint of choice over that, just to block out any of the original owners smell.

How to Get Rid of Persistent 'Old House Smell'

What if I smell mold but can't find it?

When a homeowner smells mold but visual clues are invisible to the naked eye, then mold testing can be performed by a professional to locate the colonies. A mold testing kit can also be inexpensively purchased from the local hardware store and utilized by the homeowner.

Why do I smell a musty smell everywhere I go?

Phantosmia is a condition that causes you to detect smells that aren't actually in your environment. It can happen in one nostril or both — and the odors may be foul or pleasant. Common causes include colds, allergies, nasal polyps and dental issues. Treatment depends on the underlying cause.

Why have I started smelling musty?

Serious liver disease can make breath smell musty or like garlic and rotten eggs. Compounds that are transported through the blood can also be released through your sweat glands. That can make your armpits and skin smell bad. It's normal for stress to cause smelly compounds to be released through your sweat.

How do I find out where a bad smell is coming from in my house?

If odors seem to be emanating from this part of your home, check the following locations:
  1. Trash Cans. Under counter trash cans are a frequent source of odors. ...
  2. Ovens. Baked-on foods in your oven can cause burning or smoking odors when your oven is in use. ...
  3. Cooktops and Hoods. ...
  4. Disposals. ...
  5. Dishwashers. ...
  6. Refrigerators. ...
  7. Cabinets.

What does toxic mold smell like?

Black mold has an infamous, recognizable odor. Detecting this scent could be crucial in identifying a mold problem before it causes too much damage. Experts describe black mold as smelling musty—comparing it to rotting wood or leaves or wet, sweaty socks.

Why does my house smell weird all of a sudden?

Common Causes of Bad Odors in a Home

Some common culprits include: Bacteria:Some strains of bacteria give off foul-smelling compounds when breaking down organic matter like food waste. Fungus: Molds and mildew emit volatile organic compounds and are often the cause when a house smells musty.

Does a musty smell automatically mean mold?

General dampness, repeated condensation, and high humidity can sometimes bring on a musty smell. Since dampness can also facilitate mold growth it's likely that mold is beginning to form once you start noticing a musty smell.

What are signs of mold sickness?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

Can musty smell be something other than mold?

Summary. You might be dealing with plumbing leaks, water damage in hidden spots, or washing machine drain issues if your house smells musty but no mold is visibly present. The first thing to do is identify the source of the smell before attempting to eliminate the unwanted odor.

How do you get rid of a musty smell in your house fast?

How to Get Rid of Musty Smells
  1. Get a Dehumidifier. ...
  2. Install an Air Purifier. ...
  3. Give Your Home a Deep Cleaning. ...
  4. Remove Musty Odor in Fabric With Baking Soda. ...
  5. Practice Good Laundry Habits. ...
  6. Keep Your Return Air Filter Clean. ...
  7. Attack Whole-House Odors With Natural Odor Fighters. ...
  8. Don't Forget Your Pets.

Why do old people's houses smell musty?

“Old people smell” in the house often comes from the buildup of nonenal, a chemical that skin naturally produces more of as people age. This substance, combined with inadequate ventilation, insufficient cleaning, and the presence of fabrics that can trap odors, contributes to the distinctive smell.

How do I find the source of a musty smell in my house?

Identify the Source of the Musty Smell

If the smell isn't tied to any clothing or linens, you'll want to inspect common areas of the house that are susceptible to mold and mildew growth such as bathrooms, attics, and basements.

What does radon smell like?

Radon gas has no colour, smell or taste and is completely imperceptible to humans, even in high concentrations. Radon occurs naturally in the rocks and soil beneath us, but there is no way of knowing how much is escaping from the ground and entering a building.

Why do I smell mold when there is none?

An olfactory hallucination, known as phantosmia, makes you detect smells that aren't in your environment. The odors you notice in phantosmia are different from person to person and may be foul or pleasant. You may notice the smells in one or both nostrils.

Why does musty smell come and go?

The smells can have several different causes, but the most common is the growth of mildew or mould on walls or in cupboards. Improving the ventilation in your home to circulate the air more can help to reduce the impact of the smell, but in order to stop the smell for good, you will need to address the cause: mould..

Is it bad to breathe in musty smell?

A moldy odor suggests that mold is growing in the building and should be investigated. The health effects of inhaling mVOCs are largely unknown, although exposure to mVOCs has been linked to symptoms such as headaches, nasal irritation, dizziness, fatigue, and nausea.

Why do I suddenly have odor?

Body odor is caused by a mix of bacteria and sweat on your skin. Your body odor can change due to hormones, the food you eat, infection, medications or underlying conditions like diabetes. Prescription-strength antiperspirants or medications may help.

What type of brain tumor causes phantom smells?

a brain tumour in the temporal lobe could lead to sensations of strange smells (as well as other symptoms, such as, difficulty with hearing, speaking and memory loss)

Why do I smell musty after sleeping?

As we sleep, our bodies naturally shed skin cells, secrete natural oils and may lightly sweat – although some people may sweat more than normal. [5] If you're sweating a lot at night, it could also mean bacteria is building up overnight, leaving an unpleasant smell to wake up to in the morning.

Why do I smell musty despite good hygiene?

Body odor (BO) is caused by bacteria and sweat, but it can also be influenced by factors such as hormones, certain medications, infections or other medical conditions, and the foods you eat. You can have strong body odor even if you practice good hygiene.

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